Getting the buzz on the value of bees
Box 2 | Epigenetics
Honeybees offer an insight into the interaction between genetic factors and the environment in shaping the development of an individual. Australian researchers are using them to become world leaders in this exciting new field of research.
larvae from royal jelly packed queen cells. Note how
theyare much larger than the ordinary cells within the
honeycomb frame. (Credit: Ryszard Maleszka,
Australian National University.)
You are what you eat
In a colony of European honeybees, any female egg can develop into a queen – depending on her diet. Early on, all bee larvae are fed a substance called royal jelly, which is a gelatinous substance produced in the head glands of ‘nurse’ bees. Royal jelly is composed of approximately two-thirds water, one-eighth proteins, 11% simple sugars and quantities of Vitamin C and various trace minerals and enzymes.
After three days, those larvae destined to become workers or drones receive no more royal jelly; instead, their diet switches to bee bread (a mixture of pollen, nectar and honey). In contrast, those larvae chosen to become queens are fed only royal jelly for the remainder of their lives.
This exclusive diet of royal jelly triggers the development of queen bees and it involves what is known as an epigenetic process. Epigenetics is the study of the way in which the environment affects gene expression. The larvae that develop into queen bees or worker bees are genetically identical yet as adults they are so different they appear like completely different organisms – worker bees are smaller, infertile, have different organs, anatomy and behaviour, die after stinging and are relatively short lived (typically, active workers live between five and seven weeks, whilst queen bees can live four to five years).
Royal jelly is an incredibly complex substance and it contains many unusual and still poorly understood compounds. These including royalactin and several histone acetylase inhibitors, which are known to influence gene expression. The complex chemicals in royal jelly act to alter the expression of certain genes by suppressing a biochemical process called DNA methylation.
larvae are having their genes manipulated as part of
DNA methylation silencing experiments.
(Credit: Ryszard Maleszka, Australian National University.)
Australian research into epigenetics
Epigenetics provides a method of seeing exactly what happens to certain pre-identified gene markers when they are exposed to chemicals over one or more generations. Bees provide excellent models for this work as they are much simpler organisms than mammals or humans and they are relatively quick to breed.
A team of Australian researchers, led by Ryszard Maleszka at the Australian National University, is using the European honeybee as a model for better understanding the effects of environmental factors on gene expression. Molecular processes that are common across all organisms are highly conserved, so bees share some similar genes and biochemical mechanisms with humans. Therefore, this research could lead to new understanding of a wide range of issues related to honeybees but also to the wider environmental health of other animals including humans. For example it could address questions such as: do pesticides, medicines, narcotic drugs or other chemicals have an epigenetic effect, and are these effects passed on to subsequent generations? How does the diet or lifestyle choice of a parent influence the expression of genes in their children, or their children’s children? Answering these questions could provide clues as to how genomes are linked to the environment and how external changes can activate pathways that modify the global expression of an organism, leading to new advances in medicine and environmental health.
Boxes
Box 1. Native bees
Box 3. Ensuring sufficient pollinators
Box 4. Fighting the Varroa mite
Related sites
Epigenetics – beyond genes
Maleszka Lab - From molecules to behaviour
Being Queen
Royal Jelly Makes Bee Queens, Boosts Nurture Case
A Queen is made not born: Epigenesis in honey bees.
You are what you eat: Royal jelly is yielding clues to human disorders.
External sites are not endorsed by the Australian Academy of Science.
Posted August 2011.