对具有异常高核糖体DNA含量的单倍体酵母菌株的研究。III. γ-DNA片段的不均等减数分裂分离

Study of a haploid yeast strain with an unusually high rDNA content. III. Unequal meiotic segregation of the gamma-DNA fraction.

作者信息

Oyen T B, Saelid G, Skuladottir G V

出版信息

Biochim Biophys Acta. 1978 Aug 23;520(1):88-102. doi: 10.1016/0005-2787(78)90010-2.

Abstract

DNA from different strains of Saccharomyces cerevisiae has been fractionated in preparative Ag+/Cs2-SO4 density gradients. The results show that there are real differences in amount of the nuclear satellite component, the gamma-DNA, from one strain to the other. The gamma-DNA forms a homogeneous dense band that contains all the rDNA, and the amount of gamma-DNA estimated from the gradients can be correlated to amount of rDNA derived from rRNA-DNA hybridizations. By various crossings and sporulations we have obtained diploid and haploid strains with gamma-DNA contents ranging from 7 to 20% of the nuclear DNA. During meiosis, the amount of gamma-DNA appears to segregate in a pattern that indicates unequal crossing over as a possible mechanism for differences in gamma-DNA contents.

摘要

来自不同酿酒酵母菌株的DNA已在制备性Ag⁺/Cs₂SO₄密度梯度中进行了分级分离。结果表明，不同菌株间核卫星成分（γ-DNA）的含量存在实际差异。γ-DNA形成一条均一的致密带，其中包含所有的rDNA，从梯度中估算出的γ-DNA含量可与通过rRNA-DNA杂交得到的rDNA含量相关联。通过各种杂交和孢子形成，我们获得了γ-DNA含量占核DNA 7%至20%的二倍体和单倍体菌株。在减数分裂过程中，γ-DNA的含量似乎以一种模式分离，这表明不等交换可能是γ-DNA含量差异的一种机制。