Under inbreeding, heterozygosity at neutral genetic markers is likely to reflect genome-wide heterozygosity and, thus, is expected to correlate with fitness. There is, however, growing evidence that some of heterozygosity-fitness correlations (HFCs) can be explained by ‘local effects’, where noncoding loci are at linkage disequilibrium with functional genes. The aim of this study was to investigate correlations between heterozygosity at seven microsatellite loci and two fitness-related traits, nestling growth rate and nutritional condition, in a recently bottlenecked population of great cormorant Phalacrocorax carbo sinensis. We found that heterozygosity was positively associated with both nestling traits at the between-brood level, but the individual (within-brood) effects of heterozygosity were non-significant. We also found that only one locus per trait was primarily responsible for the significant multi-locus HFCs, suggesting a linkage disequilibrium with non-identified functional loci. The results give support for ‘local effect’ hypothesis, confirming that HFCs may not only be interpreted as evidence of inbreeding and that genetic associations between functional and selectively neutral markers could be much more common in natural populations than previously thought.

中文翻译：

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大Cor的局部杂合性对雏鸟生长和状况的影响。

在近交中，中性遗传标记处的杂合性可能反映了全基因组的杂合性，因此有望与适应性相关。但是，越来越多的证据表明，某些杂合度-适合度相关性（HFC）可以用“局部效应”解释，其中非编码基因座与功能基因处于连锁不平衡状态。这项研究的目的是调查最近great瓶颈的中华ala种群中七个微卫星基因座的杂合度与两个与健身相关的性状，雏鸟的生长速度和营养状况之间的相关性。。我们发现杂合性与育雏性状在亲代水平上呈正相关，但杂合性的个体（亲代内）影响并不显着。我们还发现，每个性状只有一个基因座主要负责显着的多基因座HFC，这表明与未知功能基因座的连锁不平衡。结果为“局部效应”假说提供了支持，证实了HFC不仅可以解释为近交证据，而且功能性标记和选择性中性标记之间的遗传关联在自然种群中可能比以前认为的更为普遍。