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DNA, Genetics & Population Dynamics: Debunking the Aryan Invasion

Propaganda Chandrakant

Pansé, Professor of Biotechnology

Summary: The stark lack of similarities in the gene pools of India and

Europe, vividly evident in mitochondrial DNA and the MHC complex, destroys

any >Aryan invasion= notions; on the other hand, the genetic uniformity of

people of North and South India has been confirmed.

 

Background

 

Study of changes (mutations, insertions) in chromosomal DNA is very

difficult due to its magnitude. In humans, the egg contains 22 chromosomes

plus the X sex chromosome, and the sperm has similar 22 plus either the X or

the Y sex chromosome. An XX combination in the embryo ensues a female, and

an XY a male. There are some 3 billion DNA base pairs in the 46 chromosomes

in a human cell. Studying changes as markers in only the Y chromosome can be

simpler, but traces only the male ancestry.

 

Cells contain mitochondria, structures where oxygen is utilized. A

mitochondrion has its own DNA, only 16,569 base pairs long, and entirely

independent of the chromosomal DNA. Following mutations in the mtDNA is thus

significantly easier, but traces only female ancestry as the mitochondria

are descendants of the egg, with no contribution from the sperm.

 

Attempts at linking of populations through insertions of repeat sequences

are underway (1), but call for abundant caution because sampling errors,

numbers of markers employed, choices of markers, statistical models selected

for analysis, etc., influence the results of such studies (2). More

importantly, polymorphism (different alleles, or slightly different forms of

the same gene) subjected to local positive selection can result in

convergent evolution, the reverse also holds true, and these can lead to

abnormal conclusions regarding histories of populations (2). Attempts to

demonstrate similarities amongst Asian and European gene pools not only

suffer from such drawbacks in spite of vigorous statistical analysis, but

also can be explained by multiple mechanisms (3).

 

North & South Indians Share mtDNA, Which Is Distinct From That of Europeans

 

Extensive sequencing and statistical analysis of a part of mtDNA which has

sustained mutations (the mitochondrial hypervariable region I, HVR I), from

reasonable sample sizes, has shown that certain sequences dominant in Europe

are uncommon in India, and when found, are almost equally divided amongst

the North and South Indians; conversely, there are sequences common to both

the North and South Indians which are uncommon in Europe (4). These data

have been used to estimate the time of diversion of the peoples of Europe

and Asia in the Pleistocenic era (4), emphasizing that these are

phylogenically different peoples (5).

 

North & South Indians Share Tissue Antigens, Distinct From Those of

Europeans

 

All diploid human cells express a set of proteins on their surfaces, HLA-A,

B and C, which can be unique to an individual. They are coded for in the

major histocompatibility complex of genes (MHC class I) on chromosome 6.

These are the proteins which are recognized as non-self by the immune system

in transplant rejection, and are variously called transplant antigens,

phynotypic markers, cell-surface markers, etc. All of these proteins in all

persons have identical structures and functions, yet can be distinguished

from others. Not all 6 class I antigens (3 each from paternal and maternal

copies of chromosomes 6) may be unique to an individual. MHC class II

proteins (DP, DQ, DR), required for raising immune responses, are mostly

expressed by some immune system cells only, but may be even more diverse

(polymorphic).

 

Analysis of the DNA sequences coding for the different forms of these

proteins (alleles) demonstrate that while populations which are closely

related, geographically or through known migrations, show similarities in

their class I and II MHC antigens, the Asians and the Europeans are distinct

peoples with distinct sets of MHC antigens (6).

 

Conclusion

 

The so-called Aryan invasion, an idea designed to divide the Hindus of

Northern and Southern India, was never supported by any concrete evidence

and yet was elevated to the stature of a theory. It has been pushed in

secondary school textbooks as a dogma. Science now conclusively rejects any

notion of any Aryan invasion of the Indian subcontinent.

 

 

Chandrakant Pansé, Professor of Biotechnology

Newton, Massachusetts, DrCP, Indian-Americans for Justice & Peace,

www.iajp.org <http://www.iajp.org>

 

Credits

I gratefully acknowledge research support from Dr. Ujwala Pansé, professor

of biochemistry, and our daughter Kumari Anjali Pansé.

 

References

 

1. Callinana PA, Hedgesa DJ, Salema A-H, Xinga J, Walkera JA, Garbera RK,

Watkinsc WS, Bamshad MJ, et al. Comprehensive analysis of Alu associated

diversity on the human sex chromosomes. Gene 317, 103 110 (2003).

 

2. Bamshad M, Wooding S, Salisbury BA, Stephens JC. Deconstructing the

Relationship Between Genetics and Race. Nature Rev. Gen. 5, 598 609 (2004).

 

3. Watkins WS, Rogers AR, Ostler CT, Wooding S, Bamshad MJ, Brassington AE,

Carroll ML, Nguyen SV, Walker JA, Ravi Prasad BV, et al. Genetic Variation

Among World Populations: Inferences From 100 Alu Insertion Polymorphisms.

Genome Res. 13, 1607 1618 (2003).

http://www.genome.org/cgi/content/full/13/7/1607.

 

4. Kivisild T, Bamshad MJ, Kaldma K, Metspalu M, Metspalu E, Reidla M, Laos

S, Parik J, Watkins WS, Dixon ME, Papiha SS, Mastana SS, Mir MR, Ferak V,

Villems R. Deep common ancestry of indian and western Eurasian mitochondrial

DNA lineages. Current Biol. 9, 1331 4 (1999).

 

5. Disotell TR. Human evolution: the southern route to Asia. Curr. Biol. 9,

R925 8 (1999).

 

6. Arnaiz Villena A, Karin M, Bendikuze N, Gomez Casado E, Moscoso J,

Silvera C, Oguz FS, Diler AS, de Pacho A, Allende L, Guillen J, Laso JM. HLA

alleles and haplotypes in the Turkish population: relatedness to Kurds,

Armenians and other Mediterraneans. Tissue Antigens 57, 308-317 (2001).