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生物表型的影响存在显著差异。传入野生环境的家养性状通常会受到负选择。但存在例外情况：若家养动物的基因可提升野生种群的繁殖力，则这一公理可能不再适用。我们以赖特种群间选择模型（Wright's interdemic selection model）为研究框架，分析了一例罕见的野猪种群案例，该模型可用于阐释野猪与家猪（二者均被定义为同类群（deme））之间的基因流。我们对62头妊娠野猪的MC1R基因与微卫星中性位点展开分析，以此作为杂交事件的分子标记；同时将MC1R基因上常见于家养品种的核苷酸突变与产仔数进行关联，以评估野生母猪的适合度。在排除体型与种系效应的干扰后，携带MC1R基因非同义突变的野生母猪产仔数显著更高。本研究结果直接表明，通过种群间基因流进入野生种群的人工选择性状，当且仅当其能够提升野生环境中的适合度时，方可绕过自然选择的筛选。