A Molecular Quantitative Genetic Study of Epistasis and Its Evolutionary Role

小行星9419992 许多性状受到多个基因的影响。 研究这些基因之间的相互作用，上位性，对于理解这些复杂性状的遗传基础至关重要。 例如，基因相互作用可能会导致某些家庭发生疾病，但不会导致其他家庭发生疾病，这取决于这些家庭中的基因组。 上位性的程度对于小种群应对选择压力、避免灭绝或作为物种形成的一部分的灵活性也很重要。 将测量基因相互作用对小鼠成年体重的影响，然后将跟踪该相互作用对小种群动物之间遗传差异的影响。 标准的群体遗传学理论预测，当近亲繁殖发生在小群体中时，遗传差异会急剧下降，从而限制了它们的进化潜力。 然而，新的模型纳入上位性的影响预测只有轻微的下降，甚至增加遗传差异的水平，近亲繁殖。 两种近交系小鼠将进行杂交。 将从该杂交中获得50个小种群（4只动物）和2个大种群（100只动物）。 小鼠之间遗传差异的总体平均水平和由于先前鉴定的每个基因引起的差异将在大和小群体大小处理之间进行比较，并根据结合上位性的进化模型解释结果。

9419992 CHEVERUD Many traits are affected by multiple genes. Studying the interactions among these genes, epistasis, is essential for understanding the genetic basis for these complex traits. Gene interaction, for example, may cause a disease to occur in some families but not others depending on what sets of genes are in those families. The extent of epistasis is also important for the amount of flexibility available in small populations to respond to selective pressures, to avoid extinction or as part of speciation. The amount of gene interaction on adult body weight in mice will be measured and then the effects of that interaction on inherited differences between animals in small populations will be followed. Standard population genetic theory predicts a sharp decline in inherited differences as inbreeding occurs in small populations, thus limiting their evolutionary potential. However, new models incorporating the effects of epistasis predict only a slight decline, or even an increase in the level of inherited differences, with inbreeding. Two inbred strains of mice will be crossed. Fifty small populations (4 animals) and two large populations (100 animals) will be derived from this cross. The overall average level of inherited differences between mice and the differences due to each previously identified gene will be compared between the large and small population size treatments and the results interpreted in the light of evolutionary models incorporating epistasis.