Extensive heterosis in growth of yeast hybrids is explained by a combination of
genetic models |
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Authors: | R Shapira T Levy S Shaked E Fridman L David |
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Institution: | 1.Department of Animal Sciences, RH Smith
Faculty of Agriculture, Food and Environment, The Hebrew University of
Jerusalem, Rehovot, Israel;2.The RH Smith Institute for Plant Sciences
and Genetics, RH Smith Faculty of Agriculture, Food and Environment, The Hebrew
University of Jerusalem, Rehovot, Israel |
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Abstract: | Heterosis, also known as hybrid vigor, is the superior performance of a heterozygous
hybrid relative to its homozygous parents. Despite the scientific curiosity of this
phenotypic phenomenon and its significance for food production in agriculture, its
genetic basis is insufficiently understood. Studying heterosis in yeast can
potentially yield insights into its genetic basis, can allow one to test the
different hypotheses that have been proposed to explain the phenomenon and allows
better understanding of how to take advantage of this phenomenon to enhance food
production. We therefore crossed 16 parental yeast strains to form 120 yeast hybrids,
and measured their growth rates under five environmental conditions. A considerable
amount of dominant genetic variation was found in growth performance, and heterosis
was measured in 35% of the hybrid–condition combinations. Despite
previous reports of correlations between heterosis and measures of sequence
divergence between parents, we detected no such relationship. We used several
analyses to examine which genetic model might explain heterosis. We found that
dominance complementation of recessive alleles, overdominant interactions within loci
and epistatic interactions among loci each contribute to heterosis. We concluded that
in yeast heterosis is a complex phenotype created by the combined contribution of
different genetic interactions. |
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