Biology Reference
In-Depth Information
search. (It is interesting that the Austrian friar who discovered the
fundamental principles of genetic inheritance, Gregor Mendel, worked
with garden peas for seven years and began the i eld of genetics. He
spent the rest of his life unsuccessfully trying to breed a better honey
bee. He failed because he could not control the promiscuous mating
of the queen.) h e third was the completion of the honey bee genome
sequence due to the huge ef ort of Gene Robinson. h e genome se-
quence of the honey bee consists of more than 200 million base pairs
(the building blocks of DNA), one-tenth the size of the human genome,
and contains about 10,000 genes. h e human genome contains about
20,000 genes. Besides opening up the honey bee to even more detailed
and complete genetic analysis, the genome sequence has attracted
geneticists working on other organisms into the community of bee
research.
h e honey bee genome sequence enabled us to search for positional
candidate genes, genes in the regions of the chromosomes where our
mapping studies of pollen-hoarding QTLs indicated that there is a gene
or genes af ecting our phenotypes. Statistical techniques allowed us to
identify coni dence limits around the locations on the chromosomes
where our maps suggested that QTLs reside. We looked at the 97 per-
cent coni dence limits. h is means that if you run the whole mapping
experiment 100 independent times, 97 times the interval contained in
the coni dence limit will contain the gene you are looking for. We
looked at the honey bee genome sequence within the coni dence limits
of our QTLs and identii ed all the known or suspected genes in those
regions. Altogether we identii ed 116 candidates: 18 for
pln1,
63 for
pln2,
32 for
pln3,
and 3 for
pln4.
h is is a huge reduction from the esti-
mated 10,000 genes in the honey bee genome, but still too many to at-
tempt to verify individually.
While Greg Hunt and Gro Amdam were looking at the list of candi-
date genes, they noticed that there was an overrepresentation of one set
of genes that are involved in one signaling cascade. h is cascade is
known as the insulin-insulin-like signaling (IIS) pathway. It is ancient
and ubiquitous, spread throughout the animal kingdom, including hu-
mans, insects, and worms. Signal cascades like the IIS network have
