Genetic diversity and structure in a closed breeding system of Russian honey bees

Authors: Bilodeau, Lanie

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2021
Publication Date: 1/25/2022
Citation: Bilodeau, A.L. 2022. Genetic diversity and structure in a closed breeding system of Russian honey bees. Journal of Economic Entomology. 115(2):682-687. https://doi.org/10.1093/jee/toab266.
DOI: https://doi.org/10.1093/jee/toab266

Interpretive Summary: Genetic diversity is a critical component of a successful breeding program. Russian honey bees are a selected stock developed by the USDA. The stock is comprised of 16 lines that are divided into 3 blocks for breeding purposes. Maintenance of diversity among the blocks is important to avoid inbreeding and for the breeding program to succeed. Diversity was assessed in 3 breeding year classes spanning a total of 6 years to examine the genetic structure of the blocks and to detect any changes over time. Diversity levels were consistent for all years sampled and among blocks. Structure was present, with the final year class showing increased levels of population structure in comparison to the previous year classes. The patterns observed were consistent with the history of the stock.

Technical Abstract: High levels of genetic diversity are critical to the success of breeding programs. Russian honey bees are a selected stock that undergoes breeding in a closed block-based mating system. Given its established history, Russian stock has longitudinal measures of genetic integrity (i.e., genetically-based stock identity) and diversity. Assessments using genetic stock identification (GSI) have shown that Genetic diversity parameters were assessed across breeding blocks for 3 generations, spanning 6 years (2014, 2017, 2020), showing levels comparable to those when the stock was initially released in 2008. Allelic richness (mean number of alleles) and gene diversity levels were consistent over time and among blocks. Blocks were generally not differentiated from one another within each year. However the 2020 population was distinct when compared to bees sampled in both 2014 and 2017. Genetic distance relationships supported differentiation of the 2020 population by distinct clustering. The patterns observed here are consistent with historical changes made to the breeding program to increase stringency of the selection criteria.