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You are here: News & Events On the Research Front On The Research Front Multiple Mating Queen Bees Help Maintain Genetic Diversity in Apis dorsata

Multiple Mating Queen Bees Help Maintain Genetic Diversity in Apis dorsata

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Chennai, April 17, 2012: Mattila and other researchers have recently shown that colonies with genetically diverse populations of workers, a result of the highly promiscuous mating behavior of queens, are healthier than colonies with genetically uniform worker bee populations (see news dated March 14, 2012 in this site). A latest study* on the giant honey bee (Apis dorsata) colonies in China published on April 12, 2012 in the journal PLoS ONE demonstrates a similar trend in this bee species.

In its detailed analysis of the sex determining  alleles in the giant honey bee populations in China, a team of researchers led by Zachary Huang, Michigan State University, USA tested whether A. dorsata populations on Hainan Island, which is separated geographically from the mainland China by over 18 - 33 km and isolated geologically for more than 20 million years, experience the founder effect (loss  of genetic variation due to a limited number of genes in the initial gene pool in the population, and subsequent inbreeding) and stronger positive selection "by comparing csd (complementary sex determiner) genes in workers sampled on the island and those on the mainland." Based on the results of their study, the researchers suggest "that due to the highly polyandrous nature of honey bees, the founder effect does not apply to the csd gene in Apis dorsata, perhaps also to any other gene, to most Apis species." Following is the news story dated April 16, 2012  issued with regard to this study by the Michigan State University.

*Reference cited: Liu, Z.Y., Wang, Z.L., Yan, W.Y., Wu, X.B., Zeng, Z.J. and Huang, Z.Y. 2012. The sex determination gene shows no Founder effect on the giant honey bee, Apis dorsata. PLoS ONE 7 (4): e34436. doi:10.1371/journal.pone.0034436

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Promiscuous queen bees maintain genetic diversity

Contact: Layne Cameron, Office of Communications, Office: (517) 353-8819, Cell: (765) 748-4827, This e-mail address is being protected from spambots. You need JavaScript enabled to view it ; Zachary Huang, Entomology, This e-mail address is being protected from spambots. You need JavaScript enabled to view it

Published: April 16, 2012

East Lansing, Mich. -- By mating with nearly 100 males, queen bees on isolated islands avoid inbreeding and keep colonies healthy.

The results, published in the current issue of PLoS ONE, focused on giant honey bee colonies on Hainan Island, off the coast of China. Since these bees have long been separated from their continental cousins, it was thought that the island bees would  be prime candidates for inbreeding as well as having very different genes, said Zachary Huang, Michigan State University entomologist.

"We believed that the island bees would show evidence of the founder effect, or random genetic changes in an isolated population, on a unique sex determination gene from the mainland bees," he said. "At first we were surprised when we couldn't document this effect. Looking at it further, I asked myself, 'Why didn't I think of this before?'"

When compared to bees, humans have a rather simplistic sex-determination process. In females, the two sex-determination chromosomes are  the same, and in males the two chromosomes are different. With bees, however, the combinations of complementary sex determination genes, or CSDs, determine the sex and the societal role of the bees.

One particular gene can have alleles - the "flavor" of genes. In humans, they dictate hair and eye color. In bees, though, they are responsible for creating females (worker bees), fertile males (that mate with the queen) or infertile males (diploid males which serve no purpose).

The viola moment came once Huang estimated the bees' mating habits and the potential of CSD allele combinations. That's when he understood why he couldn't confirm the founder effect. Keeping the CSD mix diverse is one of the keys to maintaining a healthy hive, he said.

The island queens carry around 40 CSD alleles. Since they mate with nearly 100 males - each also harboring around 40 alleles - the high number of healthy genetic combinations keeps the gene pool diverse. By using natural selection to create healthy offspring, the bees perpetuate a healthy colony.

In comparison, if the island bees adopted the breeding habits of fire ants, with queens mating with a single male, inbreeding could wreck the off-shore claves or distinct populations of bees. The devastating change would  reduce the fitness of the hive, decreasing the female workforce, as well as lowering the number of mating males.

What would be left would be an unhealthy hive with higher numbers of diploid or infertile males, with the same alleles, Huang said.

By extending his research beyond Hainan Island, Huang found evidence that showed that the island wasn't an isolated case.

"We failed to find any clustering of the bees' CSD alleles according to their geographical origin; the Hainan and mainland bees did not form separate clades," said Huang, whose research is supported y MSU AgBioResearch. "Previously published CSD  sequences also failed to show any unique clade-forming in the Philippines and Malaysia."