What is fitness?

[thoughtful (Valerie (non-scientist))]

@T_aquaticus

However, people who have two copies of the HbS allele can also suffer from sickle cell anemia, so there is stronger selection against the allele in areas without malaria. The global distribution of the allele has everything to do with natural selection, both positive and negative selection.

Yes, that was my understanding, just poorly worded.

@T_aquaticus

The stabilization process is negative selection against harmful mutations.

Oh…you’re making Sanford’s argument for natural reservoirs! That’s a good one!