جهت دسترسی به کاربرگه ی زیر، از این لینک استفاده کنید. http://192.168.1.35:80/jspui/handle/1842/693
Title: Reduced adaptation of a non-recombining neo-Y chromosome
Authors: Bachtrog, Doris;Charlesworth, Brian
Keywords: Reduced
Adaptation
non-recombining
neo-Y
chromosome
Drosophila miranda
Issue Date: 9-Feb-2005
Publisher: Nature Publishing Group
Description: Sex chromosomes are generally believed to have descended from a pair of homologous autosomes. Suppression of recombination between the ancestral sex chromosomes led to the genetic degeneration of the Y chromosome1. In response, the X chromosome may become dosage-compensated1,2. Most proposed mechanisms for the degeneration of Y chromosomes involve the rapid fixation of deleterious mutations on the Y1. Alternatively, Y-chromosome degeneration might be a response to a slower rate of adaptive evolution, caused by its lack of recombination3. Here we report patterns of DNA polymorphism and divergence at four genes located on the neo-sex chromosomes of Drosophila miranda. We show that a higher rate of protein sequence evolution of the neo- X-linked copy of Cyclin B relative to the neo-Y copy is driven by positive selection, which is consistent with the adaptive hypothesis for the evolution of the Y chromosome3. In contrast, the neo- Y-linked copies of even-skipped and roundabout show an elevated rate of protein evolution relative to their neo-X homologues, probably reflecting the reduced effectiveness of selection against deleterious mutations in a non-recombining genome1.Our results provide evidence for the importance of sexual recombination for increasing and maintaining the level of adaptation of a population.
URI: http://192.168.1.35:80/jspui/handle/1842/693
Other Identifiers: Bachtrog D, Charlesworth B, NATURE, 416 (6878): 323-326 MAR 21 2002
http://hdl.handle.net/1842/693
Type Of Material: Article
Appears in Collections:School of Biological Sciences

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