遗传背景改变了纤毛虫嗜热四膜虫中 mat 等位基因之间的优势关系。

Genetic background alters dominance relationships between mat alleles in the ciliate Tetrahymena thermophila.

机构信息

the Department of Biology and Biochemistry, University of Houston, Houston, TX 77204. Sujal S. Phadke is now at the Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109. Tiago Paixão is now at the Institute of Science and Technology Austria.

出版信息

J Hered. 2014 Jan-Feb;105(1):130-5. doi: 10.1093/jhered/est063. Epub 2013 Nov 4.

DOI:10.1093/jhered/est063

PMID:24190504

Abstract

The pattern of inheritance and mechanism of sex determination can have important evolutionary consequences. We studied probabilistic sex determination in the ciliate Tetrahymena thermophila, which was previously shown to cause evolution of skewed sex ratios. We find that the genetic background alters the sex determination patterns of mat alleles in heterozygotes and that allelic interaction can differentially influence the expression probability of the 7 sexes. We quantify the dominance relationships between several mat alleles and find that A-type alleles, which specify sex I, are indeed recessive to B-type alleles, which are unable to specify that sex. Our results provide additional support for the presence of modifier loci and raise implications for the dynamics of sex ratios in populations of T. thermophila.

摘要

遗传模式和性别决定机制可能具有重要的进化后果。我们研究了纤毛虫嗜热四膜虫中的概率性别决定，先前的研究表明这种性别决定会导致偏性性别比的进化。我们发现遗传背景会改变杂合子中 mat 等位基因的性别决定模式，并且等位基因相互作用可以不同地影响 7 种性别表达的概率。我们量化了几个 mat 等位基因之间的显性关系，发现指定性别 I 的 A 型等位基因确实对无法指定该性别的 B 型等位基因是隐性的。我们的结果为修饰基因座的存在提供了额外的支持，并对嗜热四膜虫种群中性别比例的动态变化提出了影响。