| Summary: | Tese de Doutoramento em Biologia Molecular e Ambiental - Especialidade em Evolução, Biodiversidade e Ecologia The goal of this study was to disentangle the complex variation patterns of the Iberian honey bee ( Apis mellifera iberiensis) hybrid zone using the highly polymorphic tRNAleu-cox2 mitochondrial region and nuclear genome-wide Single Nucleotide Polymorphisms (SNPs). Initially, a maternal analysis was performed using a PCR-RFLP marker, known as the DraI test, in the tRNAleu-cox2 intergenic region of colonies sampled in Portugal (N=950). Using this test, 16 novel haplotypes of African ancestry, 15 belonging to sub-lineage AIII and 1 to sub-lineage AI, were identified. This result suggests that the Atlantic side of the Iberian Peninsula is an important reservoir of maternal diversity that has been missed out because of under-sampling in previous studies. To obtain a fuller picture of maternal diversity patterns in the Iberian honey bee, 711 drones, sampled across three north-south Iberian transects, were screened for tRNAleu-cox2 variation using sequence data. The tRNAleu-cox2 sequence revealed a more complex diversity pattern of haplotypes in the Iberian honey bee than previously thought when using only the DraI test, which is reflected by detection of 164 novel haplotypes of African (lineage A) and Western European (lineage M) ancestry. At the same time, the distribution of haplotypes A and M reported in this study has further refined the well-defined Southwestern-Northeastern clinal pattern previously described, and also has rescued and reinforced the hypothesis of a hybrid origin for the Iberian honey bee. The distribution pattern of both lineages suggests the presence of two glacial refuges located in the Northeastern and Southern of Iberia. Nonetheless, the confined distribution of sub-lineage AIII to the North Atlantic side of Iberia suggests a putative third refuge, an hypothesis that deserves further investigation. A phylogenetic tree representing over 281 haplotypes, of which 8 exhibited ...
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