MEIOTIC RECOMBINATION IN YEAST - ALTERATION BY MULTIPLE HETEROZYGOSITIES
MEIOTIC RECOMBINATION IN YEAST - ALTERATION BY MULTIPLE HETEROZYGOSITIES
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DOI：
10.1126/science.2820060
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发表时间：
1987-09-18
期刊：
影响因子：
56.9
通讯作者：
HABER, JE
中科院分区：
文献类型：
--
作者：
BORTS, RH;HABER, JE
虽然减数分裂基因转换长期以来被认为伴随着交换，但对相反的情况进行直接测试是不可能的。设计了一个实验来确定在酿酒酵母中交换是否伴随着基因转换。将9个限制性位点异源性引入9-内切酶染色体间隔，其表现出22%的交换。在所有发生的交换事件中，至少59%的减数分裂交换伴随着一个或多个限制性位点异源性的基因转换。平均基因转换带长度为1.5个碱基。一个意想不到的结果是，引入少至7个杂合性显著改变了重组事件的结果，使交叉频率降低了50%，并增加了特殊四分体的数量。这种改变是由含有多个错配碱基对的异源双链DNA修复诱导的第二次重组事件引起的。
Although meiotic gene conversion has long been known to be accompained by crossing-over, a direct test of the converse has not been possible. An experiment was designed to determine whether crossing-over is accompanied by gene conversion in Saccharomyces cerevisiae. Nine restriction site heterologies were introduced into a 9-kilobase chromosomal interval that exhibits 22 percent crossing-over. Of all the exchange events that occurred, at least 59 percent of meiotic crossovers are accompanied by gene conversion of one or more of the restriction site heterologies. The average gene conversion tract length was 1.5 kilobases. An unexpected result was that the introduction of as few as seven heterozygosities significantly altered the outcome of recombination events, reducing the frequency of crossovers by 50 percent and increasing the numbers of exceptional tetrads. This alteration results from a second recombination event induced by repair of heteroduplex DNA containing multiple mismatched base pairs.