Data from: One QTL for intra- and interspecific variation in a sex pheromone

Even though premating isolation is hypothesized to be a major driving
force in speciation, its genetic basis is poorly known. In the noctuid
moth Heliothis subflexa, one group of sex pheromone components, the
acetates, emitted by the female, plays a crucial isolating role in
preventing interspecific matings to males of the closely related Heliothis
virescens, in which females do not produce acetates and males are repelled
by them. We previously found intraspecific variation in acetates in H.
subflexa: females in eastern North America contain significantly more
acetates than females in Western Mexico. Here we describe the persistence
of this intraspecific variation in laboratory-reared strains and the
identification of one major quantitative trait locus (QTL), explaining 40%
of the variance in acetate amounts. We homologized this intraspecific QTL
to our previously identified interspecific QTL using
restriction-associated DNA (RAD) tags. We found that a major intraspecific
QTL overlaps with one of the two major interspecific QTL. To identify
candidate genes underlying the acetate variation, we investigated a number
of gene families with known or suspected acetyl- or acyltransferase
activity. The most likely candidate genes did not map to our QTL, so that
we currently hypothesize that a transcription factor underlies this QTL.
Finding a single, large QTL that impacts variation in pheromone blends
between and within species is, to our knowledge, the first such example
for traits that have been demonstrated to affect premating isolation.