PgmNr P374: An Ion-channel Gene Causes Natural Courtship Song Variation in Drosophila.

Authors:
Yun Ding 1 ; Augusto Berrocal 1,2 ; Tomoko Morita 1 ; Kit Longden 1 ; David Stern 1


Institutes
1) Janelia Research Campus, HHMI, Ashburn, VA; 2) UC Berkeley, Berkeley, CA.


Abstract:

Animal species display enormous variation for innate behaviors, but little is known about how genomes evolve to generate this diversity. The features of Drosophila courtship song are easy to quantify and vary widely within and between species, making song an excellent system for genetic studies. We developed a mapping strategy that combined traditional mapping protocol with high-resolution recombinant mapping using engineered visible markers via CRISPR/Cas9 genome editing. This approach allowed us to map the sine song frequency difference between two wild isolates, Drosophila simulans 5 and D. mauritiana 29, to a 966 bp region within the slowpoke locus, which encodes a calcium-activated potassium channel. We confirmed that slowpoke is the causal locus using a reciprocal hemizygosity test, and further narrowed down the casual mutation to an intronic insertion of retrotransposon that occurred within D. simulans populations. Difference in exon usage was observed around the retrotranspon insertion site. Like many ion-channel genes, slowpoke is expressed widely in the nervous system and influences many behaviors. The slowpoke mutants sing very little song with disrupted features. However, the naturally evolved slowpoke alleles cause significant variation in only one component of courtship song, showing that a highly pleiotropic ion channel gene can evolve to generate a specific new behavior pattern through changes in gene regulation. Currently, we are trying to confirm the retrotranspon insertion as the causal mutation by targeted deletion, and identify the molecular mechanism of how the retrotranspon insertion has fine-tuned the slowpoke function. .