Odours play a vital role in mate selection

Washington, Dec 9 : Odours play an important role in mate selection, says a study.

Humans have the same receptors for detecting odours bearing on sex as do other apes and primates. But each species uses them in different ways, stemming from the way the genes for these receptors have evolved over time, according to researchers from Duke University Medical Centre (DUMC).

Varying sensitivity to these sex-steroid odours may play a role in mate selection -- and perhaps prevent cross-species couplings, the researchers speculate.

The researchers analysed the sequences and functions of the gene for the odorant receptor OR7D4 in terms of perceiving two steroid molecules related to testosterone, androstenone and androstadienone.

The study did not try to examine how the receptors and odour perception might relate to behaviour.

"There's variation in sensitivity of the odorant receptor from this gene (all primates) have," said Hiroaki Matsunami, associate professor of molecular genetics and microbiology and neurobiology at DUMC.

"Maybe these molecules operate in the process of reproduction. The fact that there is variation fits with this theory. Reproduction demands that an animal avoid attraction to other species, so variation in the receptor's sensitivity to these odours may prevent any cross-species attraction."

Animals rely on olfactory signals to make all sorts of decisions about other animals, particularly in reproduction, said Christine Drea, associate professor of biology at DUMC.

"Beyond identifying members of the same species, odours help identify kin or non-kin, members of the opposite sex, even whether individuals are fertile or genetically appropriate as mates. How they do so is still largely unknown," she said.

"By deciphering evolutionary changes in receptor function across species, Matsunami and his colleagues have brought us another step closer to unravelling the mysteries of olfactory signalling," said Drea.

The study was published online in Proceedings of the National Academy of Sciences.