Data from: The decline in fitness with inbreeding: evidence for negative dominance-by-dominance epistasis in Drosophila melanogaster

Genetic interactions can play an important role in the evolution of
reproductive strategies. In particular, negative dominance-by-dominance
epistasis for fitness can theoretically favour sex and recombination. This
form of epistasis can be detected statistically because it generates
nonlinearity in the relationship between fitness and inbreeding
coefficient. Measures of fitness in progressively inbred lines tend to
show limited evidence for epistasis. However, tests of this kind can be
biased against detecting an accelerating decline due to line losses at
higher inbreeding levels. We tested for dominance-by-dominance epistasis
in Drosophila melanogaster by examining viability at five inbreeding
levels that were generated simultaneously, avoiding the bias against
detecting nonlinearity that has affected previous studies. We find an
accelerating rate of fitness decline with inbreeding, indicating that
dominance-by-dominance epistasis is negative on average, which should
favour sex and recombination.

遗传互作在繁殖策略的演化中可发挥重要作用。具体而言，针对适合度（fitness）的负显性×显性上位性（dominance-by-dominance epistasis），理论上可对有性生殖与重组产生促进效应。该类型的上位性（epistasis）可通过统计学方法检出，因其会在适合度与近交系数（inbreeding coefficient）的相关性中引入非线性特征。对逐步近交系的适合度测定结果，往往仅能提供有限的上位性检测证据。然而，此类检测方法可能因较高近交水平下的品系丢失，而对检测适合度的加速下降存在偏倚。本研究以黑腹果蝇（Drosophila melanogaster）为实验材料，通过同步构建5个近交水平的品系并检测其生活力（viability），规避了此前研究中影响非线性特征检测的偏倚问题。研究结果显示，随着近交程度提升，适合度下降速率呈加速趋势，表明平均而言显性×显性上位性为负，这一结果应可促进有性生殖与重组的演化。