European DNA & the Rare Rh-Negative Blood Type…

Join This Channel on YouTube to Get Access to Perks:    / @celtichistorydecoded  

Get Access to Member-Only Videos & More Perks on Patreon -   / historydecoded  

Subscribe to Celtic History Decoded -    / @celtichistorydecoded  

European DNA & the Mysterious Rh-Negative Blood Type…

Chapters:
0:00 Intro
0:19 Rates of Rh-Negative Around the World
2:22 Genetics of Rh-Negative
4:09 Rh Incompatibility During Pregnancy
5:04 Why Rh-Negative?
12:30 Become a Member and Get Perks

Only around 6% of the global population is Rh-negative. Yet 15–17% of Europeans have this rare blood type, the highest levels in the world compared to other regions. Why is it so common amongst Europeans though? How did Rh-negative first develop? And what are the reasons for this rare and mysterious blood type in general?

Now certain populations of Europe have especially high frequencies of this blood type. The Basque people of Spain and France are the prime example. They have the highest rates of Rh-negative in the world, at between 21% and 36% of Basques. Britain also has pretty high levels, as about 17% of British people are Rh-negative. Outside Europe, Rh-negative blood is much rarer however. Look at this table. It shows the highest to lowest Rh-negative rates in the world.

In most of Asia, less than 1% of individuals are Rh-negative, in places like China and Japan. Indigenous populations of the Americas and Oceania also have very low Rh-negative frequencies (often well below 1%. You can see Native Americans at the bottom of this table). I should note that in the United States overall, around 15% of people are Rh-negative. Yet we know there are a lot of people of European ancestry in the US which perhaps explains this to some degree. Africa shows more variability: many sub-Saharan African populations have Rh-negative rates of only 1–3%. North African and some specific groups can be higher though. For example, one study found about 9.5% of Moroccans were Rh-negative, and even ~29% in a small isolated group in the High Atlas region of Morocco. Ethiopians are also pretty high, at around 19.4% according to one estimate. Nigeria sits somewhere in the middle at around 6%, with African Americans similar around 7%.

So although there are certain countries or areas outside of Europe where Rh-negative is high, Europe stands out overall as a hotspot for this trait. This leads to the obviously question: what is it about European DNA that makes this trait much more common than so many other parts of the world? And is there anything specific about Basque DNA that can help us understand this dynamic? Before we look at the fascinating explanations for this though, we first must look at the genetic basis and inheritance of the Rh-negative trait.

Now in general there are four main blood group types in the ABO blood group system, which are:

Sources:

Iain Mathieson (2017) - Blood groups in ancient Europe

T. Günther, et al. Ancient genomes link early farmers from Atapuerca in Spain to modern-day Basques, Proc. Natl. Acad. Sci. U.S.A. 112 (38) 11917-11922, https://doi.org/10.1073/pnas.1509851112 (2015).

Blood groups of Neandertals and Denisova decrypted | PLOS One
Flores-Bello, A., Mas-Ponte, D., Rosu, M.E. et al. Sequence diversity of the Rh blood group system in Basques. Eur J Hum Genet 26, 1859–1866 (2018). https://doi.org/10.1038/s41431-018-02...

Flegel WA. The genetics of the Rhesus blood group system. Blood Transfus. 2007 Apr;5(2):50-7. doi: 10.2450/2007.0011-07. PMID: 19204754; PMCID: PMC2535884.

Population distribution of Rh-negative blood and allele frequencies Rh blood group system - Wikipedia

Condemi S, Mazières S, Faux P, Costedoat C, Ruiz-Linares A, Bailly P, et al. (2021) Blood groups of Neandertals and Denisova decrypted. PLoS ONE 16(7): e0254175. https://doi.org/10.1371/journal.pone....

Rhesus (Rh) Factor: Incompatibility, Complications & Pregnancy

SELECTION AGAINST HETEROZYGOSIS IN MAN (1941) J. B. S. HALDANE F.R.S.

Chart: How Blood Type Prevalence Varies Around the World | Statista

Creative Commons Imagery:

Wojciech Pędzich, Robert Molyneaux File:Yamnaya phenotype, Reconstruction, male, grave Novooleksiivka; Ukraine.png - Wikimedia Commons Creative Commons Attribution-Share Alike 4.0 International license. Deed - Attribution-ShareAlike 4.0 International - Creative Commons

Matteo De Stefano/MUSE File:Homo sapiens - Neolithic - reconstruction - MUSE.jpg - Wikimedia Commons Creative Commons Attribution-Share Alike 3.0 Unported license. Deed - Attribution-ShareAlike 3.0 Unported - Creative Commons

Maulucioni File:Haplogrupo R1b (ADN-Y).png - Wikimedia Commons Creative Commons Attribution-Share Alike 4.0 International license. Deed - Attribution-ShareAlike 4.0 International - Creative Commons

#dna #ancestry #rhnegative