Gene discovery and comparative analysis of X-degenerate genes from the domestic cat Y chromosome

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• 作者：Alison J. Pearks Wilkerson ; Terje Raudsepp ; Tina Graves ; Derek Albracht ; Wesley Warren ; Bhanu P. Chowdhary ; Loren C. Skow ; William J. Murphy
• 关键词：Y chromosome ; Cat ; Physical map ; Gene evolution ; Evolutionary strata
• 刊名：Genomics
• 出版年：2008
• 出版时间：November 2008
• 年：2008
• 卷：92
• 期：5
• 页码：329-338
• 全文大小：1173 K

文摘

Mammalian sex chromosomes are the remnants of an ancient autosomal pair present in the ancestral mammalian karyotype. As a consequence of random decay and chromosome rearrangements over evolutionary time, Y chromosome gene repertoires differ between eutherian lineages. To investigate the gene repertoire and transcriptional analysis of the domestic cat Y chromosome, and their potential roles in spermatogenesis, we obtained full-length cDNA sequences for all known Y genes and their X chromosome gametologues and used those sequences to create a BAC-based physical map of the X-degenerate region. Our results indicate the domestic cat Y chromosome has retained most X-degenerate genes that were present on the ancestral eutherian Y chromosome. Transcriptional analysis revealed that most feline X-degenerate genes have retained housekeeping functions shared by their X chromosome partners and have not been specialized for testis-specific functions. Physical mapping data indicate that the cat SRY gene is present as multiple functional copies and that very little of the felid Y chromosome may be single copy. X-Y gene divergence time estimates obtained using Bayesian methods confirm an early origin of Stratum 1 genes prior to the origin of therian mammals. We observed no statistical difference in the ages of Stratum 2 and Stratum 3 gene pairs, suggesting that eutherian and marsupial Stratum 2 genes may have been independently retained in each lineage.