Less Known Science : The curious case of Rh Negative – Part 1

Most of us know about the blood types in Humans. A little less known fact is that a total of 35 human blood group systems are now recognised by the International Society of Blood Transfusion (ISBT).
The two most important ones that a common man knows are ‘ABO’ and the RhD antigen (A, B, AB and O, with +, − or Null denoting RhD status).

Through this series,  we will look into few lesser known and “non mainstream” facets of the RhD antigen.

The Rh factor denotes the Rhesus blood factor which is a protein found in the human blood that is directly linked to the Rhesus Monkey. If your blood tests positive for this (Rh +ve), you have that factor in your blood. If you test negative, you do not have the factor in your blood (Rh –ve).

Most people, about 85%, have Rh-positive blood. That could support the idea that humans evolved from Primates and 15 % of humans have Rh-negative blood. If blood type is one of least mutable human characteristic, where did the Rh negative come from? This question has puzzled scientists for years. There are some evidences that suggests the Rh-negative blood group may have appeared about 35,000 years ago. And the appearance was regional and seemed to, originally, be connected with certain groups/tribes.

 

The Basque Connection

Data points out that Northern Spain and Southern France is where you can find some of the highest concentration of the Rh-negative factor, especially in the Basque people. The Basques have unique customs and a language –“Euskera”, that is unrelated to any other spoken in Europe, or indeed the world.  It only seemed logical to conclude that they were representatives of an older layer of population settlement, but just how far back their roots went has been a topic of debate. There are researches that show that the early Iberian farmers are the closest ancestors to present-day Basques.

Comparisons with other ancient European farmers show that agriculture was brought to Iberia by the same migrant groups that introduced it to central and northern Europe. These pioneers expanded from a homeland in the Near East, sweeping across Europe about 7,000 years ago to usher in the period known as the Neolithic.

The Caucasian Relation

Another original group with high concentration of Rh negative factor is the Eastern/Oriental Jews. In general, about 40 – 45% of Europeans have the Rh-negative group. Only about 3% of African descendent and about 1% of Asian or Native American descendent has the Rh-negative group. Due to the larger European numbers, it is a safe bet that, that was where it was introduced into the human genetic code. Could this also be where the Caucasian was introduced?? Is the introduction of Caucasian related to the RH-blood factor?

 

The Genetic Jigsaw

If the Rh-negative factor is a ‘normal’ presentation of blood, then why is there a problem when a mother of the Rh-negative blood group gives birth to an Rh-positive blood group baby?

To illustrate, a Rh-negative woman who conceives a Rh-positive child with a Rh-positive man will typically bear her first child without special problems. However, because of intermingling of fluids between mother and fetus, the first pregnancy builds up antibodies to Rh+ blood in the woman which typically attack the blood of her subsequent Rh+ children, causing them to miscarry, be stillborn, or die shortly after birth .This phenomenon is unknown elsewhere in nature, although it can occur with artificial crosses between species, as in mule production

The question is, why does the human body produce antigens to this blood type?

 

To be continued……

 


Note: All information shared is a compilation of information from multiple sources,
vetted to suit. An acknowledgement glossary will be added to the final part of the series 

 

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