Problems with Genetic Testing

Genetic testing is a marvel of science but there are problems with the use, (or misuse), to which some try to put it. Specifically I am referring to trying to determine ethnicity, or in the case of American Indian ancestry, trying to determine your ancestral heritage.

recently, I was arguing , or attempting to argue, (he closed comments on the post) the point with a thoroughly disagreeable person that had made some racist statements like the following.

Far from being folktales, it is genetic fact. In fact it is such genetic fact that if you take the DNA markers generally regarded as identifying a Jew, the average Palestinian is more Jewish that the average Jew.

there are two main types of testing in common use for this type of testing, mitochondrial DNA testing and Haplotype marker percentage testing of the Y chromosome.
Mitochondrial DNA, is only passed from mother to daughter and thus the fathers contribution is invisible to testing. In the same way Y marker testing can only contribute information from the male parent leaving the female parent invisible.


The genetic testing referenced used the Y marker which can only be passed by the Father and is actually 1 chromosome of the XY pair that determine whether a child will be male, (XX = female).

The Problematic Role of DNA Testing in Unraveling Human History
See here.

The problem with tying markers to ethnic identity is that Y marker testing shows only one line of ancestry. Therefore, ancestors, (females), on other lines are invisible. (The Y marker can ony be inherited from the father).

Using the Y marker a female child cannot be linked to any of her ancestors or even her mother or father. A male child can only be linked to his father, 1 in 4 of his grandparents, 1 in 8 of his great grandparents, 1 in...(geometric progression).

Using 3 generation per 100 years, in a period of 1,000 years. You have linked "1" male child to 1 of his, 536,870,912 direct ancestors using 1 of the 46 human chromosomes.

Markers mutate progressively over time, due to environmental differences, as compared to the gene used as a basis.

Logic tells us, If the supposed "base" genes are from contemporary stock grown in a different environment, the net effects are magnified. The 2 gene pools would mutate differently and at different rates. In 1,000 or 1,500 years a lot of cumulative change would occur.

essentially the study that was cited is worthless in the use to which it was put.

Haplotype percentages were used in an attempt to prove ethnicity. Haplotypes can be used for the mapping of disease genes but they do not indicate ethnicity.

To the person who said:

Far from being folktales, it is genetic fact. In fact it is such genetic fact that if you take the DNA markers generally regarded as identifying a Jew, the average Palestinian is more Jewish that the average Jew.

I don't care if some of you're best friends are Jews, you are a racist!
Where did you get that, from a skinhead manual?

While genetic Y markers "might" prove statistical relationship, they definitely do not disprove it.

Warren