Affiliation: University of California - Berkeley, Berkeley, California
Keywords: a. genome evolution; j. fat body
Horizontal Gene Transfer (HGT) is the movement of genetic material between species, as opposed to via transmission from parent to offspring (i.e. vertical gene transfer). A growing body of evidence underscores the role of HGT in animal evolution. We previously discovered HGT of an apoptosis-inducing gene, aip56, into the nuclear genomes of the tephritid fruit fly genus Bactrocera, a genus that includes destructive fruit pests. In this study, we characterize the timing and evolution of aip56 HGT in the Bactrocera lineage. We use PCR, Sanger sequencing, and analysis of publicly accessible genome assemblies to determine that aip56 was transferred into the nuclear genome of a Bactrocera ancestor ca. 63 mya, and is highly expressed in the fat body. Additionally, we analyze the structure of AIP56 in Bactrocera using Phyre2 and find that the C-terminus has a high-confidence match to a rhamnose-binding domain, which suggests an immune function. Our results suggest that HGT of aip56 served an adaptive function that may have facilitated the success of this agriculturally devastating clade.