Title | Rainfall-driven sex-ratio genes in African buffalo suggested by correlations between Y-chromosomal haplotype frequencies and foetal sex ratio. |
Publication Type | Journal Article |
Year of Publication | 2010 |
Authors | van Hooft, P, Prins, HHT, Getz, WM, Jolles, AE, van Wieren, SE, Greyling, BJ, van Helden, PD, Bastos, ADS |
Journal | BMC Evol Biol |
Volume | 10 |
Pagination | 106 |
Date Published | 2010 Apr 23 |
ISSN | 1471-2148 |
Keywords | Animals, Buffaloes, Climate, Female, Fetus, Haplotypes, Male, Microsatellite Repeats, Sex Ratio, South Africa, Y Chromosome |
Abstract | BACKGROUND: The Y-chromosomal diversity in the African buffalo (Syncerus caffer) population of Kruger National Park (KNP) is characterized by rainfall-driven haplotype frequency shifts between year cohorts. Stable Y-chromosomal polymorphism is difficult to reconcile with haplotype frequency variations without assuming frequency-dependent selection or specific interactions in the population dynamics of X- and Y-chromosomal genes, since otherwise the fittest haplotype would inevitably sweep to fixation. Stable Y-chromosomal polymorphism due one of these factors only seems possible when there are Y-chromosomal distorters of an equal sex ratio, which act by negatively affecting X-gametes, or Y-chromosomal suppressors of a female-biased sex ratio. These sex-ratio (SR) genes modify (suppress) gamete transmission in their own favour at a fitness cost, allowing for stable polymorphism. RESULTS: Here we show temporal correlations between Y-chromosomal haplotype frequencies and foetal sex ratios in the KNP buffalo population, suggesting SR genes. Frequencies varied by a factor of five; too high to be alternatively explained by Y-chromosomal effects on pregnancy loss. Sex ratios were male-biased during wet and female-biased during dry periods (male proportion: 0.47-0.53), seasonally and annually. Both wet and dry periods were associated with a specific haplotype indicating a SR distorter and SR suppressor, respectively. CONCLUSIONS: The distinctive properties suggested for explaining Y-chromosomal polymorphism in African buffalo may not be restricted to this species alone. SR genes may play a broader and largely overlooked role in mammalian sex-ratio variation. |
DOI | 10.1186/1471-2148-10-106 |
Alternate Journal | BMC Evol Biol |
PubMed ID | 20416038 |
PubMed Central ID | PMC2875233 |
Grant List | GM83863 / GM / NIGMS NIH HHS / United States |