Stepfanie on dispersal genomics at Brazil Evolution conference: grad student Stepfanie Aguillon just presented her work on the dispersal genomics of Florida Scrub-jays at the Evolution meeting in Brazil. This project was a robust ‘rotation’ endeavor that Stepfanie motivated during this first year for her at Cornell:
Title: Genomic consequences of sex-biased dispersal in a long-lived, cooperative bird
Abstract: The movement of individuals through dispersal can strongly influence population dynamics and evolution. In particular, dispersal results in the movement of genetic material through the landscape and shapes population genetic structure as a result. The Florida Scrub-Jay (Aphelocoma coerulescens) provides an interesting opportunity to investigate the influence of dispersal on the movement of genetic material through the landscape, as they have been the focus of several, intensive long-term demographic studies. Additionally, the limited nature of dispersal in this species means that these effects may be present at a small spatial scale within a continuous population that is easily observed. Here, we use 7,389 genome-wide biallelic SNPs from all Florida Scrub-Jay nestlings at Archbold Biological Station (Florida, USA) during 2003, 2008, and 2013 to investigate the role of dispersal in shaping population genetic structure. We hypothesize that limited dispersal will result in fine-scale isolation-by-distance and differences in dispersal propensity between the sexes will result in stronger patterns in males than females. We found that females disperse significantly farther than males, which is consistent with previous work in the system. A principal component analysis showed differentiation between the northern and southern portion of the continuous study site (an area of ~10 km in length) in the autosomal, but not the sex-linked, SNPs. There is a significant pattern of isolation-by-distance in both sexes, such that nestlings are more related to individuals nearby than individuals that are farther away. Contrary to our expectations, the strength of the relationship did not differ between the sexes, but was variable across years. Thus, the unique life history of the Florida Scrub-Jay has resulted in isolation-by-distance at a small spatial scale within a continuous population, an unusual phenomenon not previously observed in birds.