Extreme heterochiasmy and nascent sex chromosomes in European tree frogs.

Autor: Laura Berset-Brändli, Julie Jaquiéry, Thomas Broquet, Yuko Ulrich, Nicolas Perrin
Předmět:
Zdroj: Proceedings of the Royal Society B: Biological Sciences; Jul2008, Vol. 275 Issue 1642, p1577-1585, 9p
Abstrakt: We investigated sex-specific recombination rates in Hyla arborea, a species with nascent sex chromosomes and male heterogamety. Twenty microsatellites were clustered into six linkage groups, all showing suppressed or very low recombination in males. Seven markers were sex linked, none of them showing any sign of recombination in males (r=0.00 versus 0.43 on average in females). This opposes classical models of sex chromosome evolution, which envision an initially small differential segment that progressively expands as structural changes accumulate on the Y chromosome. For autosomes, maps were more than 14 times longer in females than in males, which seems the highest ratio documented so far in vertebrates. These results support the pleiotropic model of Haldane and Huxley, according to which recombination is reduced in the heterogametic sex by general modifiers that affect recombination on the whole genome. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index