Department of Organismic and Evolutionary Biology, Center for Brain Science, Harvard University, Cambridge, MA 02138, USA.
Department of Ecology and Evolutionary Biology, Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
G3 (Bethesda). 2021 Jul 14;11(7). doi: 10.1093/g3journal/jkab129.
Drosophila melanogaster egg production, a proxy for fecundity, is an extensively studied life-history trait with a strong genetic basis. As eggs develop into larvae and adults, space and resource constraints can put pressure on the developing offspring, leading to a decrease in viability, body size, and lifespan. Our goal was to map the genetic basis of offspring number and weight under the restriction of a standard laboratory vial. We screened 143 lines from the Drosophila Genetic Reference Panel for offspring numbers and weights to create an "offspring index" that captured the number vs weight tradeoff. We found 18 genes containing 30 variants associated with variation in the offspring index. Validation of hid, Sox21b, CG8312, and mub candidate genes using gene disruption mutants demonstrated a role in adult stage viability, while mutations in Ih and Rbp increased offspring number and increased weight, respectively. The polygenic basis of offspring number and weight, with many variants of small effect, as well as the involvement of genes with varied functional roles, support the notion of Fisher's "infinitesimal model" for this life-history trait.
果蝇的产卵量（繁殖力的一个指标）是一个经过广泛研究的具有强烈遗传基础的生活史特征。随着卵发育成幼虫和成虫，空间和资源的限制会给发育中的后代带来压力，导致存活率、体型和寿命降低。我们的目标是在标准实验室小瓶的限制下，绘制后代数量和体重的遗传基础图谱。我们从果蝇遗传参考面板中筛选了 143 条品系，以测量后代数量和体重，从而创建了一个“后代指数”，该指数捕捉到了数量与重量的权衡。我们发现 18 个基因包含 30 个与后代指数变化相关的变体。使用基因敲除突变体对 hid、Sox21b、CG8312 和 mub 候选基因进行验证，表明它们在成虫阶段的存活率方面发挥了作用，而 Ih 和 Rbp 的突变分别增加了后代数量和体重。后代数量和体重的多基因基础，以及许多具有微小效应的变体，以及涉及功能作用多样化的基因，支持了这一生活史特征的 Fisher“无穷小模型”的概念。
