The Iberian honey bee (Apis mellifera iberiensis) has been intensely surveyed for genetic variation with different
markers ranging from morphology, allozymes, mitochondrial DNA (mt DNA), to microsatellites. Some of these
markers have revealed non-concordant complex patterns of genetic variation, which led scientists to evoke
competing hypotheses for the origin of Iberian honey bees. While complex patterns and underlying historical
processes are typical of hybrid zones, the use of more powerful molecular and analytical tools and the fine-scale
sampling promised to help dissecting the complexities of the Iberian hybrid zone. In this study, we conducted
a genome-wide sampling by genotyping over 384 SNPs (single nucleotide polymorphisms) and sequenced an
intergenic fragment of the mt DNA in 711 georeferenced honey bee samples collected across three North-South
transects in the Iberian Peninsula. Both mt DNA and SNP datasets were analyzed using spatial tools to represent
the structure generated by both types of molecular markers. We found concordant spatial patterns between
markers which led to rejection of the standing hypothesis of recent human introductions and selection as the
processes shaping Iberian honey bees patterns. This study shows that the fine-scale genomic and spatial analyses
can reveal patterns which would otherwise had been undetected.
