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  • 1.
    Alavioon, Ghazal
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Garcia, Andrea Cabrera
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    LeChatelier, Magali
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Maklakov, Alex A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich, Norfolk, England.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich, Norfolk, England.
    Selection for longer lived sperm within ejaculate reduces reproductive ageing in offspring2019Ingår i: EVOLUTION LETTERS, ISSN 2056-3744, Vol. 3, nr 2, s. 198-206Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Males produce numerous sperm in a single ejaculate that greatly outnumber their potential egg targets. Recent studies found that phenotypic and genotypic variation among sperm in a single ejaculate of a male affects the fitness and performance of the resulting offspring. Specifically, within-ejaculate sperm selection for sperm longevity increased the performance of the resulting offspring in several key life-history traits in early life. Because increased early-life reproductive performance often correlates with rapid ageing, it is possible that within-ejaculate sperm selection increases early-life fitness at the cost of accelerated senescence. Alternatively, within-ejaculate sperm selection could improve offspring quality throughout the life cycle, including reduced age-specific deterioration. We tested the two alternative hypotheses in an experimental setup using zebrafish Danio rerio. We found that within-ejaculate sperm selection for sperm longevity reduced age-specific deterioration of fecundity and offspring survival but had no effect on fertilization success in males. Remarkably, we found an opposing effect of within-ejaculate sperm selection on female fecundity, where selection for sperm longevity resulted in increased early-life performance followed by a slow decline, while females sired by unselected sperm started low but increased their fecundity with age. Intriguingly, within-ejaculate sperm selection also reduced the age-specific decline in fertilization success in females, suggesting that selection for sperm longevity improves at least some aspects of female reproductive ageing. These results demonstrate that within-ejaculate variation in sperm phenotype contributes to individual variation in animal life histories in the two sexes and may have important implications for assisted fertilization programs in livestock and humans.

  • 2.
    Alavioon, Ghazal
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Hotzy, Cosima
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Nakhro, Khriezhanuo
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Rudolf, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Scofield, Douglas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Zajitschek, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Spanish Natl Res Council, Donana Biol Stn, Seville 41092, Spain.
    Maklakov, Alex A
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Univ East Anglia, Sch Biol Sci, Norwich NR4 7TJ, Norfolk, England.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Univ East Anglia, Sch Biol Sci, Norwich NR4 7TJ, Norfolk, England.
    Haploid selection within a single ejaculate increases offspring fitness2017Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, nr 30, s. 8053-8058Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An inescapable consequence of sex in eukaryotes is the evolution of a biphasic life cycle with alternating diploid and haploid phases. The occurrence of selection during the haploid phase can have far-reaching consequences for fundamental evolutionary processes including the rate of adaptation, the extent of inbreeding depression, and the load of deleterious mutations, as well as for applied research into fertilization technology. Although haploid selection is well established in plants, current dogma assumes that in animals, intact fertile sperm within a single ejaculate are equivalent at siring viable offspring. Using the zebrafish Danio rerio, we show that selection on phenotypic variation among intact fertile sperm within an ejaculate affects offspring fitness. Longer-lived sperm sired embryos with increased survival and a reduced number of apoptotic cells, and adult male offspring exhibited higher fitness. The effect on embryo viability was carried over into the second generation without further selection and was equally strong in both sexes. Sperm pools selected by motile phenotypes differed genetically at numerous sites throughout the genome. Our findings clearly link within-ejaculate variation in sperm phenotype to offspring fitness and sperm genotype in a vertebrate and have major implications for adaptive evolution.

  • 3. Hough, Josh
    et al.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Barrett, Spencer C. H.
    Otto, Sarah P.
    Evolutionarily Stable Sex Ratios And Mutation Load2013Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 67, nr 7, s. 1915-1925Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Frequency-dependent selection should drive dioecious populations toward a 1:1 sex ratio, but biased sex ratios are widespread, especially among plants with sex chromosomes. Here, we develop population genetic models to investigate the relationships between evolutionarily stable sex ratios, haploid selection, and deleterious mutation load. We confirm that when haploid selection acts only on the relative fitness of X- and Y-bearing pollen and the sex ratio is controlled by the maternal genotype, seed sex ratios evolve toward 1:1. When we also consider haploid selection acting on deleterious mutations, however, we find that biased sex ratios can be stably maintained, reflecting a balance between the advantages of purging deleterious mutations via haploid selection, and the disadvantages of haploid selection on the sex ratio. Our results provide a plausible evolutionary explanation for biased sex ratios in dioecious plants, given the extensive gene expression that occurs across plant genomes at the haploid stage.

