title: The sex-specific region of sex chromosomes in animals and plants.
abstract: Our understanding of the evolution of sex chromosomes has increased greatly in recent years due to a number of molecular evolutionary investigations in divergent sex chromosome systems, and these findings are reshaping theories of sex chromosome evolution. In particular, the dynamics of the sex-determining region (SDR) have been demonstrated by recent findings in ancient and incipient sex chromosomes. Radical changes in genomic structure and gene content in the male specific region of the Y chromosome between human and chimpanzee indicated rapid evolution in the past 6 million years, defying the notion that the pace of evolution in the SDR was fast at early stages but slowed down overtime. The chicken Z and the human X chromosomes appeared to have acquired testis-expressed genes and expanded in intergenic regions. Transposable elements greatly contributed to SDR expansion and aided the trafficking of genes in the SDR and its X or Z counterpart through retrotransposition. Dosage compensation is not a destined consequence of sex chromosomes as once thought. Most X-linked microRNA genes escape silencing and are expressed in testis. Collectively, these findings are challenging many of our preconceived ideas of the evolutionary trajectory and fates of sex chromosomes.
authors: Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.
authors: Andrea R
authors: AR
authors: Gschwend
authors: Laura A
authors: LA
authors: Weingartner
authors: Richard C
authors: RC
authors: Moore
authors: Ray
authors: R
authors: Ming
mesh_terms: D000818:Animals; D022004:Chromosome Structures / Q000235:genetics* / Q000502:physiology; D032461:Chromosomes, Plant / Q000235:genetics* / Q000502:physiology; D004251:DNA Transposable Elements; D004303:Dosage Compensation, Genetic; D019143:Evolution, Molecular; D005260:Female; D014644:Genetic Variation; D006801:Humans; D008297:Male; D010944:Plants / Q000235:genetics; D012641:Selection, Genetic; D012729:Sex Chromosome Aberrations; D012730:Sex Chromosomes / Q000235:genetics* / Q000502:physiology; D019849:Sex Determination Processes; D013737:Testis / Q000166:cytology / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D004251:DNA Transposable Elements