AIT, NEW genetic evidence

[Paul Kekai Manansala]

Vidyasankar Sundaresan wrote:
>
 For that,> you will have to study something inherited solely from the
father. However,> if you know biology, you will find there is no such
thing. During production> of haploid reproductive cells, there is a
phenomenon called cross-over,> where portions of DNA from complementary
chromosomes are mixed up, in order> to ensure greater genetic diversity.
In other words, the Y chromosome sperm> produced by a man is not
identical to the Y chromosome sperm that produced
> him. It carries genetic material inherited from both his father and his
> mother.

Recombination is very rare with the Y chromosome as compared to nuclear
DNA, which was the basis of earlier studies. This has been proven in
extensive clinical tests and is one reason that it is considered a
fairly reliable marker of paternal descent.

You are right on mtDNA, but a recent article in Science suggests there
is at least some male effect on mtDNA.  I'll try to dig up the citation.

With regard to mtDNA, Indians show greatest similarity to East Asian
populations and also Ethiopians. This is shown in the tables below:

Genetic Distances between Continental Populations
Group                African       Indian      Asian
 _______________________________________________________________
African
Indian               0.00440
Asian                0.00584       0.00085
European             0.658         0.00115      0.00046
_______________________________________________________________
(Bamshad et al, (1996) "mtDNA
Variation in Caste Populations," Human Biology, v. 68, 1,)



---------------------------------------------------------
Frequency of Ddel(10,394)Alul(10,397)Haplotypes in Punjab
----------------------------------------------------------
                              Haplotypes
                    ------------------------------
                     ++         +-         --
             no.     (%)        (%)        (%)
 _________________________________________________________
Caucasoids        383     1.0        21.4        77.6
Punjabi            78     26.9       12.8        60.2
Indians (Delhi)    76     48.7        2.6        48.7
Indians (A.P.)     57     73.7        1.7        24.6
Tribals (A.P.)     30     60.0        0          40.0
East Asians       153     44.4        7.2        48.4
Siberians         412     56.3       10.0        33.7
Tibetans           54     61.1        0          38.9
Sub-Sah. African  197      1.5       88.7         9.6
-----------------------------------------------------------
Source: Passarino et al., "mtDNA Polymorphisms in Northern
India,"  _American Journal of Human Genetics_, 59:927-934, Oct. 1996.

There is also a study showing similar results by Mountain et
al.(Mountain et al.,(1995) "Demographic History of India and
mtDNA-Sequence Diversity,"  American journal of human genetics,
APR 01 1995 v 56 n 4, p. 979).

A newer publication deals with mtDNA haplotype M, which was formerly
thought of as Asian origin, but which now may be connected with the
first migration out of Ethiopia, and strangely enough into India!

Quintana-Murci L, et al.
Genetic evidence of an early exit of Homo sapiens sapiens from Africa
through eastern Africa. Nat Genet. 1999 Dec;23(4):437-41.

Regarding Y chromosomes, global studies have placed South Asians in a
cluster with Southeast Asians.

The proto-European p49/TaqI haplotype 15 is not an important type in
India according to studies I have seen. There are African YAP+
haplotypes in India, but many Indian haplotypes appear to be of Indian
origin.

Regards,
Paul Kekai Manansala
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