  • 4.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Arnqvist, Göran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Perin Otto, Sarah
    Ploidally antagonistic selection maintains stable genetic polymorphism2012Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 66, nr 1, s. 55-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Understanding the maintenance of genetic variation in the face of selection remains a key issue in evolutionary biology. One potential mechanism for the maintenance of genetic variation is opposing selection during the diploid and haploid stages of biphasic life cycles universal among eukaryotic sexual organisms. If haploid and diploid gene expression both occur, selection can act in each phase, potentially in opposing directions. In addition, sex-specific selection during haploid phases is likely simply because male and female gametophytes/gametes tend to have contrasting life histories. We explored the potential for the maintenance of a stable polymorphism under ploidally antagonistic as well as sex-specific selection. Furthermore, we examined the role of the chromosomal location of alleles (autosomal or sex-linked). Our analyses show that the most permissible conditions for the maintenance of polymorphism occur under negative ploidy-by-sex interactions, where stronger selection for an allele in female than male diploids is coupled with weaker selection against the allele in female than male haploids. Such ploidy-by-sex interactions also promote allele frequency differences between the sexes. With constant fitness, ploidally antagonistic selection can maintain stable polymorphisms for autosomal and X-linked genes but not for Y-linked genes. We discuss the implications of our results and outline a number of biological settings where the scenarios modeled may apply.

  • 5.
    Immler, Simone
    et al.
    Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England..
    Gonzalez-Voyer, Alejandro
    CSIC, EBD, Dept Integrat Biol, Seville 41092, Spain..
    Birkhead, Tim R.
    Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England..
    Distinct evolutionary patterns of morphometric sperm traits in passerine birds2012Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 279, nr 1745, s. 4174-4182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The striking diversity of sperm shape across the animal kingdom is still poorly understood. Postcopulatory sexual selection is an important factor driving the evolution of sperm size and shape. Interestingly, morphometric sperm traits, such as the length of the head, midpiece and flagellum, exhibit a strong positive phenotypic correlation across species. Here we used recently developed comparative methods to investigate how such phenotypic correlations between morphometric sperm traits may evolve. We compare allometric relationships and evolutionary trajectories of three morphometric sperm traits (length of head, midpiece and flagellum) in passerine birds. We show that these traits exhibit strong phenotypic correlations but that allometry varies across families. In addition, the evolutionary trajectories of the midpiece and flagellum are similar while the trajectory for head length differs. We discuss our findings in the light of three scenarios accounting for correlated trait evolution: (i) genetic correlation; (ii) concerted response to selection acting simultaneously on different traits; and (iii) phenotypic correlation between traits driven by mechanistic constraints owing to selection on sperm performance. Our results suggest that concerted response to selection is the most likely explanation for the phenotypic correlation between morphometric sperm traits.

  • 6.
    Immler, Simone
    et al.
    Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England.
    Griffth, S. C.
    acquarie Univ, Dept Biol Sci, Sydney, NSW 2109, Australia.
    Zann, R.
    La Trobe Univ, Dept Zool, Melbourne, Vic 3086, Australia.
    Birkhead, T. R.
    Univ Sheffield, Dept Anim & Plant Sci, Sheffield S10 2TN, S Yorkshire, England.
    Intra-specific variance in sperm morphometry: A comparison between wild and domesticated Zebra Finches Taeniopygia guttata2012Ingår i: Ibis, ISSN 0019-1019, E-ISSN 1474-919X, Vol. 154, nr 3, s. 480-487Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Zebra Finch Taeniopygia guttata is a model bird species for the experimental study of behavioural and evolutionary concepts in captivity and especially sexual selection. The validity of sexual selection studies of domesticated birds is of long-standing concern as little is known about the influence of domestication on sexually selected traits. Most domesticated Zebra Finch populations are maintained under a strict breeding regime to avoid potential inbreeding. However these breeding regimes may interfere with the processes of sexual selection and influence the evolution of sexually selected traits because they may limit or prohibit active mate choice. Here we investigated the potential impact of a monogamous breeding scheme in a domesticated population in which active mate choice is largely inhibited, on the evolution of sperm morphometry as a sexually selected trait. We compared sperm morphometric traits (total sperm length and length of sperm head, midpiece and flagellum), and the variance thereof, between a domesticated and two wild Zebra Finch populations. Although we found significant differences between the three populations for certain sperm traits (head length, midpiece length), which may be of importance in postcopulatory sexual selection, overall, variance in sperm morphometry did not differ between the domesticated and the wild Zebra Finch populations. Our results validate the use of domesticated Zebra Finches for further studies of postcopulatory sexual selection and sperm competition.

