Why did RH- and RH+ Evolve? Insert 1. — Louis Sheehan

I’ll do more work on this, but the following seemed interesting.  I apologize for the terrible formatting with my cutting and pasting.  — Lou

http://biology.stackexchange.com/questions/1515/origin-or-source-of-rhesus-negative-in-human-blood

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Your question has many questions in it.

As for the evolution of Rh factor, Blancher and Apoil (2000) attribute the high level of sequence similarity (92%) of the two RH locus genes, RHD and RHCE to a gene duplication event in the common ancestor of human, chimps, and gorillas. Their analysis of the cDNA from these genes revealed “complex recombination events” after the lineages split.

Basically the most recent common ancestor of apes had the “human” RH genes, which then differentiated after the lineages diverged. Duplicate and differentiate is a common theme in evolution.

As for why it’s called rhesus antigen, that’s just as experimental artifact:

The term “Rhesus antigen” was introduced by Landsteiner and Wiener, who found that rabbits (and later, guinea pigs) immunized with red blood cells (RBCs) from a rhesus monkey produced antibodies which agglutinated 85% of Caucasian blood samples (Landsteiner and Wiener 1940, 1941).

They probably weren’t even correct about the antibodies being rhesus:

In conclusion, if the term “Rh” was coined by Landsteiner and Wiener because of the source of antigens (the rhesus monkey) they used to obtain anti-Rh in rabbits, it is highly probable that, in fact, they produced anti-LW antibodies.

*****

http://www.frozenevolution.com/origin-rh-blood-group-polymorphism

The high proportion of Rh-negative persons in the European population could be connected with the fact that, until recently, big cats (the definitive host of Toxoplasma gondii) were practically not present here and thus toxoplasmosis was rare (and Rh-negative persons were at an advantage compared to the rest of the population). The low percentage of Rh-negative persons in Africa (less than 1%) could be related to the high prevalence of toxoplasmosis there, which often approaches 100%.

*****

http://www.sott.net/article/228188-Toxoplasma-gondii-Cat-parasite-may-affect-cultural-traits-in-human-populations

Lafferty suggested that because climate affects the persistence of infectious states of Toxoplasma in the environment, it helps drive the geographic variation in the parasite’s prevalence by increasing exposure risk. The parasite’s eggs can live longer in humid, low-altitude regions, especially at mid latitudes that have infrequent freezing and thawing. Cultural practices of food preparation such as rare or undercooked meats, or poor hygiene, can increase exposure to infection, as can having cats as pets. Lafferty added, “Toxoplasmosis is one of many factors that may influence personality and culture, which may also include the effects of other infectious diseases, genetics, environment and history. Efforts to control this infectious pathogen could bring about cultural changes.” / this is why I feel rh- is a newer blood grouping due to the last ice age conditions. these were the conditions in nw Europe back then and the rh- trait has persisted in that area. it just all makes sense . you may also search out ” congenital toxoplasmosis infection ” and I believe you will find when a pregnant woman gets toxo infection the baby comes out with the same symptom ology as erythroblastosis fetalis, rhesus disease.this is why all pregnant women are cautioned to avoid cat feces and stay away from cat boxes where they defecate.

OPINION ? i’ll have you know i’m 61 y old retired medical worker who has studied biology and etc my whole life . this opinion is not just anyone’s . btw i’m o- myself

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http://www.ncbi.nlm.nih.gov/pubmed/18766148

RESULTS:

RhD-positive subjects have been confirmed to be less sensitive to the influence of latent toxoplasmosis on reaction times than Rh-negative subjects. While a protective role of RhD positivity has been demonstrated previously in four populations of men, the present study has shown a similar effect in 226 female students. Our results have also shown that the concentration of testosterone in saliva strongly influences (reduces) reaction times (especially in men) and therefore, this factor should be controlled in future reaction times studies.

CONCLUSIONS:

The observed effects of RhD phenotype could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), differences in the RhD+ allele frequencies in geographically distinct populations (resulting from geographic variation in the prevalence of Toxoplasma gondii), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

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The observed effects of RhD phenotype could provide not only a clue to the long-standing evolutionary enigma of the origin of RhD polymorphism in humans (the effect of balancing selection), differences in the RhD+ allele frequencies in geographically distinct populations (resulting from geographic variation in the prevalence of Toxoplasma gondii), but might also be the missing piece in the puzzle of the physiological function of the RhD molecule.

Again, the link:
http://biology.stackexchange.com/questions/1515/origin-or-source-of-rhesus-negative-in-human-blood

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About masterkan

Louis Sheehan
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