Mina N S, Sheldon B L, Yoo B H, Frankham R
Commonwealth Scientific and Industrial Research Organisation, Division of Animal Production, North Ryde, New South Wales, Australia.
Poult Sci. 1991 Sep;70(9):1864-72. doi: 10.3382/ps.0701864.
Levels of heterozygosity at six polymorphic protein marker loci were determined by electrophoresis in 24 lines of poultry, encompassing 17 White Leghorn inbred lines (WLI) (with inbreeding coefficients, F, ranging from .946 to .988), five Australorp inbred lines (AusI) (with F values ranging from .924 to .961), and two randombred lines (one White Leghorn and one Australorp). Fixation was observed at one locus in WLI lines, and at two loci in the AusI lines. Segregation at the other loci was observed in the inbred lines of the two breeds. Observed heterozygosity in the inbred lines markedly exceeded the expectations under inbreeding theory. In White Leghorns, reproductive fitnesses for heterozygotes were superior to homozygotes in the inbred lines, but not in the control. Consequently, natural selection operating through associative overdominance appears to be responsible for the higher than expected heterozygosities in the inbred lines.
通过电泳法测定了24个家禽品系中6个多态性蛋白质标记位点的杂合性水平，这些品系包括17个白来航近交系（WLI）（近交系数F在0.946至0.988之间）、5个澳洲黑近交系（AusI）（F值在0.924至0.961之间）以及2个随机交配系（一个白来航系和一个澳洲黑系）。在WLI品系的一个位点以及AusI品系的两个位点观察到了固定现象。在两个品种的近交系中，其他位点存在分离现象。近交系中观察到的杂合性显著超过了近交理论下的预期。在白来航鸡中，近交系中杂合子的繁殖适应性优于纯合子，但在对照中并非如此。因此，通过关联超显性起作用的自然选择似乎是近交系中杂合性高于预期的原因。
