Cytogenetics of genomic exclusion in Tetrahymena.
Cytogenetics of genomic exclusion in Tetrahymena.
复制标题
四膜虫基因组排除的细胞遗传学。
作者：
S. Allen
在梨形四膜虫（Tetrahymena pyriformis）的同原1中观察到的一种不正常的接合形式。在一个菌株的某些克隆与其他菌株的正常克隆的杂交中，只有来自正常亲本的基因出现在后代中，尽管两个接合体都被恢复，并且都是二倍体和表型相同。对基因组排斥的核基础的部分了解来自于C*的杂交结果，C*是近交系C株的异常克隆，而AB株的正常克隆是H血清型等位基因的杂合，与C株中发现的等位基因不同（ALLEN 1963）。在后代中只回收到来自AB菌株的等位基因，并且后代以大约1:2:1的比例分布在三个表型类中。这一观察结果表明，来自AB亲本的两个减数分裂产物联合形成合核。
ENOMIC exclusion is an abnormal form of conjugation that has been observed in syngen 1 of Tetrahymena pyriformis In crosses of certain clones of a strain to normal clones of other strains, only the genes derived from the normal parent appeared in the progeny, although both exconjugants were recovered, and both were diploid and identical in phenotype. Partial insight into the nuclear basis of genomic exclusion came from the results of a cross of C*, an abnormal clone of the inbred C strain, and a normal clone from the AB strain, heterozygous for H serotype alleles distinct from those found in strain C (ALLEN 1963). Only alleles derived from strain AB were recovered in the progeny, and the progeny were distributed among three phenotypic classes in an approximate 1:2:1 ratio. This observation suggested that two meiotic products from the AB parent united to form the syncaryon.