A MEIOTIC MUTANT AFFECTING RECOMBINATION IN FEMALE DROSOPHILA MELANOGASTER

[摘要] mei-S282 is a female meiotic mutant isolated from a natural population of Drosophila melanogaster . It is a recessive mutation located at approximately map position 5 on the third chromosome which has two major effects. It causes a nonuniform decrease in recombination which is most drastic in distal chromosome regions and nondisjunction of all chromosome pairs is elevated at the first meiotic division. Nondisjunctional events are positively correlated; furthermore, nondisjoining chromosomes, themselves nonrecombinant, are preferentially recovered from cells in which nonhomologs are preferentially recovered from cells in which nonhomologs are also non-recombinant.—It is concluded that mei-S282 is a defect which occurs early in meiosis I prior to the time of exchange. In the mutant, the frequency of no-exchange tetrads for each of the major chromosomes is increased—and in cells which contain two or more no-exchange tetrads, an interaction between these chromosomes leads to correlated nondisjunction. mei-S282 + then, is an exchange precondition necessary for the normal frequency and distribution of exchanges.

[学科分类] 医学（综合）