  • 7.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Hamilton, M. B.
    Poslusny, N. J.
    Birkhead, T. R.
    Epifanio, J. M.
    Post-mating reproductive barriers in two unidirectionally hybridizing sunfish (Centrarchidae: Lepomis): Lepomis)2011Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 24, nr 1, s. 111-120Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The evolutionary sequence of events in the evolution of reproductive barriers between species is at the core of speciation biology. Where premating barriers fail, post-mating barriers, such as conspecific sperm precedence (CSP), gamete incompatibility (GI) and hybrid inviability (HI) may evolve to prevent the production of (often) costly hybrid offspring with reduced fitness. We tested the role of post-mating mechanisms for the reproductive isolation between two sunfish species [bluegill (BG) Lepomis macrochirus and pumpkinseed (PS) Lepomis gibbosus] and their first-generation hybrids. Performing in vitro sperm competition experiments, we observed asymmetric CSP as main post-mating isolation mechanism when BG and PS sperm were competing for PS eggs, whereas when sperm from both species were competing for BG eggs it was HI. Furthermore, hybrid sperm - although fertile in the absence of competition - were outcompeted by sperm of either parental species. This result may at least partly explain previous observations that natural hybridization in the study system is unidirectional.

  • 8.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Hotzy, Cosima
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Alavioon, Ghazal
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Petersson, Erik
    Arnqvist, Goran
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Sperm variation within a single ejaculate affects offspring development in Atlantic salmon2014Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 10, nr 2, s. 20131040-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is generally believed that variation in sperm phenotype within a single ejaculate has no consequences for offspring performance, because sperm phenotypes are thought not to reflect sperm genotypes. We show that variation in individual sperm function within an ejaculate affects the performance of the resulting offspring in the Atlantic salmon Salmo salar. We experimentally manipulated the time between sperm activation and fertilization in order to select for sperm cohorts differing in longevity within single ejaculates of wild caught male salmon. We found that within-ejaculate variation in sperm longevity significantly affected offspring development and hence time until hatching. Whether these effects have a genetic or epigenetic basis needs to be further evaluated. However, our results provide experimental evidence for transgenerational effects of individual sperm function.

  • 9.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Otto, Sarah Perin
    Univ British Columbia, Dept Zool, Vancouver, BC V6T 1Z4, Canada.
    Driven Apart: The Evolution of Ploidy Differences between the Sexes under Antagonistic Selection2014Ingår i: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 183, nr 1, s. 96-107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sexual reproduction in eukaryotes implies a biphasic life cycle with alternating haploid and diploid phases. The nature of the biphasic life cycle varies markedly across taxa, and often either the diploid or the haploid phase is predominant. Why some taxa spend a major part of their life cycle as diploids and others as haploids remains a conundrum. Furthermore, ploidy levels may not only vary across life cycle phases but may also differ between males and females. The existence of two life cycle phases and two sexes bears a high potential for antagonistic selection, which in turn may influence the evolution of ploidy levels. We explored the evolution of ploidy levels when selection depends on both ploidy and sex. Our analyses show that antagonistic selection may drive the ploidy levels between males and females apart. In a subsequent step, we explicitly explored the evolution of arrhenotoky (i.e., haploid males and diploid females) in the context of antagonistic selection. Our model shows that selection on arrhenotoky depends on male fitness but evolves regardless of the fitness consequences to females. Overall we provide a plausible explanation for the evolution of sex differences in ploidy levels, a principle that can be extended to any system with asymmetric inheritance.

  • 10.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Otto, Sarah Perin
    The evolution of sex chromosomes in organisms with separate haploid sexes2015Ingår i: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, nr 3, s. 694-708Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The evolution of dimorphic sex chromosomes is driven largely by the evolution of reduced recombination and the subsequent accumulation of deleterious mutations. Although these processes are increasingly well understood in diploid organisms, the evolution of dimorphic sex chromosomes in haploid organisms (U/V) has been virtually unstudied theoretically. We analyze a model to investigate the evolution of linkage between fitness loci and the sex-determining region in U/V species. In a second step, we test how prone nonrecombining regions are to degeneration due to accumulation of deleterious mutations. Our modeling predicts that the decay of recombination on the sex chromosomes and the addition of strata via fusions will be just as much a part of the evolution of haploid sex chromosomes as in diploid sex chromosome systems. Reduced recombination is broadly favored, as long as there is some fitness difference between haploid males and females. The degeneration of the sex-determining region due to the accumulation of deleterious mutations is expected to be slower in haploid organisms because of the absence of masking. Nevertheless, balancing selection often drives greater differentiation between the U/V sex chromosomes than in X/Y and Z/W systems. We summarize empirical evidence for haploid sex chromosome evolution and discuss our predictions in light of these findings.

