Williams S, Verma M M, Jinks J L, Brasier C M
Heredity (Edinb). 1976 Dec;37(3):365-75. doi: 10.1038/hdy.1976.101.
Two extreme dikaryotic idolates chosen from a large sample of a localised population of Schizophyllum commune exhibited a considerable amount of genetical variation for growth rate at the near ambient temperature of 20 degrees C and at the higher temperature of 30 degrees C. The potential variation within these extreme isolates were greater than the variation observed in the whole sample. Regression analysis of the variation in growth rate of the dikaryotic progeny of the extreme isolates on that of their component monokaryons showed that the nature of gene action was not the same in these two stages of the life cycle. The simple additive-dominance model of gene action was adequate to explain the variation in growth rate in both of the extreme isolates at both of the temperatures. The small deviations from this model could be accounted for by unequal gene frequencies due to small sample size although a low incidence of non-allelic interactions could not be rule out. Directional dominance for growth rate was detected in both isolates at the more normal temperature and it was opposing in direction in the two isolates. In the slow growing isolate the dominance was for faster growth and in the fast growing isolate it was for slower growth. This is expected for a character which displays overall ambi-directional dominance if isolates with more extreme growth rates than those recovered in the population sample are eliminated by stabilising selection. The dominance is temperature dependent being ambi-directional in both isolates at the higher temperature. Environmental heterogeneity, the buffering effects of directional dominance and genotype-environment interactions and opposing selective forces operating on the monokaryotic and dikaryotic stages of the life cycle are possible contributory factors to the considerable free and potential variability displayed in this small, localised population.
从裂褶菌局部群体的大量样本中选出的两个极端双核同宗配合体，在接近环境温度20摄氏度和较高温度30摄氏度时，生长速率表现出相当大的遗传变异。这些极端分离物中的潜在变异大于整个样本中观察到的变异。对极端分离物的双核后代及其组成单核体的生长速率变异进行回归分析表明，在生命周期的这两个阶段，基因作用的性质并不相同。基因作用的简单加性-显性模型足以解释两个极端分离物在两个温度下的生长速率变异。尽管不能排除非等位基因相互作用的低发生率，但由于样本量小导致基因频率不等，可以解释与该模型的小偏差。在较正常温度下，两个分离物均检测到生长速率的定向显性，且两个分离物的显性方向相反。在生长缓慢的分离物中，显性有利于更快生长；在生长快速的分离物中，显性有利于更慢生长。如果通过稳定选择淘汰了生长速率比群体样本中恢复的更极端的分离物，那么对于一个表现出总体双向显性的性状来说，这是可以预期的。显性是温度依赖性的，在较高温度下两个分离物中均为双向显性。环境异质性、定向显性的缓冲效应以及基因型-环境相互作用，以及在生命周期的单核和双核阶段起作用的相反选择力，可能是导致这个小的局部群体中显示出相当大的自由和潜在变异性的因素。
