When housekeeping behavior is under genetic control

Those who have already used the excuse that “housekeeping is not in my DNA” to try to avoid this chore may not have been entirely wrong. Indeed, at least in honey bees, certain shortcomings in hive hygiene appear to be linked to the overexpression of genes that impairs the detection of odors released by diseased or dead larvae.

This is at least what a study recently published in BMC Genomics suggests. The study was conducted by Sébastien Boutin, Pierre-Luc Mercier, Pierre Giovenazzo, and Nicolas Derome from the Department of Biology and the Institute of Integrative and Systems Biology, together with Mohamed Alburaki from the University of Tennessee.

First described in honey bees in 1937, hygienic behavior consists of detecting diseased or dead larvae and removing them from the hive. This collective defense mechanism, which protects the colony against infections and parasites, appears to be linked to the olfactory abilities of nurse bees—the young workers that care for the brood. Hygienic behavior is thought to be under genetic control, but studies on the subject differ in their conclusions regarding the number of genes involved.

To shed new light on this issue, researchers at Université Laval compared gene expression in the brains of bees from colonies exhibiting strong hygienic behavior—more than 90% of dead larvae removed within 24 hours—with that of bees from non-hygienic colonies, in which fewer than 50% of dead larvae were removed over the same period.

The researchers measured RNA expression in the brains of 75 bees from three hygienic colonies and 125 bees from five non-hygienic colonies. Of the approximately 10,000 expressed genes, only 96 showed significantly different expression levels between the two groups.

Interestingly, six of the genes overexpressed in non-hygienic bees were directly or indirectly related to cytochrome P450 proteins, which are involved in the degradation of pollutants, insecticides, or hormones. “These enzymes are also likely associated with the breakdown of odorant compounds,” notes Nicolas Derome. “Non-hygienic bees that overexpress P450 would degrade more of the chemical compounds released by diseased or dead larvae, thereby reducing their ability to detect and remove them.”

This research provides new insight into the genetic basis of hygienic behavior, but it also has practical implications. The genes that distinguish the two groups represent potential targets for selective breeding programs aimed at producing highly hygienic bee lineages that are better equipped to defend themselves against parasites and infections.

Source: http://www.techno-science.net/?onglet=news&news=14412