Genetic basis of variation in immune function  in Drosophila melanogaster selected for fast development and late reproduction

Abstract

Genes with immune functions are rapidly evolving genes. Understanding the genetic architecture that facilitates this change is a challenge for evolutionary biologists. Previously, we have reported heightened immune surveillance in Drosophila selected for faster development and longer life span. In this work we tested whether genome architecture of innate immunity evolves as a consequence of long-term selection for life history traits (faster development and longer lifespan) by checking the single nucleotide polymorphism changes accumulated in genes involved in immune system and hematopoiesis. We found 2 important genes with high impact SNPs in immune related genes namely, Nim B5 and Tep 3 (Thioester-containing protein 3), of which Tep3 gene was found to be transcriptionally upregulated among selected populations. Tep3 has been known to have endopeptidase inhibitor activity. It is involved in the biological process of phagocytosis, defense response to other organism, and defense response to Gram-positive bacterium. Further NimB5 is involved in regulating hematopoiesis. Here we propose that TEP3 and NimB5 might be working collectively in evolving flies with better adaptability by modulating their immune system.