Blood types vary around the world, with some types being more common in certain regions and populations than others. When it comes to Rh negative blood in particular, some parts of the world have much higher rates than others.
Overview of Rh Negative Blood
Most people are Rh positive, which means they have a certain antigen (the D antigen) on the surface of their red blood cells. People who lack this antigen are considered Rh negative.
Rh negative blood types include O-, A-, B- and AB-. Those with Rh negative blood often face challenges finding compatible blood donors, as their blood can only be matched with other Rh negatives. Pregnancy complications are also more common when the mother’s blood is Rh negative and the baby’s is Rh positive.
Around 15% of the global population has Rh negative blood, but there are significant regional variations. Let’s take a closer look at which parts of the world have the largest concentrations of this rare blood type.
Highest Rh Negative Rates
Europe
Europe has the highest percentage of population with Rh negative blood compared to any other part of the world. Some parts of Europe have especially high rates:
- Ireland – 17% Rh negative
- Scotland – 15% Rh negative
- Wales – 17% Rh negative
- Basque region of France/Spain – 25-35% Rh negative (highest rate in the world)
- Rest of Europe – 11-15% Rh negative on average
The map below shows Rh negative rates across Europe, with darker shading indicating higher percentages:
As you can see, Rh negative blood is most prevalent in the western parts of Europe, especially Ireland and northern Spain.
Middle East
After Europe, the Middle East ranks second in terms of Rh negative blood frequency. Here are some statistics:
- Yemen – 12.1% Rh negative
- Turkey – 9.1% Rh negative
- Lebanon – 10.9% Rh negative
- Saudi Arabia – 6.3% Rh negative
- Jordan – 6.6% Rh negative
Yemen has one of the world’s highest rates of Rh negative blood outside of Europe. Lebanon and Turkey also have sizable Rh negative populations. However, other parts of the Middle East like Saudi Arabia have much lower rates.
Central Asia
Some parts of Central Asia, especially countries bordering Europe, also have elevated levels of Rh negative blood:
- Georgia – 14% Rh negative
- Azerbaijan – 9.8% Rh negative
- Tajikistan – 7.5% Rh negative
The percentage of Rh negatives decreases as you move further east in Asia. Still, Central Asian countries have moderately high rates compared to most other regions.
India
India is an interesting case when it comes to Rh negative blood. Overall, only 1% of India’s population is Rh negative. However, there are certain ethnic groups and castes with very high Rh negative rates:
- Kutchis – 35-45% Rh negative
- Brahmins – 24% Rh negative
- Parsees – 22% Rh negative
These three groups buck the nationwide trend and have some of the highest Rh negative rates outside of Europe. The reasons are not fully clear but may relate to isolation and ancestral bloodlines.
Africa
Rh negative blood is exceptionally rare among African populations. Most sub-Saharan African countries have Rh negative rates of less than 1%:
- Nigeria – 0.7% Rh negative
- Ethiopia – 0% Rh negative
- Somalia – 0% Rh negative
- Uganda – 0.8% Rh negative
Northern African regions have slightly higher rates, possibly due to some European ancestry. But overall, Africa has the lowest prevalence of Rh negative blood in the world.
Lowest Rh Negative Rates
We’ve looked at the parts of the world with unusually high Rh negative blood levels. Now let’s examine regions that have very low rates of this blood type.
East Asia
Most East Asian populations have low Rh negative frequencies of 0-2%:
- China – 0.5-1% Rh negative
- Japan – 1% Rh negative
- Mongolia – 1-2% Rh negative
- North Korea – 0% Rh negative
- South Korea – 0.1% Rh negative
There are essentially no Rh negatives among native East Asians. The few found are likely due to some European genetic ancestry.
Southeast Asia and Oceania
Going south into Southeast Asia and the Pacific islands, Rh negative rates remain very low:
- Indonesia – 1% Rh negative
- Philippines – 1% Rh negative
- Malaysia – 2% Rh negative
- Australia (Aborigines) – 1% Rh negative
- Papua New Guinea – 0% Rh negative
Essentially all Rh negative blood is confined to immigrant or mixed race populations in this region.
Native Americans
Indigenous groups from the Americas also have extremely low Rh negative frequencies. Rates are typically 0-1%, for example:
- Peru – 0% Rh negative
- Mexico – 1% Rh negative
- Brazil – 0% Rh negative
- Canada (Inuits) – 1% Rh negative
- United States (Apache) – 0% Rh negative
This suggests Rh negative blood was very rare or nonexistent among Native Americans before European colonization.
Theories on Origins of Rh Negative Blood
Scientists are still uncertain about exact origins of Rh negative blood. However, the uneven global distribution gives some clues. Here are leading theories on where this blood type came from:
Europe
The high rate of Rh negative blood in Europe suggests it initially arose there and spread to neighboring regions. The exact roots are unclear, but it may relate to populations that migrated west from Asia in ancient times.
Mutation Theory
Rh negative blood could represent a random mutation that cropped up relatively recently in human evolution. This would explain its scarcity around the world compared to Rh positive blood.
Separated Population
Some believe Rh negative blood signifies ancestry from an isolated population with limited genetic mixing with other groups. This could have given rise to unusual blood types not found elsewhere.
While intriguing, none of these theories provide a definitive answer. More research is needed to uncover the origins of this rare and geographically restricted blood type.
Conclusion
In summary, Rh negative blood is found at substantially higher rates in Europe compared to anywhere else globally. Within Europe, Ireland, Scotland and the Basque region have particularly high percentages. The Middle East and parts of Central Asia also have elevated Rh negative levels, likely due to European ancestry. Meanwhile, East Asia, Southeast Asia, Africa, Oceania and the Americas have very little Rh negative blood.
Understanding the regional distribution of Rh negative blood is helpful for medical purposes and sheds light on human history and migration patterns. Further research into its precise origins and emergence could reveal interesting aspects of our distant past. But for now, the isolated pockets of Rh negative blood remain something of a mystery.