Genetics of Natural Populations. V. Relations between Mutation Rate and Accumulation of Lethals in Populations of Drosophila Pseudoobscura.
Genetics of Natural Populations. V. Relations between Mutation Rate and Accumulation of Lethals in Populations of Drosophila Pseudoobscura.
复制标题
自然种群遗传学。
作者：
Theodosius Dobzhansky;Sewall Wright
伪果蝇的自然种群在杂合条件下携带大量隐性突变基因（STURTEVANT 1937， DOBZHANSKY和QUEAL 193813， DOBZHANSKY 1939）。这些基因中有些是致命的或半致命的，有些产生明显的外部影响，还有一些改变生存能力、发育持续时间或其他特征。尽管在上述基因变异中，致命的似乎是最不可能在进化中发挥建设性作用的，但它们是种群研究的有利材料。它们的检测不涉及个人方程式，在技术上比肉眼或生理过程的修饰物的检测更简单。而且，致命的，只要是完全隐性的，只有在纯合子条件下，当其适应值为零时，才会受到自然选择的影响；通过实验确定其他基因的适应值是一项最难以捉摸的任务。本文报告了在自然种群中发现的由等位基因所显示的致命性同一性的研究结果；通过选择消除致命物种的比率；以及它们通过突变重新产生的比率。数学分析仅限于对致死事件发生数据的影响。关于伪果蝇种群结构的其他信息来源的考虑，如染色体结构的可变性，保留给未来的出版物。本论文所依据的观察和实验工作是在帕萨迪纳加州理工学院生物系的支持下进行的，并得到了纽约卡内基公司通过华盛顿卡内基研究所提供的资助，感谢他们的帮助。M. L. QUEAL小姐、B. A. SPASSKY先生和N. P. SIVERTZEV-DOBZHANSKY夫人分享了所涉及的技术工作。DRS。MORGAN WARD， K. MATHER和H. J. MULLER提出了关于计算可变位点最小数量的替代方法的建议。
ATURAL populations of Drosophila pseudoobscura have been shown N to carry numerous recessive mutant genes concealed in heterozygous condition (STURTEVANT 1937, DOBZHANSKY and QUEAL 193813, DOBZHANSKY 1939). Some of these genes are lethal or semilethal, others produce visible external effects, and still others modify the viability, duration of the development, or other characters. Although the lethals would seem to be least likely among the above genetic variants to play a constructive role in evolution, they are favorable material for population studies. Their detection involves no personal equation and is technically simpler than that of the visibles or of modifiers of physiological processes. Moreover, a lethal, provided it is completely recessive, is subject to natural selection only in homozygous condition, when its adaptive value is zero ; experimental determination of the adaptive values of other genes is a most elusive task. The present article reports the results of a study of the identity of lethals found in natural populations as shown by their allelism; of the rate of elimination of lethals by selection; and of the rate of their de novo origin by mutation. The mathematical analysis is restricted to the implications from the data on the occurrence of lethals. The consideration of other sources of information regarding the population structure in Drosophila pseudoobscura, such as the variability of the chromosome structure, is reserved for a future publication. The observational and experimental work on which the present paper is based was carried through a t the Division of Biology of the California Institute of Technology, Pasadena, with the support of a grant from the Carnegie Corporation of New York, made through the Carnegie Institution of Washington, whose help is gratefully acknowledged. MISS M. L. QUEAL, MR. B. A. SPASSKY, and MRS. N. P. SIVERTZEV-DOBZHANSKY have shared the technical work involved. DRS. MORGAN WARD, K. MATHER, and H. J. MULLER have contributed advice concerning alternative methods of calculation of the minimum number of mutable loci.