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|Title:||Genetic Variation and Differentiation in Honey Bees (Apis) (Electrophoresis)|
|Author(s):||Sheppard, Walter Steven|
|Department / Program:||Entomology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The natural distribution of the genus Apis is limited to Europe, Africa and Asia. Therefore, New World populations of A. mellifera, the familiar honey bee of commerce, are descended from importations that began with early European colonization in the Americas. In the Old World, at least two dozen geographical races of A. mellifera are known to occur. Historical records of introduction indicates that only eight of these races were ever introduced into the United States.
Genetic bottleneck effects are often associated with colonization events. The existence of a possible bottleneck in the honey bee was investigated by comparing genetic diversity of endemic European races with populations of A. mellifera from the U.S. Samples of A. m. mellifera, A. m. ligustica and A. m. carnica were obtained from Norway, Italy and Czechoslovakia, respectively, and electrophoresis revealed several new enzyme polymorphisms (malic enzyme, aconitase, phosphoglucomutase) and additional allelic variation (malate dehydrogenase, esterase) not previously known from U.S. honey bees. Electrophoretic analysis of feral and commercial colonies of U.S. A. mellifera revealed a loss of variation compared to European samples. The existence of the Mdh('80) allozyme in high frequency in U.S. feral colonies suggests the genetic influence of A. m. mellifera, the first race to be imported. The overall heterozygosity (Hexp) for European honey bees was 0.038, compared to 0.010 reported for U.S. bees.
A phylogenetic examination of the genus Apis was undertaken using electrophoresis to supplement traditional morphometrics. In addition to European A. mellifera, samples of A. dorsata, A. florea, and A. cerana were obtained from Sri Lanka, where they co-occur within their natural ranges. This study represents the first comprehensive survey of genetic variation in the genus, exclusive of A. mellifera. A number of polymorphisms were detected in the species and the mean genetic distance among the species (Nei unbiased = 1.30) supports estimates for the antiquity of the genus (20-30 mya) made from the fossil record. The extensive electrophoretic differentiation of the species will make it possible to answer a number of questions that still remain concerning the genus, especially the status of a number of proposed new species.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1986.
|Date Available in IDEALS:||2014-12-16|