> Aye, there's the rub. Genetic drift can create distinctions between populations. This is not a mark of adaptation at all, it's drift.

Certainly possible, but as they note in the report this is unlikely due to the patterns that emerged among the results in populations from similar climates:

'Genetic drift is a stochastic mechanism that can change the frequency in alleles within a population regardless of the influence of ecological gradients. Although in this case, the type of micro-evolutionary process responsible is not directly demonstrated, the processes were found to cluster bi-directionally depending on climate of population origin. This indicates an extremely low chance that observations were the result of random genetic drift, as the same protein expression trends appear to be lost or gained in the opposing direction at each geographical origin.'

'If the populations studied here had adapted or were optimally bred to survive in the climate in which they were situated prior to transfer to the experimental site then one would expect a higher degree of similarity between colonies from areas with similar climates than between colonies from areas with different climates and, indeed, this was true.'

As they found:

'Of the processes that are over-represented, protein folding is evident in 4 populations, being up-regulated in both Californian (2nd term found) and down-regulated in all three Canadian populations.'

And in response to their results, the authors suggest:

'Overall, energy-related mitochondrial pathways were up-regulated in bees adapted to colder climates while protein biosynthesis and degradation pathways were preferentially up-regulated in honey bees from warmer climates. The observations reported here increase our understanding of metabolic diversity in honey bee populations and lay a framework for biomarker use in selective breeding.'

Lots of intriguing studies referenced in the paper in question. If there is continued interest in this topic, it could be interesting to dive into these papers here on Bee-L.

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