Mammalian Sex Chromosome Evolution

Although they are highly dissimilar in sequence content in extant organisms, the mammalian sex chromosomes (i.e. the X and Y) evolved from a pair of autosomes. Differentiation of the sex chromosomes during evolution was initiated by the suppression of X–Y recombination. This was followed by the general degeneration of genes on the Y-chromosome, with specific instances of gene specialization on the nonrecombining portion of the Y.

Keywords: X-chromosome; Y-chromosome; mammalian sex chromosomes; Y degeneration; pseudoautosomal region; nonrecombining Y

 References
    Crow J (1993) How much do we know about spontaneous human mutation rates? Environmental and Molecular Mutagenesis 21: 122–129.
    Foster JW and Graves JA (1994) An SRY-related sequence on the marsupial X chromosome: implications for the evolution of the mammalian testis-determining gene. Proceedings of the National Academy of Sciences of the USA 91: 1927–1931.
    Gavrilov LA, Gavrilova NS, Kroutko VN et al. (1997) Mutation load and human longevity. Mutation Research 377: 61–62.
    Graves JM, Wakefield MJ and Toder R (1998) The origin and evolution of the pseudoautosomal regions of human sex chromosomes. Molecular Genetics 7: 1991–1996.
    Handley LJ, Ceplitis H and Ellegren H (2004) Evolutionary strata on the chicken Z chromosome: implications for sex chromosome evolution. Genetics 167(1): 367–376.
    Hughes JF, Skaletsky H and Pyntikova T (2005) Conservation of Y-linked genes during human evolution revealed by comparative sequencing in chimpanzee. Nature 437(7055): 100–103.
    Lahn BT and Page DC (1997) Functional coherence of the human Y chromosome. Science 278: 675–680.
    Lahn BT and Page DC (1999a) Four evolutionary strata on the human X chromosome. Science 286: 964–967.
    Lahn BT and Page DC (1999b) Retroposition of autosomal mRNA yielded testis-specific gene family on human Y chromosome. Nature Genetics 21: 429–433.
    Malcom CM, Wyckoff GJ and Lahn BT (2003) Genic mutation rates in mammals: local similarity, chromosomal heterogeneity, and X-versus-autosome disparity. Molecular Biology and Evolution 20: 1633–1641.
    Muller HJ (1964) The relation of recombination to mutational advance. Mutation Research 1: 2–9.
    Pamilo P and Bianchi NO (1993) Evolution of the Zfx and Zfy genes: rates and interdependence between the genes. Molecular Biology and Evolution 10: 271–281.
    Rappold GA (1993) The pseudoautosomal regions of the human sex chromosomes. Human Genetics 92: 315–324.
    Rens W, O'Brien PC, Grutzner F et al. (2007) The multiple sex chromosomes of platypus and echidna are not completely identical and several share homology with the avian Z. Genome Biology 8(11): R243.
    Rice WR (1987) Genetic hitchhiking and the evolution of reduced genetic activity of the Y sex chromosome. Genetics 116: 161–167.
    Saxena R, Brown LG, Hawkins T et al. (1996) The DAZ gene cluster on the human Y chromosome arose from an autosomal gene that was transposed, repeatedly amplified and pruned. Nature Genetics 14: 292–299.
    Shen P, Wang F, Underhill P et al. (2000) Population genetic implications from sequence variation in four Y chromosome genes. Proceedings of the National Academy of Sciences of the USA 97: 7354–7359.
    Shimmin LC, Chang BH, Hewett-Emmett D and Li WH (1993) Potential problems in estimating the male-to-female mutation rate ratio from DNA sequence data. Journal of Molecular Evolution 37: 160–166.
    Skaletsky H, Kuroda-Kawaguchi T, Minx PJ et al. (2003) The male-specific region of the human Y chromosome is a mosaic of discrete sequence classes. Nature 423: 825–837.
    Stevanovic M, Lovell-Badge R, Collignon J and Goodfellow PN (1993) SOX3 is an X-linked gene related to SRY. Human Molecular Genetics 2: 2013–2018.
    Vallender EJ and Lahn BT (2004) How mammalian sex chromosomes acquired their peculiar gene content. BioEssays 26: 159–169.
    Wyckoff GJ, Li J and Wu CI (2002) Molecular evolution of functional genes on the mammalian Y chromosome. Molecular Biology and Evolution 19: 1633–1636.
    Yoshida K and Sugano S (1999) Identification of a novel protocadherin gene (PCDH11) on the human XY homology region in Xq21.3. Genomics 62: 540–543.
 Further Reading
    Charlesworth B (1991) The evolution of sex chromosomes. Science 251: 1030–1033.
    Delbridge ML, Lingenfeler PA, Disteche CM and Graves JAM (1999) The candidate spermatogenesis gene RBMY has a homologue on the human X chromosome. Nature Genetics 22: 223–224.
    Graves JA (1995) The origin and function of the mammalian Y chromosome and Y-borne genes – an evolving understanding. BioEssays 17: 311–320.
    Graves JA (2006) Sex chromosome specialization and degeneration in mammals. Cell 124: 901–914.
    Gvozdev VA, Kogan GL and Usakin LA (2005) The Y chromosome as a target for acquired and amplified genetic material in evolution. BioEssays 27(12): 1256–1262.
    Jegalian K and Page DC (1998) A proposed path by which genes common to mammalian X and Y chromosomes evolve to become X inactivated. Nature 394: 776–780.
    Kohn M, Kehrer-Sawatzki H, Vogel W, Graves JA and Hameister H (2004) Wide genome comparisons reveal the origins of the human X chromosome. Trends in Genetics 20: 598–603.
    Lahn BT, Pearson NM and Jegalian K (2001) The human Y chromosome, in the light of evolution. Nature Reviews. Genetics 2: 207–216.
    Mazeyrat S, Saut N, Mattei M and Mitchell MJ (1999) RBMY evolved on the Y chromosome from a ubiquitously transcribed X–Y identical gene. Nature Genetics 22: 224–226.
    Rice WR (1994) Degeneration of a nonrecombining chromosome. Science 263: 230–232.
    Vicoso B and Charlesworth B (2006) Evolution of the X chromosome: unusual patterns and processes. Nature Reviews. Genetics 7: 645–653.
Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

How to Cite close
Wyckoff, Gerald J, and Malcom, Christine M(Jul 2008) Mammalian Sex Chromosome Evolution. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0005792.pub2]