| Summary: | <p>Abstract</p> <p>Background</p> <p>The bumblebee <it>Bombus terrestris </it>is an ecologically and economically important pollinator and has become an important biological model system. To study fundamental evolutionary questions at the genomic level, a high resolution genetic linkage map is an essential tool for analyses ranging from quantitative trait loci (QTL) mapping to genome assembly and comparative genomics. We here present a saturated linkage map and match it with the <it>Apis mellifera </it>genome using homologous markers. This genome-wide comparison allows insights into structural conservations and rearrangements and thus the evolution on a chromosomal level.</p> <p>Results</p> <p>The high density linkage map covers ~ 93% of the <it>B. terrestris </it>genome on 18 linkage groups (LGs) and has a length of 2'047 cM with an average marker distance of 4.02 cM. Based on a genome size of ~ 430 Mb, the recombination rate estimate is 4.76 cM/Mb. Sequence homologies of 242 homologous markers allowed to match 15 <it>B. terrestris </it>with <it>A. mellifera </it>LGs, five of them as composites. Comparing marker orders between both genomes we detect over 14% of the genome to be organized in synteny and 21% in rearranged blocks on the same homologous LG.</p> <p>Conclusions</p> <p>This study demonstrates that, despite the very high recombination rates of both <it>A. mellifera </it>and <it>B. terrestris </it>and a long divergence time of about 100 million years, the genomes' genetic architecture is highly conserved. This reflects a slow genome evolution in these bees. We show that data on genome organization and conserved molecular markers can be used as a powerful tool for comparative genomics and evolutionary studies, opening up new avenues of research in the Apidae.</p>
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