Signals of Ancestry-Specific Selection in Gentle Africanized Honey Bees

Understanding the genetic basis of adaptive responses to environmental and human mediated pressures is a central concern in evolutionary biology. Population admixture, a process wherein genetically differentiated populations interbreed, is increasingly recognized as a source of genetic material driving rapid evolutionary responses. Honey bees from Puerto Rico are a phenotypically distinct population of Africanized honey bees with demonstrably lower levels of aggression than other Africanized populations. The Puerto Rican honey bee population represents a dynamic system that has experienced both environmental and human-mediated selective pressures over a short period of time marked by a significant influx of genetic variation from mainland Africanized honey bees, which has notably influenced the genetic makeup of the local populations. In this study we detail the current population structure of the Puerto Rican honey bees, how this differs from a mainland population, and regions of the genome that have signals of ancestry-specific selection. To distinguish loci undergoing ancestry-specific selection, we use tools that co-estimate local ancestry and the strength of selection at loci across the genome. We further detail the genes and pathways highlighted through gene ontology (GO) enrichment analysis. Overall, our results suggest that the local pressures on Puerto Rico honey bee behavior may have induced significant changes favoring alleles linked to different ancestries at loci and pathways involved in neuronal development, behavior, and mating among others. Our analysis demonstrates that approaches that explicitly model selection on local ancestry may be valuable tools for understanding evolution in admixture zones.