title: The fragile Y hypothesis: Y chromosome aneuploidy as a selective pressure in sex chromosome and meiotic mechanism evolution.
abstract: Loss of the Y-chromosome is a common feature of species with chromosomal sex determination. However, our understanding of why some lineages frequently lose Y-chromosomes while others do not is limited. The fragile Y hypothesis proposes that in species with chiasmatic meiosis the rate of Y-chromosome aneuploidy and the size of the recombining region have a negative correlation. The fragile Y hypothesis provides a number of novel insights not possible under traditional models. Specifically, increased rates of Y aneuploidy may impose positive selection for (i) gene movement off the Y; (ii) translocations and fusions which expand the recombining region; and (iii) alternative meiotic segregation mechanisms (achiasmatic or asynaptic). These insights as well as existing evidence for the frequency of Y-chromosome aneuploidy raise doubt about the prospects for long-term retention of the human Y-chromosome despite recent evidence for stable gene content in older non-recombining regions.
authors.affiliation: Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
authors.forename: Heath
authors.initials: H
authors.lastname: Blackmon
authors.affiliation: Department of Biology, University of Texas at Arlington, Arlington, TX, USA.
authors.forename: Jeffery P
authors.initials: JP
authors.lastname: Demuth
mesh_terms: D000782:Aneuploidy; D005075:Biological Evolution; D041322:Chromosomes, Human, Y / Q000235:genetics*; D006801:Humans; D008540:Meiosis; D008954:Models, Biological; D012641:Selection, Genetic; D012730:Sex Chromosomes / Q000235:genetics*
keywords: Turner syndrome; Y-chromosome loss; achiasmatic meiosis; aneuploidy; fragile Y; sex chromosome evolution