Geneticists have tackled a question that has perplexed humanity since the dawn of time: does love at first sight truly exist?

Maybe, according to a study published in the April 2009 issue of the journal GENETICS.  A team of scientists from the United States and Australia say they have discovered that, at the genetic level, some males and females are more compatible than others, and that this compatibility plays an important role in mate selection, mating outcomes, and future reproductive behaviors. In experiments involving fruit flies, the researchers found that before mating, females experience what amounts to "genetic priming," making them more likely to mate with certain males over others.

To reach their conclusions, scientists mated two different strains of fruit fly females to males either from their own strain or to males from the other strain. They noted the males with which females of each strain tended to mate and then examined whether the females showed differences in behavior soon after mating and in reproduction-related activities, such as how many offspring were produced and how many sperm were stored.

They also examined the females' RNA to compare the genes expressed in females mated to males of different strains. They found that despite observed differences in mating behaviors and reproduction activities in females mated to different strains of males, there were only negligible mating-dependent differences in gene expression between the groups.

This suggests that genetic changes involved in mate choice and reproduction were in place before mating began.

"Our research helps to shed light on the complex biochemistry involved in mate selection and reproduction," said Mariana Wolfner, Professor of Developmental Biology at Cornell University and the senior scientist involved in the study. "These findings may lead to ways to curb unwanted insect populations by activating or deactivating genes that play a role in female mating decisions," she added.

"It appears that females really do care about the character of their consorts," said Mark Johnston, Editor-in-Chief of the journal GENETICS, "but they may not have as much control over our choice of mates as they'd like to think."

Article: Lisa A. McGraw, Greg Gibson, Andrew G. Clark and Mariana F. Wolfner, 'Strain-Dependent Differences in Several Reproductive Traits Are Not Accompanied by Early Postmating Transcriptome Changes in Female Drosophila melanogaster',Genetics.2009; 181: 1273-1280 doi:10.1534/genetics.108.099622