Sickle cell/ lactase persistence?

Question

How has human cultural practices contributed to the evolution of the sickle cell allele or lactase persistence?

Answer 1

Dairy products are most compatible with Blood Type "B" adults. Hindus and Jews, are two cultures that have the highest percentage of Blood Type "B" adults, and have incorporated dairy products into their diets and traditions...

As the other poster suggested, the sickle cell allele protects one from malaria, yet for those who carry this gene, the anemia it produces can be fatal, so, though it's not under our control, it's best to carry it in a recessive form!

Answer 2

For lactase, we all have a lactase enzyme when we are born to digest the mother's milk. the enzyme used to disappear when we were done with our mother's milk. but we started domesticating animals, which led to drinking their milk. this eventually led to the enzyme not disappearing so we could digest this new milk. with people who are lactose intolerant, it is most likely the case that this enzyme disappeared, but not always.

For sickle cell anemia, this has to do with malaria. If you have sickle cell anemia you have a resistance to malaria. this would be beneficial in areas were malaria is common. but sickle cell anemia also kills you at a relatively young age. Therefore, it would be best to be heterozygous for sickle cell, so you would get only the benefits.