by Glayde Whitney
"Ethnicity can be inferred from the frequencies of alternative forms, or alleles, of genes; allele patterns differ by racial origin." Thus spake Science magazine, the official organ of the American Association for the Advancement of Science (11 Aug. 2000, p. 851).
We do indeed live in strange times. As science increasingly proves the fallacy of the egalitarian myth, politicians and politically correct scientists who want to avoid getting blackballed feed the public absurd (and wrong) banalities. For example, when it was recently announced that the human genome had been sequenced (almost), everyone including President Clinton and Prime Minister Blair got into the media spotlight. There were many statements, by such as Craig Venter {head of Celera}, that the project "proved" that races do not exist, that we are all the same under the skin. The absurdity of such egalitarian proclamations is emphasized by the realization that detailed genetic sequencing of persons from different "ethnic groups" is only now beginning.
But already, in just the last few years, it has become possible to easily categorize individuals as to race of origin by looking at their genes. This is because it turns out that there are many DNA sequences [such as STRs = Short Tandem Repeats, and SNPs = Single Nucleotide Polymorphisms] that differ absolutely between the races. Many SNPs that are common in various African tribes simply have not been found among Caucasians or East Asians, and vice-versa, Asian-specific (and Caucasian-specific) markers exist which have not been found among sub-Saharan Africans. In addition, there are markers that are found across the various races but at very different frequencies (some very common among Africans are present but very rare among Caucasians). By combining the results of a few such markers it quickly becomes probabilistically "almost" certain (one out of many millions) which race an individual is from.
On the cutting edge of genetic identification of individuals and groups is forensic genetics, DNA profiling, which will probably soon replace fingerprinting as a means of foolproof identification. In the U.S. it was only in October 1998 that the FBI started CODIS [Combined DNA Index System] in order to consolidate DNA identifications from the various State systems.
At the present time CODIS looks at only 13 STR chromosome markers, but that is enough to ensure individual identification: "The chance of two [unrelated] individuals on average having the same DNA profile is about one in a million billion."
Soon to be added will be markers on the Y-chromosome. Y-markers are interesting because the Y-chromosome is transmitted only in the male line of descent, from father to son. Already there are a number of markers on the Y that are known to be race-specific. In forensic applications Y-markers will be particularly useful because many violent crimes are male-on-female, and the resulting "bodily fluids" often consist of a messy mix of DNA from both the male perpetrator and the female victim. Analysis of Y-markers will automatically concentrate on the male DNA uncontaminated by that of the female.
Another source of DNA that is just entering forensic identification is mitochrondial DNA, called mtDNA. This stuff is interesting because it exists outside the nucleus of the cell and is passed in the egg, from mother-to-offspring. Thus all the individuals in a female line of descent will have the same mtDNA. But different families often differ, and remember, races may be thought of as extended families - sets of persons related by common descent.
MtDNA is useful because there is a lot of it: "there's probably 10,000 times as much mtDNA as there is nuclear DNA. In a sample that's aged or degraded, it's quite common that the nuclear DNA has been degraded beyond the point of recovery, and yet there is mtDNA that can be recovered."
This is why mtDNA is extracted from ancient remains, such as 100,000 year-old Neanderthals. It was mtDNA that linked the 9,000 year-old Cheddar Man to a "relative living today just down the road in Cheddar, England." It is the mtDNA that is being analyzed in an attempt to specify the racial ties of Kennewick Man.
And literally, the best is yet to come. Research at places such as the Galton Laboratory (University College London) is working on actual physical identification from DNA. "Geneticists can assess the likelihood that a person is a redhead simply by testing for mutations in the gene for the receptor for a hormone that spurs production of the pigment melanin. . All facial characteristics are on the agenda . A noble Romanesque profile or deeply cleft chin could be a villain's downfall. . within 10 years we might be looking at genetic tests for the basis of the main facial characteristics like, for example, nose, chin, and forehead shape." [Watson, A., "A new breed of high-tech detectives", Science, Vol. 289, 11 Aug. 2000, