> My understanding is that domestication manifests through loss of genetic diversity. In this study, they argue that honeybees have gained genetic diversity, thereby relegating them to managed wild stock rather than domestic breeds.
Hi Bill
I agree, but the question arises: how do we measure genetic diversity? Currently, different samples have their DNA mapped and compared using computer software that looks for similarities and differences. Two examples:
> Samples from nine populations belonging to three African (intermissa, scutellata and capensis) and four European (mellifera, ligustica, carnica and cecropia) Apis mellifera subspecies were scored for seven microsatellite loci. A large amount of genetic variation (between seven and 30 alleles per locus) was detected. Average heterozygosity and average number of alleles were significantly higher in African than in European subspecies, in agreement with larger effective population sizes in Africa. -- Estoup, 1995
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> The African population had the highest level of diversity followed by the southern Californian populations. The domesticated drone grouping showed the lowest nucleotide diversity in California. The southern populations appear to be more genetically diverse, likely due to the recent contribution from African-derived alleles. There are more differences between the Avalon population and the mainland populations than between the all mainland populations, further supporting the idea that the Avalon population has remained genetically isolated from the mainland for a relatively long period of time. -- Cridland, 2018
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comments:
The populations with the lowest diversity were domesticated California bees and isolated bees on Catalina island. The most diverse were from large wild populations living in Africa. So, diversity can be significantly reduced by isolation from either closed breeding or in an island population, like Catalina (or Sardinia, Cyprus, etc.). An island population would have high susceptibility to extinction from pests or pathogens, such as the honey bees of nearby Santa Cruz Island, which were deliberately eradicated using Varroa. Conversely, native bees in Africa quickly evolved low susceptibility to Varroa, showing the resilience of diverse populations/
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