Laboratory of Evolutionary Ecology, Graduate School of Environmental Science, Okayama University, Okayama, Japan.
Heredity (Edinb). 2010 Sep;105(3):268-73. doi: 10.1038/hdy.2010.4. Epub 2010 Feb 10.
Circadian rhythms are ubiquitous in a wide variety of organisms, although their genetic variation has been analyzed in only a few species. We found genetic differences in the circadian rhythm of adult locomotor activity among strains of the adzuki bean beetle, Callosobruchus chinensis, which differed in origin and have been maintained in isolation. All beetles in some strains clearly had free-running rhythms in constant darkness whereas most beetles in other strains were arrhythmic. The period of free-running rhythm varied from approximately 19 to 23 h between the strains. F(1) males from reciprocal crosses among strains with different periods of circadian rhythms had circadian periods that were intermediate between their parental strains. Segregation of the circadian rhythm appeared in the F(2) generation. These findings are consistent with the hypothesis that variation in the period length of circadian rhythm is explained by a major autosomal gene with additive effects and no dominance. This hypothesis was supported by the joint scaling test for the free-running period in the F(1) and F(2) generations. We discuss possible causes for genetic variation in circadian rhythm in the C. chinensis strains in terms of random factors and selection.
昼夜节律在广泛的生物体中普遍存在，尽管其遗传变异仅在少数物种中进行了分析。我们发现，在起源不同且已被隔离的赤豆象 Callosobruchus chinensis 菌株中，成年运动活性的昼夜节律存在遗传差异。一些菌株中的所有甲虫在持续黑暗中都明显具有自由运行的节律，而其他菌株中的大多数甲虫则没有节律。自由运行节律的周期在不同菌株之间大约在 19 到 23 小时之间变化。来自具有不同昼夜节律周期的菌株之间的回交 F1 雄性具有介于其亲本菌株之间的昼夜周期。昼夜节律的分离出现在 F2 代中。这些发现与假设一致，即昼夜节律周期长度的变化是由具有加性效应且无显性的主要常染色体基因解释的。该假设得到了 F1 和 F2 代自由运行周期的联合缩放检验的支持。我们根据随机因素和选择讨论了 C. chinensis 菌株昼夜节律遗传变异的可能原因。
