Professor Gene Robinson led the world consortium that deciphered the 236-million-base genome of the European honey bee Apis mellifera. This was described in the 26 October 2006 issue of Nature. Several intriguing aspects emerged from this and accompanying work.
With just a million neurons (several orders of magnitude less than humans), the bee brain is relatively simple, yet socially sophisticated. The honey bee has a vertebrate-like set of enzymes needed to methylate genes (modification for purposes of controlling gene expression), implying that methylation may be important in silencing genes in bees as well as in vertebrates, including humans.
Genomics studies are tracing the roots of bees in general, and honey bees in particular, to Africa. The primitive, or primary, bee lineages are most diverse in Africa, indicating that's where this group likely arose.
Analysis of 1,500 single-nucleotide polymorphisms (SNPs)-(differences of a single DNA out of mitochondrial DNA), found there are four subspecies of honey bees: two in Europe, one in Asia, and one in Africa.
Subsequently, there have been multiple introductions of various subspecies by humans into the New World. The SNP data reveals how these clusters arose from two "out of Africa" migrations. Interestingly, despite their geographic proximity, the two European groups are the most different, indicating they arose independently of each other, one from a west Mediterranean crossing, and the other from the east.
The honey bee has 165 odorant-receptor genes, more than double what Drosophila (fruit flies) and Anopheles (mosquitos) have. This expansion makes sense, given the bee's need to recognize kin and find suitable flowers. In a way, this is reminiscent of human beings' rapid expansion of gene expression profiles associated with intricate large social-group interactions, especially in areas of communication skills.
