Genomic signatures of local adaptation in the Drosophila immune response.

Fly (Austin)
Authors
Keywords
Abstract

As environments and pathogen landscapes shift, host defenses must evolve to remain effective. Due to this selection pressure, among-species comparisons of genetic sequence data often find immune genes to be among the fastest evolving genes across the genome. The full extent and nature of these immune adaptations, however, remain largely unexplored. In a recent study, we analyzed patterns of selection within distinct components of the Drosophila melanogaster immune pathway. While we found evidence of positive selection within some immune processes, immune genes were not universally characterized by signatures of strong selection. On the contrary, we even found that some immune functions show greater than expected constraint. Overall these results highlight 2 major factors that appear to play an outsize role in determining a gene's evolutionary rate: the type of pathogen the gene targets and the gene's position within the immune network. These results join a growing body of literature that highlight the complexity of immune adaptation. Rather than there being uniformly strong selection across all immune genes, a combination of pathogen-specificity and host genetic constraints appear to play key roles in determining each immune gene's individual evolutionary trajectory.

Year of Publication
2017
Journal
Fly (Austin)
Volume
11
Issue
4
Pages
277-283
Date Published
2017 10 02
ISSN
1933-6942
DOI
10.1080/19336934.2017.1337612
PubMed ID
28586288
PubMed Central ID
PMC5721942
Links
Grant list
R01 AI064950 / AI / NIAID NIH HHS / United States