BRC-BIO: Detection of Nicrophorus orbicollis indirect genetic effects critical for fitness

Anecdotally, most people can point to how a parent, sibling, relative, or friend has influenced the person they have become. In many non-human species, of course, the influence of relatives or other social partners on an individual’s characteristics can also be important, and if those influences are genetic, they can play a major role in determining the evolutionary fates of those species.

However, little is known about the specific genetic mechanisms by which social partners can affect each other. Among organisms where social influences are known to be critical are burying beetles, which provide advanced parental care to their offspring through the regurgitation of partially digested carrion. This project will use whole genome sequencing to identify the genes in mothers that cause variation in a set of offspring traits that may be linked to fitness.

The project will train one graduate student and numerous undergraduates in modern molecular, bioinformatic, and statistical techniques, and will generate computational resources for the classroom previously unavailable to students at Austin Peay State University. In addition, outside speakers will be brought in to discuss how techniques like those used in this project have the potential to affect everyday life through advances in medicine, agriculture, and social science, giving students the chance to connect what goes on in the lab to the broader world.

Social influences, known as indirect genetic effects (IGE), are theorized to play especially important roles in phenotypic evolution. However, the empirical study of IGEs has been hampered by a lack of ability to find the specific alleles that generate them. Finding these alleles can answer three major questions.

First, is the architecture of IGEs largely polygenic, or do any major effect alleles play a role? Second, what genes are found to confer IGEs, and can any generalizable conclusions about molecular mechanisms come from identifying these genes and the pathways in which they operate? And third, what is the molecular nature of genetic correlations between IGEs and more standard individual contributions of genotype to phenotpe (direct genetic effects; DGE)?

This project will generate 1500 families of the burying beetle Nicrophorus orbicollis using cross-fostering, so that mothers rear unrelated offspring. Each mother will be genotyped via low-coverage genome sequencing, and a genome-wide association study (GWAS) will be used to predict offspring phenotypes using maternal genotypes. Three offspring from each family will also be sequenced so that DGEs can be estimated alongside IGEs, allowing for estimation of genetic correlations between them.

In addition to addressing the questions raised above, the project will will enable functional genomic studies using CRISPR/Cas9 and will generate new hypotheses for population genetic studies of allele frequency change over space and time.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.