جهت دسترسی به کاربرگه ی زیر، از این لینک استفاده کنید.
|Title:||Reduced adaptation of a non-recombining neo-Y chromosome|
|Authors:||Bachtrog, Doris;Charlesworth, Brian|
|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.|
|Other Identifiers:||Bachtrog D, Charlesworth B, NATURE, 416 (6878): 323-326 MAR 21 2002|
|Type Of Material:||Article|
|Appears in Collections:||School of Biological Sciences|
Files in This Item:
There are no files associated with this item.
تمامی کاربرگه ها در کتابخانه ی دیجیتال حنان به صورت کامل محافظت می شوند.