uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Contrasting demographic history and population structure in Capsella rubella and Capsella grandiflora, two closely related species with different mating systems
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Functional Genomics.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Functional Genomics.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Biology.
Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Evolutionary Functional Genomics.
Show others and affiliations
2011 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 20, no 16, 3306-3320 p.Article in journal (Refereed) Published
Abstract [en]

Mating system and population history can both have large impacts on genetic diversity and population structure. Here, we use multilocus sequence data to investigate how these factors impact two closely related Brassicaceae species: the selfing Capsella rubella and the outcrossing C. grandiflora. To do this we have sequenced 16 loci in approximately 70 individuals from 7 populations of each species. Patterns of population structure differ strongly between the two species. In C. grandiflora we observe an isolation-by-distance pattern and identify three clearly delineated genetic groups. In C. rubella, where we estimate the selfing rate to 0.90-0.94, the pattern is less clear with some sampling populations forming separate genetic clusters while others are highly mixed. The two species also have highly divergent histories. In close agreement with previous studies, our analysis gives very strong support for a recent bottleneck (18,600 ya) in C. rubella, which most likely represents speciation from C. grandiflora. In C. grandiflora there is moderate support for the standard neutral model in 2 of 3 genetic clusters, while the third cluster shows evidence of weak expansion.  It is clear that mating system has an impact on these two species, for example affecting the level of genetic variation, genetic structure and potentially also the size of the bottleneck in C. rubella. However, our results also clearly show that a combination of past and present processes, some of which are not affected by mating system, are needed to explain the differences between C. rubella and C. grandiflora.

 

Place, publisher, year, edition, pages
2011. Vol. 20, no 16, 3306-3320 p.
Keyword [en]
selfing, Brassicaceae, genetic structure, genetic diversity
National Category
Biological Sciences
Identifiers
URN: urn:nbn:se:uu:diva-136767DOI: 10.1111/j.1365-294X.2011.05189.xISI: 000293750000003OAI: oai:DiVA.org:uu-136767DiVA: diva2:377475
Available from: 2010-12-14 Created: 2010-12-14 Last updated: 2017-12-11Bibliographically approved
In thesis
1. Demography and Polyploidy in Capsella
Open this publication in new window or tab >>Demography and Polyploidy in Capsella
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Studies of demography and population structure give insight into important evolutionary processes such as speciation and diversification. In the present work I perform such studies in the genus Capsella, which has three species: C. grandiflora, an outcrossing diploid, C. rubella a selfing diploid, and C. bursa-pastoris a selfing tetraploid. These three species make a good model system for evolutionary studies because they encompass two major plant evolutionary processes: mating system shifts and polyploidization. To conduct my studies I have gathered a large number of samples across the distributions of each species and scored them both phenotypically and genotypically: more specifically we measured flowering time and collected DNA sequence data.

In the tetraploid C. bursa-pastoris we applied an association mapping approach which takes population structure into account to search for genetic variation associated with variation in flowering time. Flowering time is an important and highly adaptive trait which is frequently subject to natural selection. We found evidence of association between flowering time and several single nucleotide polymorphisms (SNPs) within the flowering locus C (FLC) and cryptochrome 1 (CRY1). In the case of FLC these SNPs code for nonconsensus splice site variation in one of the two copies of the gene. The SNPs could potentially have functional consequences and our results imply that non-functionalization of duplicate genes could be an important source of phenotypic variation.

Using a novel coalescent based approach, we investigated the polyploid origin of C. bursa-pastoris and find evidence supporting a recent autopolyploid origin of this species. In the two diploid species, I use sequence data to investigate population structure and demographic history and to assess the effects of selfing on C. rubella. Observed patterns of population structure and genetic diversity in C. rubella can be explained by a combination of both demographic history and mating system. Observed patterns in C. grandiflora suggest that the investigated populations do not deviate strongly from the SNM, which has rarely been found in modern demographic studies.

Finally, we investigate the effect of sampling strategy on demographic inference. Extensive sampling both within and across our populations allow us to empirically test the effect of sampling strategy on demographic inference. We complement the empirical analysis with simulations and conclude that the effect of sampling strategy is in many cases weak compared with that of demographic events. Nevertheless, these effects are real and have the potential to lead to false inference and therefore sampling strategy should be carefully considered in demographic studies.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 39 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 795
Keyword
Approximate Bayesian Computation, Mating system, Brassicaceae, flowering time, genetic diversity, Evolution
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-136696 (URN)978-91-554-7979-4 (ISBN)
Public defence
2011-02-04, Zootissalen, Evolutionary biology centre, Villavägen 9, Uppsala, 10:00 (English)
Opponent
Supervisors
Note
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 725Available from: 2011-01-14 Created: 2010-12-14 Last updated: 2011-03-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Lascoux, Martin

Search in DiVA

By author/editor
Lascoux, Martin
By organisation
Evolutionary Functional GenomicsEvolutionary Biology
In the same journal
Molecular Ecology
Biological Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 644 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf