Agriculture Reference
In-Depth Information
Since each queen mates with 10-20 drones, colonies comprise subfamilies, each
having the same mother but different fathers.
Workers of the same subfamily are related by 75% of their genes.
This 'extra' close relatedness may explain the co-operative and altruistic behaviours
found in colonies.
It may also explain why workers forgo their own reproduction in favour of helping
their queen/mother raise more sisters. Their sisters are more closely related to
them than their own offspring would be (75% v. 50%).
Mitochondrial DNA
As a small digression, it is worthwhile looking at how genetics can be employed as an
investigative tool when tracing the lineage of bees. To track the lineage of bees - for
example, to work out if a bee is of a European type or an African type - researchers look
at the mitochondrial DNA.
Mitochondria are small organelles found in every living cell. Their job is to release
energy by burning sugar with oxygen. In this way they make respiration possible.
When a cell divides, the mitochondria divide as well, but the small amount of DNA
they have remains separate from the nucleus. Also, when the sperm and egg unite
at fertilization to create a new genetic composition, the mitochondrial DNA stays
unchanged. Mitochondria thus pass through generations without their DNA ever
being changed, except by occasional mutations. These changes slowly accumulate, and
it is these accumulations that enable scientists to differentiate bee lineages.
So far we have looked at the theory of bee genetics. In this section we explore what
we can do with this information. Can we breed better bees, just as farmers improve
cows and other livestock, for instance? Given the knowledge we now possess about the
subject, the answer to this must be yes. Remember, we can only skim the surface here,
but the following should give you an idea of how bee breeders go about their work. For
