Laboratory of Evolutionary Anthropology and Health, Binghamton University, Binghamton, New York, United States of America.
PLoS One. 2010 Nov 30;5(11):e14162. doi: 10.1371/journal.pone.0014162.
Human sexual behavior is highly variable both within and between populations. While sex-related characteristics and sexual behavior are central to evolutionary theory (sexual selection), little is known about the genetic bases of individual variation in sexual behavior. The variable number tandem repeats (VNTR) polymorphism in exon III of the human dopamine D4 receptor gene (DRD4) has been correlated with an array of behavioral phenotypes and may be predicatively responsible for variation in motivating some sexual behaviors, particularly promiscuity and infidelity.
METHODOLOGY/PRINCIPAL FINDINGS: We administered an anonymous survey on personal history of sexual behavior and intimate relationships to 181 young adults. We also collected buccal wash samples and genotyped the DRD4 VNTR. Here we show that individuals with at least one 7-repeat allele (7R+) report a greater categorical rate of promiscuous sexual behavior (i.e., having ever had a "one-night stand") and report a more than 50% increase in instances of sexual infidelity.
CONCLUSIONS/SIGNIFICANCE: DRD4 VNTR genotype varies considerably within and among populations and has been subject to relatively recent, local selective pressures. Individual differences in sexual behavior are likely partially mediated by individual genetic variation in genes coding for motivation and reward in the brain. Conceptualizing these findings in terms of r/K selection theory suggests a mechanism for selective pressure for and against the 7R+ genotype that may explain the considerable global allelic variation for this polymorphism.
人类性行为在个体和群体之间都存在高度的可变性。尽管与性相关的特征和性行为是进化理论（性选择）的核心，但人们对性行为个体差异的遗传基础知之甚少。人类多巴胺 D4 受体基因（DRD4）外显子 III 中的可变数目串联重复（VNTR）多态性与一系列行为表型相关联，并且可能是预测某些性行为（尤其是滥交和不忠）动机变化的原因。
方法/主要发现：我们对 181 名年轻人进行了关于性行为和亲密关系个人史的匿名调查。我们还收集了口腔洗液样本并对 DRD4 VNTR 进行了基因分型。在这里，我们表明至少有一个 7 重复等位基因（7R+）的个体报告了更高的滥交性行为（即曾经有过“一夜情”）的分类率，并报告了性不忠的发生率增加了 50%以上。
结论/意义：DRD4 VNTR 基因型在个体和群体之间存在很大差异，并受到相对近期的局部选择压力的影响。性行为的个体差异可能部分由大脑中编码动机和奖励的基因的个体遗传变异介导。根据 r/K 选择理论来理解这些发现，为针对和反对 7R+基因型的选择压力提供了一种机制，这可能解释了这种多态性在全球范围内的显著等位基因变异。
