View Program - 63rd Annual Drosophila Research Conference

A century of genetic research has revealed that there are numerous causes of organismal trait variation. These include important contributions from an organism's genotype, environment, age, and even the environment experienced by previous generations referred to as transgenerational effects. While a multitude of studies has demonstrated diverse and abundant effects of each source of variation in a wide variety of organisms, the relative contribution of the different sources of variation remains largely unknown. This has largely resulted from a lack of studies that simultaneously determine the contributions of each source of variation within a single experiment, and this is especially true for transgenerational effects that are in general poorly understood. Here we quantified genome-wide gene expression traits in Drosophila and compared the contribution of genotype (D. simulans vs. D. sechellia), environment (control food vs octanoic acid food), age/developmental stage (L3 larvae vs adult), and previous generation environment (control food vs octanoic acid food) to variation in gene expression levels. We followed this with analysis of genome-wide allele-specific expression in F1 hybrids between D. simulans and D. sechellia to disentangle the cis and trans-regulatory contributions to differences in variation for each source of variation. We found that genotype and developmental stage have much greater effects on gene expression than environmental differences and all were much more abundant than the variation due to trans-generational effects from previous generation exposure to different environments. By simultaneously analyzing major sources of variation in the same experiment, our results suggest a hierarchy of importance of the different sources of variation in traits that answers a long-standing question in genetics.

Sources of variation in gene expression