Latitudinal and cold-tolerance variation associate with DNA repeat-number variation in the hsr-omega RNA gene of Drosophila melanogaster

Abstract

An 8-bp deletion in the hsr-omega heat-stress gene of Drosophila melanogaster has previously been associated with latitude, and with heat tolerance that decreases with latitude. Here we report a second polymorphic site, at the 3′-end of hsr-omega, at which multiple alleles segregate in natural populations for copy number of a ∼280 bp tandem repeat. On each of 3 consecutive years (2000, 2001 and 2002) among populations sampled along the Australian eastern coast, repeat number was negatively associated with latitude. Neither altitudinal association was detected in 2002 when five high-altitude sites were included, nor was a robust association detected with local temperature or rainfall measures..