Griffin, D.K. and Harvey, S.C. and Campos-Ramos, R. and Ayling, L.J. and Bromage, N.R. and Masabanda, J.S. and Penman, D.J. (2002) Early origins of the X and Y chromosomes: lessons from tilapia. Cytogenetic and Genome Research, 99 (1-4). pp. 157-163. ISSN 1424-8581.
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Differentiated sex chromosome pairs in diverse species display certain common characteristics, normally comprising one largely heterochromatic genetically inactive chromosome and one euchromatic genetically active chromosome (e.g. the mammalian Y and X respectively). It is widely accepted that dimorphic sex chromosomes evolved from homologous pairs of autosomes. Although the exact mechanisms through which the pair diverged are not fully understood, an initial suppression of recombination in the sex-determining region is required by all of the major theories. Here we address the question of the mechanism by which this initial suppression of recombination occurs. Our model postulates that the stochastic, de novo accumulation of heterochromatin in the sex determining region can delay pairing of the sex chromosomes in meiosis, resulting in a decrease in recombination. Data to support this model is presented from the cichlid fish, Oreochromis niloticus. Although such a decrease would in most circumstances be evolutionarily disadvantageous, if the region concerned included the major sex determining gene and other gene(s) with sex-specific functions, then this would be selectively advantageous and could trigger the process(es) which, ultimately, lead to the differentiation of the sex chromosomes.
|Additional information:||12900559 1424-859X|
|Uncontrolled keywords:||Animals Evolution, Molecular Female Heterochromatin In Situ Hybridization, Fluorescence Male Models, Genetic Synaptonemal Complex Tilapia Variation (Genetics) X Chromosome Y Chromosome|
|Divisions:||Faculties > Science Technology and Medical Studies > School of Biosciences|
|Depositing User:||Darren Griffin|
|Date Deposited:||24 Sep 2008 12:12|
|Last Modified:||03 Mar 2009 11:56|
|Resource URI:||http://kar.kent.ac.uk/id/eprint/12469 (The current URI for this page, for reference purposes)|
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