i'm not talking about rus, but in general, evolution doesnt allways take the neccecary best way, it takes the easyest way
For example, in 70% of the african continent, people who have the sickle cell genetic disorder, or are heterozygote and have the trait, are outgrowing people who dont have it.
This because a person with sickle cell syndrome is immume to the malaria parasite, who cannot sustain itself in the HGa.
Thing is, one who has sickle cell syndrome, in optimal conditions, has a lifespan of maximum 30 years