Data from: Three hundred years of low non-paternity in a human population

When cuckoldry is frequent we can expect fathers to withhold investment in offspring that may not be theirs. Human paternal investment can be substantial and is in line with observations from tens of thousands of conceptions that suggest that cuckoldry is rare in humans. The generality of this claim seems to be in question as the rate of cuckoldry varies across populations and studies have mostly been on Western populations. Two additional factors complicate our conclusions, 1) current estimates of the rate of cuckoldry in humans may not reflect our past behaviour as adultery can be concealed by the use of contraceptives; and 2) it is difficult to obtain samples that are random with respect to their paternity certainty. Studies that combine genealogies with Y-chromosome haplotyping are able to circumvent some of these problems by probing into humans' historical behaviour. Here we use this approach to investigate 1273 conceptions over a period of 330 years in 24 families of the Afrikaner population in South Africa. We use haplotype frequency and diversity and coalescent simulations to show that the male population did not undergo a severe bottleneck and that paternity exclusion rates are high for this population. The rate of cuckoldry in this Western population was 0.9% (95%CI 0.4 - 1.5%) and we argue that given the current data on historical populations we have to conclude that, at least for Western human populations, cuckoldry rate is probably in the range of 1%.

当婚外生育（cuckoldry）频发时，我们可以预期父亲会减少对可能并非亲生的后代的抚育投入。人类的父代抚育投入规模可观，且结合数万次妊娠的观测结果来看，人类的婚外生育现象较为罕见。不过这一结论的普适性似乎存在争议：不同人群的婚外生育比例存在差异，且现有研究大多聚焦于西方人群。另有两个额外因素令相关结论愈发复杂：其一，当前人类婚外生育比例的估算值或许无法反映我们的过往行为，因为避孕手段的使用会掩盖通奸行为；其二，很难获取与父权确定性无关的随机样本。将家谱数据与Y染色体单倍型分型（Y-chromosome haplotyping）相结合的研究，能够通过探究人类的历史行为规避部分此类问题。本研究采用该方法，对南非阿非利卡人（Afrikaner）族群24个家族跨越330年的1273次妊娠展开调查。我们借助单倍型频率、多样性数据以及溯祖模拟（coalescent simulations）证明，该男性群体未经历严重的种群瓶颈，且此人群的父权排除率较高。该西方人群的婚外生育比例为0.9%（95%置信区间，95%CI：0.4 - 1.5%），我们据此认为，结合当前针对历史人群的研究数据，至少就西方人类人群而言，婚外生育比例大概率处于1%左右的区间。