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@rcn.com, Indian-Americans for Justice & Peace, 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.

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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).