Genes evolve to adapt to excess or low vitamin D (Eskimo, Reindeer, etc.)
Note: It probably takes many 1,000's of years for the genes to adapt
Reindeer genes are 20X better at activating Vitamin D than other mammals
Biological adaptations in the Arctic cervid, the reindeer (Rangifer tarandus) - June 2019
📄 Download the PDF fromSci-Hub via VitaminDWiki

POR = P 450 O xido r eductase
Suspect also that Reindeer have gene modifications which increase the Vitamin D half life from ~2 months to > 5 months
Genetics category listing contains the following
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