Data from: The colour of paternity: extra-pair paternity in the wild Gouldian finch does not appear to be driven by genetic incompatibility between morphs

In socially monogamous species, individuals can use extra-pair paternity and offspring sex allocation as adaptive strategies to ameliorate costs of genetic incompatibility with their partner. Previous studies on domesticated Gouldian finches (Erythrura gouldiae) demonstrated a genetic incompatibility between head colour morphs, the effects of which are more severe in female offspring. Domesticated females use differential sex allocation, and extra-pair paternity with males of compatible head colour, to reduce fitness costs associated with incompatibility in mixed-morph pairings. However, laboratory studies are an oversimplification of the complex ecological factors experienced in the wild, and may only reflect the biology of a domesticated species. This study aimed to examine the patterns of parentage and sex-ratio bias with respect to colour pairing combinations in a wild population of the Gouldian finch. We utilized a novel PCR assay that allowed us to genotype the morph of offspring before the morph phenotype develops, and to explore bias in morph paternity and selection at the nest. Contrary to previous findings in the laboratory, we found no effect of pairing combinations on patterns of extra-pair paternity, offspring sex ratio, or selection on morphs in nestlings. In the wild, the effect of morph incompatibility is likely much smaller, or absent, than was observed in the domesticated birds. Furthermore, the previously studied domesticated population is genetically differentiated from the wild population, consistent with the effects of domestication. It is possible that the domestication process fostered the emergence (or enhancement) of incompatibility between colour morphs previously demonstrated in the laboratory.

在社会性一夫一妻制物种中，个体可借助婚外父权（extra-pair paternity）与后代性别分配（offspring sex allocation）策略，缓解与配偶间遗传不相容性带来的适合度代价。此前针对驯养七彩文鸟（Gouldian finch, *Erythrura gouldiae*）的研究已证实其头部色型（colour morph）间存在遗传不相容性，且该效应在雌性后代中更为显著。驯养雌性七彩文鸟会通过差异化性别分配，以及与头部色型相容的雄性开展婚外父权交配，以此降低混色型配对时因不相容性带来的适合度损失。
然而，实验室研究将野外复杂生态因子过度简化，仅能反映驯养物种的生物学特性。本研究旨在探究野生七彩文鸟种群中，配对组合与父权模式、性别比例偏差之间的关联。我们采用了一种新型聚合酶链式反应（PCR）检测方法，可在色型表型显现前对后代的色型进行基因分型，并借此探究父权的色型偏差与巢内选择情况。
与此前实验室研究结果相悖的是，本研究未发现配对组合对婚外父权模式、后代性别比例，或是雏鸟色型所受的选择作用存在任何影响。在野外环境中，色型不相容性的影响可能远小于驯养种群中观察到的结果，甚至可能不存在该效应。
此外，此前研究所用的驯养种群与野生种群存在遗传分化，这与驯养作用的效应相符。推测驯养过程可能催生（或增强了）此前实验室中所观测到的色型间不相容性。