Empirical Evidence for Son-Killing X Chromosomes and the Operation of SA-Zygotic Drive
2011 (English)In: PLoS ONE, ISSN 1932-6203, Vol. 6, no 8, e23508- p.Article in journal (Refereed) Published
Background: Diploid organisms have two copies of all genes, but only one is carried by each haploid gamete and diploid offspring. This causes a fundamental genetic conflict over transmission rate between alternative alleles. Single genes, or gene clusters, only rarely code for the complex phenotypes needed to give them a transmission advantage (drive phenotype). However, all genes on a male's X and Y chromosomes co-segregate, allowing different sex-linked genes to code for different parts of the drive phenotype. Correspondingly, the well-characterized phenomenon of male gametic drive, occurring during haploid gametogenesis, is especially common on sex chromosomes. The new theory of sexually antagonistic zygotic drive of the sex chromosomes (SA-zygotic drive) extends the logic of gametic drive into the diploid phase of the lifecycle, whenever there is competition among siblings or harmful sib-sib mating. The X and Y are predicted to gain a transmission advantage by harming offspring of the sex that does not carry them. Results: Here we analyzed a mutant X-chromosome in Drosophila simulans that produced an excess of daughters when transmitted from males. We developed a series of tests to differentiate between gametic and SA-zygotic drive, and provide multiple lines of evidence that SA-zygotic drive is responsible for the sex ratio bias. Driving sires produce about 50% more surviving daughters than sons. Conclusion: Sex-ratio distortion due to genetic conflict has evolved via gametic drive and maternally transmitted endosymbionts. Our data indicate that sex chromosomes can also drive by harming the non-carrier sex of offspring.
Place, publisher, year, edition, pages
2011. Vol. 6, no 8, e23508- p.
IdentifiersURN: urn:nbn:se:uu:diva-158594DOI: 10.1371/journal.pone.0023508ISI: 000294121300054OAI: oai:DiVA.org:uu-158594DiVA: diva2:440344