  • 11.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Pitnick, Scott
    Parker, Geoff A.
    Durrant, Kate L.
    Luepold, Stefan
    Calhim, Sara
    Birkhead, Tim R.
    Resolving variation in the reproductive tradeoff between sperm size and number2011Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 108, nr 13, s. 5325-5330Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spermatozoa are amongst the most variable cells, and three factors are thought to account for this variation in design: fertilization mode, phylogeny, and postcopulatory sexual selection. In addition, it has long been assumed that a tradeoff exists between sperm size and number, and although postcopulatory sexual selection affects both traits, empirical evidence for a tradeoff has so far been elusive. Our recent theoretical model predicts that the nature of a direct tradeoff between sperm size and number varies with sperm competition mechanism and sperm competition risk. We test these predictions using a comparative approach in two very different taxa with different sperm competition mechanisms: passerine birds (mechanism: simple raffle) and Drosophila fruit flies (sperm displacement). We show that in both groups, males increase their total ejaculate investment with increasing sperm competition risk, but whereas passerine birds allocate disproportionately to sperm number, drosophilids allocate disproportionately to sperm size. This striking difference between the two groups can be at least partly explained by sperm competition mechanisms depending on sperm size relative to the size of the female reproductive tract: in large animals (passerines), sperm numbers are advantageous in sperm competition owing to dilution inside the female tract, whereas in small animals (drosophilids), large spermare advantageous for physical competition (sperm displacement). Our study provides two important results. First, we provide convincing evidence for the existence of a sperm size-number tradeoff. Second, we show that by considering both sperm competition mechanism and dilution, can we account for variation in sperm size between different taxa.

  • 12.
    Immler, Simone
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och evolution, Zooekologi.
    Taborsky, Michael
    Sequential polyandry affords post-mating sexual selection in the mouths of cichlid females2009Ingår i: Behavioral Ecology and Sociobiology, ISSN 0340-5443, E-ISSN 1432-0762, Vol. 63, nr 8, s. 1219-1230Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Females mating with multiple males may obtain direct benefits such as nuptial gifts or paternal care or indirect (i.e. genetic) benefits resulting in higher-quality offspring. While direct benefits are easily identified, it is difficult to determine indirect benefits, and it is hence largely unclear how they are obtained. This is particularly true in species with external fertilisation, where females seem to have little control over fertilisation. In cichlids, most maternal mouthbrooders show sequential multiple mating, where females visit several males for egg deposition. Genetic data revealed that multiple paternity of eggs and young in the mouth of females is common, but behavioural data of female spawning decisions are missing. Here, we test four hypotheses to explain female multiple mating in the maternally mouthbrooding cichlid, Ophthalmotilapia ventralis: (1) fertilisation insurance, (2) genetic bet-hedging, (3) female choice and (4) 'sperm shopping' (i.e. induction of sperm competition resulting in sexually selected sperm). Detailed observations of spawning behaviour in the field combined with histological analyses of the male reproductive organs suggest that fertilisation insurance, genetic bet-hedging and pre-mating female choice are unlikely to explain the sequential female multiple mating in O. ventralis. Instead, cryptic female choice by sperm shopping, i.e. post-mating sexual selection, is most compatible with our data and might be the major ultimate cause of multiple mating in females of this species and of mouthbrooding cichlids with maternal care in general. Our study provides new insight into ultimate causes of sequential polyandry in species with external fertilisation, as hitherto post-mating sexual selection by cryptic female choice has been assumed to be incompatible with external fertilisation mechanisms except by components of the ovarian fluid.

  • 13.
    Kotrschal, Alexander
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Corral-Lopez, A.
    Zajitschek, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kolm, Niclas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Positive genetic correlation between brain size and sexual traits in male guppies artificially selected for brain size2015Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 28, nr 4, s. 841-850Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Brain size is an energetically costly trait to develop and maintain. Investments into other costly aspects of an organism's biology may therefore place important constraints on brain size evolution. Sexual traits are often costly and could therefore be traded off against neural investment. However, brain size may itself be under sexual selection through mate choice on cognitive ability. Here, we use guppy (Poecilia reticulata) lines selected for large and small brain size relative to body size to investigate the relationship between brain size, a large suite of male primary and secondary sexual traits, and body condition index. We found no evidence for trade-offs between brain size and sexual traits. Instead, larger-brained males had higher expression of several primary and precopulatory sexual traits - they had longer genitalia, were more colourful and developed longer tails than smaller-brained males. Larger-brained males were also in better body condition when housed in single-sex groups. There was no difference in post-copulatory sexual traits between males from the large- and small-brained lines. Our data do not support the hypothesis that investment into sexual traits is an important limiting factor to brain size evolution, but instead suggest that brain size and several sexual traits are positively genetically correlated.

