Data from: Unexpected but welcome. Artificially selected traits may increase fitness in wild boar

Artificial selection affects phenotypes differently by natural selection. Domestic traits, which pass into the wild, are usually negatively selected. Yet, exceptionally, this axiom may fail to apply if genes, from the domestic animals, increase fertility in the wild. We studied a rare case of a wild boar population under the framework of Wright's interdemic selection model, which could explain gene flow between wild boar and pig, both considered as demes. We analysed the MC1R gene and microsatellite neutral loci in 62 pregnant wild boars as markers of hybridization, and we correlated nucleotide mutations on MC1R (which are common in domestic breeds) to litter size, as an evaluation of fitness in wild sow. Regardless of body size and phyletic effects, wild boar sows bearing nonsynonymous MC1R mutations produced larger litters. This directly suggests that artificially selected traits reaching wild populations, through interdemic gene flow, could bypass natural selection if and only if they increase the fitness in the wild.

人工选择与自然选择对表型的影响存在显著差异。进入野生环境的家养性状通常会受到负选择。然而，存在例外情况：若家养动物的基因能够提升野生个体的繁殖力，则这一公理可能不再成立。我们基于赖特的种群间选择模型（Wright's interdemic selection model）开展研究，分析了一例罕见的野生野猪种群——该模型可用于解释被视作同类群的野猪与家猪之间的基因交流。我们以62只孕野猪为研究对象，对其MC1R基因与微卫星中性位点进行检测，以此作为杂交事件的标记；同时将MC1R基因上常见于家养品种的核苷酸突变与窝产仔数进行关联分析，以评估野生母猪的适合度。无论体型大小与系统发育效应如何，携带MC1R基因非同义突变的野生母猪均拥有更大的窝产仔数。这一结果直接表明：通过种群间基因交流进入野生种群的人工选择性状，唯有在提升野生种群适合度的前提下，才能够绕过自然选择的筛选。