Editing Africanized bee (section)

===Western variants===
The western honey bee is native to the continents of Europe, Asia, and Africa. As of the early 1600s, it was introduced to North America, with subsequent introductions of other European subspecies 200 years later.<ref>{{cite web |url=https://www.sciencedaily.com/releases/2006/12/061211220927.htm |title=Research upsetting some notions about honey bees |website=[[ScienceDaily]] |date=29 December 2006}}</ref> Since then, they have spread throughout the Americas. The 29&nbsp;subspecies can be assigned to one of four major branches based on work by Ruttner and subsequently confirmed by analysis of [[mitochondrial DNA]]. African subspecies are assigned to branch&nbsp;A, northwestern European subspecies to branch&nbsp;M, southwestern European subspecies to branch&nbsp;C, and Mideast subspecies to branch&nbsp;O. The subspecies are grouped and listed. There are still regions with localized variations that may become identified subspecies in the near future, such as ''A. m. pomonella'' from the [[Tian Shan]] Mountains, which would be included in the Mideast subspecies branch.

The [[western honey bee]] is the third insect whose [[Gene mapping|genome has been mapped]], and is unusual in having very few [[transposon]]s. According to the scientists who analyzed its genetic code, the western honey bee originated in Africa and spread to Eurasia in two ancient migrations.<ref>{{Cite journal |doi=10.1126/science.1132772 |pmid=17068261 |title=Thrice out of Africa: Ancient and recent expansions of the honey bee, ''Apis mellifera'' |journal=Science |volume=314 |issue=5799 |pages=642–5 |year=2006 |last1=Whitfield |first1=C.W. |last2=Behura |first2=S.K. |last3=Berlocher |first3=S.H. |last4=Clark |first4=A.G. |last5=Johnston |first5=J.S. |last6=Sheppard |first6=W.S. |last7=Smith |first7=D.R. |last8=Suarez |first8=A.V. |last9=Weaver |first9=D. |last10=Tsutsui |first10=N.D. |bibcode=2006Sci...314..642W|s2cid=15967796 }}</ref> They have also discovered that the number of genes in the honey bee related to smell outnumber those for taste.<ref name='genome'>{{Cite journal |doi=10.1038/nature05260 |pmid=17073008 |title=Insights into social insects from the genome of the honeybee ''Apis mellifera'' |journal=Nature |volume=443 |issue=7114 |pages=931–949 |year=2006 | last1 = Weinstock | first1 = G. M. | last2 = Robinson | first2 = G. E. | last3 = Gibbs | first3 = R. A. | last4 = Worley | first4 = K. C. | last5 = Evans | first5 = J. D. | last6 = Maleszka | first6 = R. | last7 = Robertson | first7 = H. M. | last8 = Weaver | first8 = D. B. | last9 = Beye | first9 = M. | last10 = Bork | first10 = P. | last11 = Elsik | first11 = C. G. | last12 = Hartfelder | first12 = K. | last13 = Hunt | first13 = G. J. | last14 = Zdobnov | first14 = E. M. | last15 = Amdam | first15 = G. V. | last16 = Bitondi | first16 = M. M. G. | last17 = Collins | first17 = A. M. | last18 = Cristino | first18 = A. S. | last19 = Michael | first19 = H.| display-authors = 18 | pmc=2048586|bibcode = 2006Natur.443..931T }}</ref> The genome sequence revealed several groups of genes, particularly the genes related to [[circadian rhythms]], were closer to vertebrates than other insects. Genes related to enzymes that control other genes were also vertebrate-like.<ref>{{Cite journal | doi = 10.1126/science.1135213 | pmid = 17068262 | title = Functional CpG methylation system in a social insect | journal = Science | volume = 314 | issue = 5799| pages = 645–647 | year = 2006| last1 = Wang | first1 = Y. | last2 = Jorda | first2 = M. | last3 = Jones | first3 = P. L. | last4 = Maleszka | first4 = R. | last5 = Ling | first5 = X. | last6 = Robertson | first6 = H. M. | last7 = Mizzen | first7 = C. A. | last8 = Peinado | first8 = M. A. | last9 = Robinson | first9 = G. E. | bibcode = 2006Sci...314..645W| s2cid = 31709665 }}</ref>