Data from: Extensive heterosis in growth of yeast hybrids is explained by a combination of genetic models

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.

杂种优势（heterosis），又称杂交活力（hybrid vigor），是指杂合杂种相较于其纯合亲本所展现出的优良性状。尽管这一表型现象兼具科学研究价值与农业粮食生产的重要意义，但其遗传基础仍未得到充分阐明。在酵母中开展杂种优势研究，既有助于深入解析其遗传机制，亦可用于检验已提出的各类解释该现象的假说，还能帮助我们更好地理解如何利用该现象提升粮食产量。为此，我们将16株亲本酵母菌株进行杂交，构建得到120株酵母杂种，并在五种环境条件下测定了它们的生长速率。研究发现，生长性能存在大量显性遗传变异，且在35%的杂种-环境组合中检测到了杂种优势。尽管此前有研究报道杂种优势与亲本间序列分化程度存在相关性，但我们并未发现此类关联。我们通过多种分析方法探究了能够解释杂种优势的遗传模型，结果发现隐性等位基因的显性互补、基因座内的超显性互作以及基因座间的上位性互作，均对杂种优势具有贡献。综上，在酵母中，杂种优势是一种由多种遗传交互作用共同塑造的复杂表型性状。