Abstract:
Western honey bees (Apis mellifera) far exceed the commonly observed 1–2 meiotic recombination events per chromosome and
exhibit the highest Metazoan recombination rate (20 cM/Mb) described thus far. However, the reasons for this exceptional rate of
recombination are not sufficiently understood. In a comparative study, we report on the newly constructed genomic linkage maps of
Apis florea and Apis dorsata that represent the two honey bee lineages without recombination rate estimates so far. Each linkage
mapwasgeneratedde novo,basedonSNPgenotypesofhaploidmaleoffspringofasinglefemale.TheA. floreamapspans4,782 cM
with 1,279 markers in 16 linkage groups. The A. dorsata map is 5,762 cM long and contains 1,189 markers in 16 linkage groups.
Respectively, these map sizes result in average recombination rate estimates of 20.8 and 25.1 cM/Mb. Synteny analyses indicate that
frequent intra-chromosomal rearrangements but no translocations among chromosomes accompany the high rates of recombination during the independent evolution of the three major honey bee lineages. Our results imply a common cause for the evolution of
very high recombination rates in Apis. Our findings also suggest that frequent homologous recombination during meiosis might
increase ectopic recombination and rearrangements within but not between chromosomes. It remains to be investigated whether
the resulting inversions may have been important in the evolutionary differentiation between honey bee species