Inoue Eiji, Inoue-Murayama Miho, Vigilant Linda, Takenaka Osamu, Nishida Toshisada
Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Am J Phys Anthropol. 2008 Nov;137(3):256-62. doi: 10.1002/ajpa.20865.
In chimpanzees (Pan troglodytes), high-ranking males are expected to have high reproductive success and females typically emigrate upon reaching maturity. Although high average relatedness among males in the same social groups has been assumed, previous reports have indicated that relatedness among males is not necessarily significantly higher than that among females. The paternity of 11 offspring and the relatedness of 50 individuals in the M group of chimpanzees at Mahale Mountains National Park, Tanzania, were investigated using DNA analyses. We determined the fathers of 10 offspring. Two different alpha males sired a total of five offspring, whereas the other males had low reproductive success. The proportion of paternal half-sibling pairs among the 10 offspring was 15.6%. The average relatedness among mature males was significantly higher than that among mature females. The existence of an old male and the long tenure of one alpha male may have contributed to this significant difference. The average dyadic relatedness among mature natal individuals was significantly higher than that in natal-immigrant pairs in which the individuals came from different groups. The average relatedness among immigrant females was similar to that in pairs of natal and immigrant females, suggesting that the immigrants came from various groups. Thus, female transfer acts to maintain low average relatedness within the group. A comparison of our results to those from other study sites suggests that although the average relatedness among adult males does not reach the level of half-siblings, under some circumstances it can exceed the relatedness of females.
在黑猩猩（黑猩猩属）中，高等级雄性预计具有较高的繁殖成功率，而雌性通常在成熟后迁移。尽管假设同一社会群体中雄性之间的平均亲缘关系较高，但先前的报告表明，雄性之间的亲缘关系不一定显著高于雌性。利用DNA分析，对坦桑尼亚马哈勒山脉国家公园黑猩猩M组中11个后代的父系情况和50个个体的亲缘关系进行了调查。我们确定了10个后代的父亲。两个不同的首领雄性总共生育了5个后代，而其他雄性的繁殖成功率较低。在这10个后代中，父系半同胞对的比例为15.6%。成熟雄性之间的平均亲缘关系显著高于成熟雌性之间的平均亲缘关系。一只老年雄性的存在以及一位首领雄性的长期任期可能促成了这一显著差异。成熟出生个体之间的平均二元亲缘关系显著高于来自不同群体的出生-移民个体对中的平均二元亲缘关系。移民雌性之间的平均亲缘关系与出生和移民雌性对中的平均亲缘关系相似，这表明移民来自不同的群体。因此，雌性迁移有助于维持群体内较低的平均亲缘关系。将我们的结果与其他研究地点的结果进行比较表明，尽管成年雄性之间的平均亲缘关系未达到半同胞的水平，但在某些情况下，它可能超过雌性之间的亲缘关系。