  • 14.
    Kotrschal, Alexander
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Rogell, Björn
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Bundsen, Andreas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Svensson, Beatrice
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Zajitschek, Susanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Brännström, Ioana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Maklakov, Alexei A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kolm, Niclas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    The benefit of evolving a larger brain: big-brained guppies perform better in a cognitive task2013Ingår i: Animal Behaviour, ISSN 0003-3472, E-ISSN 1095-8282, Vol. 86, nr 4, s. E4-E6Artikel i tidskrift (Refereegranskat)
  • 15.
    Maklakov, Alex A
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England..
    Carlsson, Hanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Denbaum, Philip
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Lind, Martin I.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Mautz, Brian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Hinas, Andrea
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England..
    Antagonistically pleiotropic allele increases lifespan and late-life reproduction at the cost of early-life reproduction and individual fitness2017Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 284, nr 1856, artikel-id 20170376Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Evolutionary theory of ageing maintains that increased allocation to early-life reproduction results in reduced somatic maintenance, which is predicted to compromise longevity and late-life reproduction. This prediction has been challenged by the discovery of long-lived mutants with no loss of fecundity. The first such long-lived mutant was found in the nematode worm Caenorhabditis elegans. Specifically, partial loss-of-function mutation in the age-1 gene, involved in the nutrient-sensing insulin/insulin-like growth factor signalling pathway, confers longevity, as well as increased resistance to pathogens and to temperature stress without appreciable fitness detriment. Here, we show that the long-lived age-1(hx546) mutant has reduced fecundity and offspring production in early-life, but increased fecundity, hatching success, and offspring production in late-life compared with wild-type worms under standard conditions. However, reduced early-life performance of long-lived mutant animals was not fully compensated by improved performance in late-life and resulted in reduced individual fitness. These results suggest that the age-1(hx546) allele has opposing effects on early-life versus late-life fitness in accordance with antagonistic pleiotropy (AP) and disposable soma theories of ageing. These findings support the theoretical conjecture that experimental studies based on standing genetic variation underestimate the importance of AP in the evolution of ageing.

  • 16.
    Maklakov, Alexei A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    The Expensive Germline and the Evolution of Ageing2016Ingår i: Current Biology, ISSN 0960-9822, E-ISSN 1879-0445, Vol. 26, nr 13, s. R577-R586Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The trade-off between survival and reproduction is the bedrock of the evolutionary theory of ageing. The reproductive system regulates ageing of the soma, and removal of germ cells extends somatic lifespan and increases resistance to a broad variety of abiotic and biotic stresses. The general explanation for this somatic response is that reduced reproduction frees up resources for survival. Remarkably, however, the disruption of molecular signaling pathways that regulate ageing increases lifespan without the obligatory reduction in fecundity, thus challenging the key role of the survival-reproduction trade-off. Here, we review the diverse literature on the costs of lifespan extension and suggest that the current paradigm is overly centered on the trade-off between lifespan and fecundity, often neglecting key aspects of fitness, such as development time, defense against parasites and, in particular, the high costs of germline maintenance. Compromised germline maintenance increases germline mutation rate, which reduces offspring fitness and ultimately can terminate germline proliferation across generations. We propose that future work should incorporate the costs of germline maintenance in the study of ageing evolution, as well as in applied biomedical research, by assessing offspring fitness.

  • 17.
    Maklakov, Alexei A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kolm, Niclas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Brains and the city: big-brained passerine birds succeed in urban environments2011Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 7, nr 5, s. 730-732Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Urban regions are among the most human-altered environments on Earth and they are poised for rapid expansion following population growth and migration. Identifying the biological traits that determine which species are likely to succeed in urbanized habitats is important for predicting global trends in biodiversity. We provide the first evidence for the intuitive yet untested hypothesis that relative brain size is a key factor predisposing animals to successful establishment in cities. We apply phylogenetic mixed modelling in a Bayesian framework to show that passerine species that succeed in colonizing at least one of 12 European cities are more likely to belong to big-brained lineages than species avoiding these urban areas. These data support findings linking relative brain size with the ability to persist in novel and changing environments in vertebrate populations, and have important implications for our understanding of recent trends in biodiversity.

