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RELEASE OF GENETIC VARIABILITY THROUGH RECOMBINATION. II. DROSOPHILA PERSIMILIS

1959; Oxford University Press; Volume: 44; Issue: 1 Linguagem: Inglês

10.1093/genetics/44.1.43

1943-2631

Eliot B. Spiess,

Insect and Pesticide Research

Two samples of ten second chromosomes each of Drosophila persimilis were chosen for their near normal viability in homozygous condition from populations occupying localities in Yosemite National Park, California. A total of 1900 recombinant chromosomes from these original 20 were tested for viability effects in homozygous condition. Recombinant viabilities are lower on the average than control viabilities, that is they regress toward the average viability of homozygotes in the populations from which they come. The range of viability observed among recombinants extended from lethality to supervitality, but neither the number nor distribution of lethals is greater than or unaccountable by point mutation. This fact is in marked contrast with D. pseudoobscura which certainly produced some lethals synthetically, that is by recombination. Analysis of variance shows a significant increase in the genetic components of variability especially in interaction effects on viability and variance differences over their controls. None the less, the magnitude of this array of variance is not as great as in the sibling species, pseudoobscura. While it is known that both species are highly heterozygous, it is possible that the difference between them in these recombinant effects may be due to less epistatic interaction of nonallelic loci in persimilismore » than in pseudoobscura. On the other hand a real difference in amount of heterozygosity between these species may account for their differences in recombination effects. (auth)« less