GENE CONVERSION AND INTRAGENIC RECOMBINATION AT SUP6 LOCUS AND SURROUNDING REGION IN SACCHAROMYCES-CEREVISIAE

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  • 1 January 1976
    • journal article
    • research article
    • Vol. 84  (4) , 697-721
Abstract
Spontaneous secondary mutations of the ochre suppressor SUP6 were selected in a haploid strain of S. cerevisiae. Unselected tetrads were dissected from crosses heterozygous for 1 of 3 alleles of SUP6 and for 3 other loci in this region which span a length of 14 map units his2, cdc14 and met10. All of these markers were characterized by high frequency of meiotic gene conversion and long conversion lengths which frequently extended into adjacent marked loci. Despite the high conversion frequency of SUP6, recombination between alleles of this locus reached a maximum frequency of only 2 .times. 10-3 prototrophs/spore. Although the allelic recombination frequencies were not distance dependent and so could not be used to order the alleles, the inequality between the 2 recombinant outside marker combinations among selected intragenic recombinants produced an internally consistent map of the suppressor locus. Recombination at SUP6, whether detected as conversion in tetrads or as the production of recombinants among random spores, was accompanied by significantly less than 50% outside marker recombination.