Positive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African buffalo: a plausible new mechanism for a high frequency anomaly

dc.contributor.authorVan Hooft, Pim
dc.contributor.authorGreyling, Barend Jacobus
dc.contributor.authorGetz, Wayne Marcus
dc.contributor.authorVan Helden, Paul David
dc.contributor.authorZwaan, Bas J.
dc.contributor.authorBastos, Armanda D.S.
dc.contributor.editorAnisimova, Maria
dc.date.accessioned2015-05-28T08:19:02Z
dc.date.available2015-05-28T08:19:02Z
dc.date.issued2014-11-05
dc.description.abstractAlthough generally rare, deleterious alleles can become common through genetic drift, hitchhiking or reductions in selective constraints. Here we present a possible new mechanism that explains the attainment of high frequencies of deleterious alleles in the African buffalo (Syncerus caffer) population of Kruger National Park, through positive selection of these alleles that is ultimately driven by a sex-ratio suppressor. We have previously shown that one in four Kruger buffalo has a Y-chromosome profile that, despite being associated with low body condition, appears to impart a relative reproductive advantage, and which is stably maintained through a sex-ratio suppressor. Apparently, this sex-ratio suppressor prevents fertility reduction that generally accompanies sex-ratio distortion. We hypothesize that this bodycondition- associated reproductive advantage increases the fitness of alleles that negatively affect male body condition, causing genome-wide positive selection of these alleles. To investigate this we genotyped 459 buffalo using 17 autosomal microsatellites. By correlating heterozygosity with body condition (heterozygosity-fitness correlations), we found that most microsatellites were associated with one of two gene types: one with elevated frequencies of deleterious alleles that have a negative effect on body condition, irrespective of sex; the other with elevated frequencies of sexually antagonistic alleles that are negative for male body condition but positive for female body condition. Positive selection and a direct association with a Y-chromosomal sex-ratio suppressor are indicated, respectively, by allele clines and by relatively high numbers of homozygous deleterious alleles among sex-ratio suppressor carriers. This study, which employs novel statistical techniques to analyse heterozygosity-fitness correlations, is the first to demonstrate the abundance of sexually-antagonistic genes in a natural mammal population. It also has important implications for our understanding not only of the evolutionary and ecological dynamics of sex-ratio distorters and suppressors, but also of the functioning of deleterious and sexuallyantagonistic alleles, and their impact on population viability.en_ZA
dc.description.librarianam2015en_ZA
dc.description.sponsorshipUS NIH/NSF Ecology of Infectious Disease Grant GM83863 awarded to WMG.en_ZA
dc.description.urihttp://www.plosone.orgen_ZA
dc.identifier.citationvan Hooft P, Greyling BJ, Getz WM, van Helden PD, Zwaan BJ & Bastos, ADS (2014) Positive Selection of Deleterious Alleles through Interaction with a Sex-Ratio Suppressor Gene in African Buffalo: A Plausible New Mechanism for a High Frequency Anomaly. PLoS ONE 9(11): e111778. DOI: 10.1371/journal.pone.0111778en_ZA
dc.identifier.issn1932-6203
dc.identifier.other10.1371/journal.pone.0111778
dc.identifier.urihttp://hdl.handle.net/2263/45318
dc.language.isoenen_ZA
dc.publisherPublic Library of Scienceen_ZA
dc.rights© 2014 van Hooft et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License.en_ZA
dc.subjectDeleterious allelesen_ZA
dc.subjectSex-ratio suppressoren_ZA
dc.subjectKruger National Park (South Africa)en_ZA
dc.subjectAfrican buffalo (Syncerus caffer)en_ZA
dc.titlePositive selection of deleterious alleles through interaction with a sex-ratio suppressor gene in African buffalo: a plausible new mechanism for a high frequency anomalyen_ZA
dc.typeArticleen_ZA

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