Agriculture Reference
In-Depth Information
Genetic variability
While sex determination is, therefore, generally complicated, other characteristics can
be even more complex. Different combinations of alleles at a locus can result in many
different expressions of characteristics, and all these different factors result in complex
genetic systems that produce a wide variety of character expressions in bees. Alleles at
other loci can also affect a characteristic, but from this variety comes some of the raw
material necessary for the genetic improvement of bee stocks.
So far we have looked at the genetic make-up of queens and drones and have explored
how these genetic characteristics can affect colonies. A key factor in all this is the
number of chromosomes in bees. To summarize so far, therefore (see also Figure 31):
Fig. 31.
The number of chromosomes in bees
Drones result from unfertilized eggs by a process known as parthenogenesis. They
have no father.
Eggs and sperm carry 16 chromosomes each.
Each egg contains a unique combination of 50% of the queen's genes, and sperm
contains 100% of the drone's genes.
Almost all the 10 million sperm produced by a drone are identical clones. As a
drone results from a queen only, he inherits her characteristics, converting her egg
into sperm and carrying this to another queen.
