The Ramírez Lab

University of California - Davis

Populations Genomics of Honey Bees

The western honey bee (Apis mellifera L.) is native to Africa, Asia and Europe, where at least four distinct mitochondrial lineages have been identified (namely M, C, O and A). The earliest evidence of introduced honey bees in the U.S. dates back to the 1600s, and presumably consisted of bees belonging to the M lineage. Subsequently, between 1859 and 1922 (before the honey bee Act restricted importations to prevent the spread of parasitic mites) additional honey bee subspecies were introduced to North America, including domesticated (C and O) and African (A) lineages. Honey bees have endured regular epidemics of pathogens and parasites, including the mysterious Colony Collapse Disorder. In collaboration with Neil Tsuitsui, we are currently sequencing whole genomes (with Illumina technology) from ethanol-preserved specimens collected in California over the past 130 years. Using Single Nucleotide Polymorphisms (SNPs) derived from across the honey bee genome, we are determining admixture and introgression levels.

As we continue to develop genomic resources for our other study species (orchid bees and euglossine-pollinated orchids), we hope to apply some of these genome-wide methodologies to study the processes of adaptation and speciation in natural populations in select lineages.