The map is a bit stupid. There is no reason to have that difference in Iceland, Svalbard or Novaya Zemlya, which isn't even populated. I think they just measured at the dots and made some extrapolation for the rest of the map.
Mining companies? Primary industry related? Cause the biggest circle there for Australia is on our Western side which is where a lot of Mining companies are headquarted.
fyi (since nobody got it even close to right) this is distribution of CCR5-Δ32 mutation, which gives immunity to HIV when on both chromosomes (recessive allele) (so real rate of immunity is square of that percentage, about 1% in areas of highest prevalence)