  • 18.
    Maklakov, Alexei A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Gonzalez-Voyer, Alejandro
    Rönn, Johanna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Kolm, Niclas
    Brains and the city in passerine birds: re-analysis and confirmation of the original result2013Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 6, s. 20130859-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Our original paper [1] included two Bayesian analyses [2] of the association between brain size and the probability of a passerine species of bird breeding in the city centre—at the level of families and at the level of individual species—with both analyses suggesting the same pattern. It has since been brought to our attention that in one of the analyses at the level of individual species, the residual variance was not fixed to 1 resulting in overestimation of the variance. We re-ran the analysis using fixed residual variance and the results support the original conclusion that relative brain size is associated with breeding in the city centre (ln brain size: posterior mean, 324.53, 95% credibility interval, 52.61–601.35; ln body size: posterior mean, −276.22, 95% credibility interval, −490.60 to −70.32). Furthermore, we applied a complimentary approach using logistic regression to test whether brain size predicts breeding in the city centre (yes/no) without accounting for phylogeny. This analysis also resulted in a significant positive association between brain size and breeding in city centres (likelihood ratio tests: ln brain size: d.f. = 1, χ2 = 11.08, p = 0.0009; ln body size: d.f. = 1, χ2 = 11.26, p = 0.0008). Thus, our results are confirmed by both phylogenetic and non-phylogenetic analyses.

  • 19.
    Maklakov, Alexei A.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Lövlie, Hanne
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Flis, Ilona
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Friberg, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    The effect of sexual harassment on lethal mutation rate in female Drosophila melanogaster2013Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 280, nr 1750, s. 20121874-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The rate by which new mutations are introduced into a population may have far-reaching implications for processes at the population level. Theory assumes that all individuals within a population have the same mutation rate, but this assumption may not be true. Compared with individuals in high condition, those in poor condition may have fewer resources available to invest in DNA repair, resulting in elevated mutation rates. Alternatively, environmentally induced stress can result in increased investment in DNA repair at the expense of reproduction. Here, we directly test whether sexual harassment by males, known to reduce female condition, affects female capacity to alleviate DNA damage in Drosophila melanogaster fruitflies. Female gametes can repair double-strand DNA breaks in sperm, which allows manipulating mutation rate independently from female condition. We show that male harassment strongly not only reduces female fecundity, but also reduces the yield of dominant lethal mutations, supporting the hypothesis that stressed organisms invest relatively more in repair mechanisms. We discuss our results in the light of previous research and suggest that social effects such as density and courtship can play an important and underappreciated role in mediating condition-dependent mutation rate.

  • 20.
    Nieuwenhuis, Bart P. S.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    The evolution of mating-type switching for reproductive assurance2016Ingår i: Bioessays, ISSN 0265-9247, E-ISSN 1521-1878, Vol. 38, nr 11, s. 1141-1149Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Alternative ways to ensure mate compatibility, such as hermaphroditism and the breakdown of self-incompatibility, evolved repeatedly when finding a mating partner is difficult. In a variety of microorganisms where compatibility is determined by mating-types, a highly regulated form of universal compatibility system called mating-type switching has evolved several times. This sophisticated system allows for the genetic adjustment of the mating type during asexual growth, and it most likely evolved for reproductive assurance of immotile species under low densities. In this review, we compare the switching strategy to other universal compatibility systems such as unisexual mating and homothallism. We identify the costs of switching, including genome instability, and mechanistic costs, as well as the benefits, mainly the maintenance of important mating-type functions. Given the potential benefits of mating-type switching, we speculate that switching is likely to have evolved many times independently, and may be more common in groups where genetic mating types regulate mate compatibility than assumed so far.

  • 21.
    Otto, Sarah P.
    et al.
    Univ British Columbia, Dept Zool, Vancouver, BC V6T 1Z4, Canada.;Univ British Columbia, Biodivers Res Ctr, Vancouver, BC V6T 1Z4, Canada..
    Scott, Michael F.
    Univ British Columbia, Biodivers Res Ctr, Vancouver, BC V6T 1Z4, Canada.;Univ British Columbia, Dept Bot, Vancouver, BC V6T 1Z4, Canada..
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Evolution of haploid selection in predominantly diploid organisms2015Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 112, nr 52, s. 15952-15957Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Diploid organisms manipulate the extent to which their haploid gametes experience selection. Animals typically produce sperm with a diploid complement of most proteins and RNA, limiting selection on the haploid genotype. Plants, however, exhibit extensive expression in pollen, with actively transcribed haploid genomes. Here we analyze models that track the evolution of genes that modify the strength of haploid selection to predict when evolution intensifies and when it dampens the "selective arena" within which male gametes compete for fertilization. Considering deleterious mutations, evolution leads diploid mothers to strengthen selection among haploid sperm/pollen, because this reduces the mutation load inherited by their diploid offspring. If, however, selection acts in opposite directions in haploids and diploids ("ploidally antagonistic selection"), mothers evolve to reduce haploid selection to avoid selectively amplifying alleles harmful to their offspring. Consequently, with maternal control, selection in the haploid phase either is maximized or reaches an intermediate state, depending on the deleterious mutation rate relative to the extent of ploidally antagonistic selection. By contrast, evolution generally leads diploid fathers to mask mutations in their gametes to the maximum extent possible, whenever masking (e.g., through transcript sharing) increases the average fitness of a father's gametes. We discuss the implications of this maternal-paternal conflict over the extent of haploid selection and describe empirical studies needed to refine our understanding of haploid selection among seemingly diploid organisms.

