Data from: Does multiple paternity influence offspring disease-resistance?

It has been suggested that polyandry allows females to increase offspring genetic diversity and reduce the prevalence and susceptibility of their offspring to infectious diseases. We tested this hypothesis in wild-derived house mice (Mus musculus) by experimentally infecting the offspring from 15 single and 15 multiple sired litters with two different strains of a mouse pathogen (Salmonella Typhimurium) and compared their ability to control infection. We found high variation in individual infection resistance (measured with pathogen loads) and significant differences among families, suggesting genetic effects on Salmonella resistance, but we found no difference in prevalence or infection resistance between single versus multiple sired litters. We found a significant sex difference in infection resistance, but surprisingly, males were more resistant to infection than females. Also, infection resistance was correlated with weight loss during infection, though only for females, indicating that susceptibility to infection had more harmful health consequences for females than males. To our knowledge, our findings provide the first evidence for sex-dependent resistance to Salmonella infection in house mice. Our results do not support the hypothesis that multiple-sired litters are likely to survive infection than single-sired litters; however, as we explain, additional studies are required before ruling out this hypothesis.

有研究假说提出，一妻多夫制可使雌性个体提升后代的遗传多样性，并降低后代感染传染病的概率与易感性。我们以野生起源的小家鼠（Mus musculus）为研究对象，对该假说开展验证：通过实验感染的方式，用两种不同株型的鼠类病原体——鼠伤寒沙门氏菌（Salmonella Typhimurium），分别侵染15窝单父系幼崽与15窝多父系幼崽，随后比较二者的感染控制能力。研究结果显示，个体感染抗性（以病原体载量为衡量指标）存在较高水平的变异，且不同家系间存在显著差异，这表明遗传效应对鼠伤寒沙门氏菌抗性存在影响；但我们未发现单父系与多父系幼崽在感染发生率或感染抗性上存在显著差异。此外，我们观察到感染抗性存在显著的性别差异——令人意外的是，雄性个体的感染抗性强于雌性。同时，感染抗性与感染过程中的体重下降存在相关性，但该相关性仅存在于雌性个体中，这提示感染易感性对雌性个体的健康危害程度高于雄性。据我们所知，本研究首次在家鼠中发现了针对鼠伤寒沙门氏菌感染的性别依赖性抗性。我们的结果不支持“多父系幼崽较单父系幼崽更可能在感染中存活”的假说；但正如我们所阐释的，在完全排除该假说前仍需开展更多相关研究。