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Schlagwörter:
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Zusammenfassung:
To understand how variation in sexual communication systems
evolves, the genetic architecture underlying sexual signals and
responses needs to be identified. Especially in animals where
mating signals are important for mate recognition, and signals
and responses are governed by independently assorting genes,
it is difficult to envision how signals and preferences can
(co)evolve. Moths are a prime example of such animals. In the
noctuid moth Heliothis virescens, we found within-population
variation in the female pheromone. In previous selection
experiments followed by quantitative trait locus (QTL) analysis
and expression analysis of candidate desaturase genes, we
developed a model involving a trans-acting repressor of the
delta-11-desaturase. In our current study with new selection
lines, we fixed the most extreme phenotype and found a single
underlying mutation: a premature stop codon in the first
coding exon of delta-11-desaturase, which we could trace back
to its origin in the laboratory. Interestingly, we found no
pleiotropic effects of this knock-out mutation on the male
physiological or behavioural response, or on growth or fertility.
This finding is in contrast to Drosophila melanogaster, where a
single desaturase gene affects both female pheromone
production and male behavioural response, but similar to other
Lepidoptera where these traits are under independent genetic
control. To our knowledge, this is the first time that a single
point mutation has been identified that underlies the phenotypic variation in the pheromone signal of a moth.
