London, March 14 : Scientists have identified the key factor that determines which bee larvae will turn into queens - royal jelly.
Dr Ryszard Maleszka and colleagues from the Australian National University in Canberra suggest that eating royal jelly destines honeybee larvae to become queens instead of workers.
They say the findings could provide clues on how the environment interacts with genes to produce obesity, longevity, sterility and brain disorders in humans.
"The larvae that develop into workers and queens are genetically identical," ABC Online quoted Maleszka, as saying.
Yet he says that those fed on royal jelly become fertile queen bees and are much larger and longer-lived than the rest that turn into sterile workers.
The researchers discovered that a copious diet of royal jelly flicks a genetic switch in young bees that determines whether they'll become a queen, or live a life of labour.
Royal jelly is a food substance secreted by adult bees that is fed in some measure to all young bees.
The researchers revealed that royal jelly seems to chemically modify the bees' genome by a process called DNA methylation, and disrupts the expression of genes that turn young bees into workers.
The team wanted to test the idea that royal jelly controls queen and worker development via epigenetics. Epigenetics involves chemical modification of the genome to change gene expression, and provides a way for the environment to affect an organism's genetics.
Maleszka said that the sequencing of the honeybee genome in 2006 revealed genes that mediate epigenetic effects in mammals.
One of these genes codes for the enzyme is DNA methyltransferase (Dnmt3) that in mammals suppresses the expression of particular genes by attaching a methyl group to them.
The researchers tested what happened when they silenced the Dnmt3 gene in hundreds of larvae. When the Dnmt3 gene was silenced, most of the larvae turned into queens. When the Dnmt3 gene was active, most of the larvae turned into workers.
"When we silenced a gene controlling DNA methylation without recourse to royal jelly, we discovered that the larvae began to develop as queens with the associated fertility, rather than as infertile workers," Maleszka said.
Dr Maleszka and his colleagues said this is the first time that DNA methylation - a molecular process common in vertebrates, including humans - has been functionally implicated in insects.
The researchers will continue to study how DNA methylation affects bees, as they suspect the process could also be responsible for how the insects' brains develop, and therefore be connected to bee behaviour.
The study is published in the journal Science.