  • 22. Parker, G. A.
    et al.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Pitnick, S.
    Birkhead, T. R.
    Sperm competition games: Sperm size (mass) and number under raffle and displacement, and the evolution of P-22010Ingår i: Journal of Theoretical Biology, ISSN 0022-5193, E-ISSN 1095-8541, Vol. 264, nr 3, s. 1003-1023Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We examine models for evolution of sperm size (i.e. mass m) and number (s) under three mechanisms of sperm competition at low 'risk' levels: (i) raffle with no constraint on space available for competing sperm, (ii) direct displacement mainly by seminal fluid, and (iii) direct displacement mainly by sperm mass. Increasing sperm mass increases a sperm's 'competitive weight' against rival sperm through a diminishing returns function, r(m). ESS total ejaculate expenditure (the product m*s*) increases in all three models with sperm competition risk, q. If r(m), or ratio r'(m)/r(m), is independent of ESS sperm numbers, ESS sperm mass remains constant, and the sperm mass/number ratio (m*/s*) therefore decreases with risk. Dependency of sperm mass on risk can arise if r(m) depends on competing sperm density (sperm number / space available for sperm competition). Such dependencies generate complex relationships between sperm mass and number with risk, depending both on the mechanism and how sperm density affects r(m). While numbers always increase with risk, mass can either increase or decrease, but m*/s* typically decreases with risk unless sperm density strongly influences r(m). Where there is no extrinsic loading due to mating order, ESS paternity of the second (i.e. last) male to mate (P-2) under displacement always exceeds 0.5, and increases with risk (in the raffle P-2 = 0.5). Caution is needed when seeking evidence for a sperm size-number trade off. Although size and number trade-off independently against effort spent on acquiring matings, their product, m*s*, is invariant or fixed at a given risk level, effectively generating a size-number trade off. However, unless controlled for the effects of risk, the relation between m* and s* can be either positive or negative (a positive relation is usually taken as evidence against a size-number trade off).

  • 23.
    Silva, Willian T. A. F.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Sáez-Espinosa, Paula
    Department of Biotechnology, University of Alicante, Alicante, Spain.
    Torrijo-Boix, Stéphanie
    Department of Biotechnology, University of Alicante, Alicante, Spain.
    Romero, Alejandro
    Department of Biotechnology, University of Alicante, Alicante, Spain.
    Devaux, Caroline
    School of Biological Sciences, University of East Anglia, Norwich, UK.
    Durieux, Mathilde
    School of Biological Sciences, University of East Anglia, Norwich, UK.
    Gómez-Torres, María José
    Department of Biotechnology, University of Alicante, Alicante, Spain;Cátedra Human Fertility, University of Alicante, Alicante, Spain.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. School of Biological Sciences, University of East Anglia, Norwich, UK.
    The effects of male social environment on sperm phenotype and genome integrity2019Ingår i: Journal of Evolutionary Biology, ISSN 1010-061X, E-ISSN 1420-9101, Vol. 32, nr 6, s. 535-544Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sperm function and quality are primary determinants of male reproductive performance and hence fitness. The presence of rival males has been shown to affect ejaculate and sperm traits in a wide range of taxa. However, male physiological conditions may not only affect sperm phenotypic traits but also their genetic and epigenetic signatures, affecting the fitness of the resulting offspring. We investigated the effects of male-male competition on sperm quality using TUNEL assays and geometric morphometrics in the zebrafish, Danio rerio. We found that the sperm produced by males exposed to high male-male competition had smaller heads but larger midpiece and flagellum than sperm produced by males under low competition. Head and flagella also appeared less sensitive to the osmotic stress induced by activation with water. In addition, more sperm showed signals of DNA damage in ejaculates of males under high competition. These findings suggest that the presence of a rival male may have positive effects on sperm phenotypic traits but negative effects on sperm DNA integrity. Overall, males facing the presence of rival males may produce faster swimming and more competitive sperm but this may come at a cost for the next generation.

