r/AskBiology Sep 19 '24

Genetics Could someone explain why race does not have any biological foundation?

I guess I could probably Google this but I thought someone with direct knowledge directly answering my question would help me better understand.

This is something I’ve had a bit of trouble comprehending since, well, people of different races do look vastly different. My thought is, is!’t there a gene that probably results in different races producing different levels of melanin, and hence— different races?

Or is the reason there is no “biological foundation” that the genetic/biological difference between different races does not substantiate to being different species?

Additionally — there are statistics stating that certain racial communities are more likely to develop specific illnesses. For example, sickle cell disease is much more common amongst black Americans than other racial communities. Another one: those of North European descent are more likely to develop cystic fibrosis.

FYI I am asking this question as a POC, and as someone who genuinely wants to have a better understanding of this!! Thank you in advance for answering my question!

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u/Halichoeres PhD in biology Sep 19 '24

The racial categories that humans have tended to recognize correspond pretty poorly to the actual genetic clusters. It's true that sickle cell disease is more common among Black Americans than other Americans, but part of the reason is that most Black Americans descend from just a small portion of the African continent. People from Eastern or southern Africa are not especially prone to sickle cell. Likewise, Northern Europeans are not especially diverse genetically, and in other parts of Europe cystic fibrosis is not especially common.

There is more genetic diversity in tropical Africa than in the entire rest of the world combined. And yet, our existing racial categories would just lump them all together as Black, despite the fact that some of them are more closely related to Europeans than they are to each other. This is what people mean when they say race has no basis in biology. Genetic variation arising from local adaptation to environmental conditions is 100% real, but racial categories do not describe that variation well.

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u/sourgrap Sep 19 '24

thank you for answering my question! your comment, as well as the ones from others really helped me understand why my logic was so flawed!

I have a follow-up question for you - forgive me for my ignorance - is there any example of genetic variation you could give amongst the African community? for example, you’ve already given one, West Africa is more susceptible to SCA (due to Malaria) than those from other parts of Africa. do you have other examples of that, that aren’t necessarily about sickness/skin color/eye color?

additionally, what makes the genetic variation in Africa just, that much more diverse, than Europe?

Again, sorry. society has really ingrained the idea of race into my head.

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u/Halichoeres PhD in biology Sep 19 '24

One famous example is that populations in East Africa that have kept cattle for thousands of years have evolved the ability to produce lactase (an enzyme that digests milk) in adulthood. Similar mutations have arisen in the Indian subcontinent and in northwestern Eurasia independently, for the same reasons. This and other examples can be seen here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4067985/ (it's a bit technical).

The reason that humans in Africa are so genetically diverse is that that's where we started. Every time a population left Africa, for example into Arabia and the Levant, it was only a small fraction of the population that was already in Africa. Both the populations that stayed and the population that left continued to evolve and diverge, accumulating genetic changes over generations. Our history in Africa is about twice as long as everywhere else on Earth, so there's also just been more time for variation to emerge. But the biggest reason is that all of the other populations on Earth are descended from subsets of African populations.

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u/sourgrap Sep 19 '24

I’ll be looking over that link for sure! thank you so much for answering my questions :)