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From:
Peter Loring Borst <[log in to unmask]>
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Informed Discussion of Beekeeping Issues and Bee Biology <[log in to unmask]>
Date:
Sat, 28 Mar 2015 08:31:56 -0400
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> What is your take on that specific question?

I am not sure what the impact of selection is on mitochondria. Mitochondrial dna varies slowly and so is used to trace lineages back tens of thousands of years. Genomic dna, especially in the honeybee, recombines at a very high rate. I am not sure we influence this as much as we think. 

> Most unique features of mtDNA are its maternal inheritance and lack of recombination: the complexities imposed by recombination of paternal and maternal genomes can be excluded in reconstructing evolutionary histories. MtDNA population studies have shown that human migrations and genetic drift were responsible for the current distribution of maternal lineages across the world as well as the regional variation of human mtDNA’s. 

> However, it cannot explain the enrichment of lineages A, C, D, and G in arctic region and the fact that only two mtDNA lineages (M and N) left Africa to colonize Eurasia. That contradiction thus gave rise to an alternative hypothesis: natural selection. -- Huang, S., Wang, C., & Li, H. (2014). Natural selection on human mitochondrial DNA. Biotechnology Frontier, 3(1).


Relative small effective population sizes of social insects
may promote the evolution of high recombination under
selection, especially in haplo-diploid species where recessive
alleles are expressed in the haploid sex.

However, they also suggest a purely mechanistic cause:

In contrast to adaptive explanations, the high recombination
rate might also be explained mechanistically.
The GC content of the honey bee genome is only
33% on average with a strong bimodal distribution ranging
from 10-70% [20] and genes are overly abundant in
genome regions with lower than average GC content. 
Thus, DNA structure and accessibility may be one
mechanistic explanation. '

GC content may be the most important determinant of local
recombination rates in the honey bee genome

Ross, C. R., DeFelice, D. S., Hunt, G. J., Ihle, K. E., Amdam, G. V., & Rueppell, O. (2015). Genomic correlates of recombination rate and its variability across eight recombination maps in the western honey bee (Apis mellifera L.). BMC genomics, 16(1), 107. Chicago	

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