  • 24.
    Zajitschek, Susanne
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England.;CSIC, EBD, Donana Biol Stn, C Americo Vespucio S-N, Seville 41092, Spain..
    Herbert-Read, James E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen, Tillämpad matematik och statistik. Stockholm Univ, Dept Zool, S-10691 Stockholm, Sweden..
    Abbasi, Nasir M.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England.
    Zajitschek, Felix
    Monash Univ, Sch Biol Sci, Bldg 18, Clayton, Vic 3800, Australia..
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi. Univ East Anglia, Sch Biol Sci, Norwich Res Pk, Norwich NR4 7TJ, Norfolk, England.
    Paternal personality and social status influence offspring activity in zebrafish2017Ingår i: BMC Evolutionary Biology, ISSN 1471-2148, E-ISSN 1471-2148, Vol. 17, artikel-id 157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Evidence for the transmission of non-genetic information from father to offspring is rapidly accumulating. While the impact of chemical and physical factors such as toxins or diet on the fitness of the parents and their offspring have been studied extensively, the importance of behavioural and social circumstances has only recently been recognised. Behavioural traits such as personality characteristics can be relatively stable, and partly comprise a genetic component but we know little about the non-genetic transmission of plastic behavioural traits from parents to offspring. We investigated the relative effect of personality and of social dominance as indicators at the opposite ends of the plasticity range on offspring behaviour in the zebrafish (Danio rerio). We assessed male boldness, a behavioural trait that has previously been shown previously to possess genetic underpinnings, and experimentally manipulated male social status to assess the association between the two types of behaviour and their correlation with offspring activity. Results: We found a clear interaction between the relatively stable and putative genetic effects based on inherited differences in personality and the experimentally induced epigenetic effects from changes in the social status of the father on offspring activity. Conclusions: Our study shows that offspring behaviour is determined by a combination of paternal personality traits and on-genetic effects derived from the social status of the father.

  • 25.
    Zajitschek, Susanne
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik.
    Hotzy, Cosima
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Zajitschek, Felix
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Short-term variation in sperm competition causes sperm-mediated epigenetic effects on early offspring performance in the zebrafish2014Ingår i: Proceedings of the Royal Society of London. Biological Sciences, ISSN 0962-8452, E-ISSN 1471-2954, Vol. 281, nr 1785, s. 20140422-Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The inheritance of non-genetic factors is increasingly seen to play a major role in ecology and evolution. While the causes and consequences of epigenetic effects transmitted from the mother to the offspring have received ample attention, much less is known about how variation in the condition of the father affects the offspring. Here, we manipulated the intensity of sperm competition experienced by male zebrafish Danio rerio to investigate the potential for sperm-mediated epigenetic effects over a relatively short period of time. We found that the rapid responses of males to varying intensity of sperm competition not only affected sperm traits as shown previously, but also the performance of the resulting offspring. We observed that males exposed to high intensity of sperm competition produced faster swimming and more motile sperm, and sired offspring that hatched over a narrower time frame but exhibited a lower survival rate than males exposed to low intensity of sperm competition. Our results provide striking evidence for short-term paternal effects and the possible fitness consequences of such sperm-mediated non-genetic factors not only for the resulting offspring but also for the female.

  • 26.
    Ålund, Murielle
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Immler, Simone
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Evolutionsbiologi.
    Rice, Amber M.
    Qvarnström, Anna
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Zooekologi.
    Low fertility of wild hybrid male flycatchers despite recent divergence2013Ingår i: Biology Letters, ISSN 1744-9561, E-ISSN 1744-957X, Vol. 9, nr 3, artikel-id 20130169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Postzygotic isolation may be important for maintaining species boundaries, particularly when premating barriers are incomplete. Little is known about the course of events leading from minor environmental mismatches affecting hybrid fitness to severe genetic incompatibilities causing sterility or inviability. We investigated whether reduced reproductive success of hybrid males was caused by suboptimal sperm traits or by more severe genetic incompatibilities in a hybrid zone of pied (Ficedula hypoleuca) and collared flycatchers (F. albicollis) on the island of Oland, Sweden. About 4 per cent hybridization is observed in this population and all female hybrids are sterile. We found no sperm in the ejaculates of most sampled hybrid males, and sperm with abnormal morphology in two hybrids. Furthermore, none of the hybrids sired any offspring because of high levels of hatching failure and extra-pair paternity in their nests. These results from a natural hybrid zone suggest that the spermatogenesis of hybrid males may become disrupted despite little genetic divergence between the parental species.

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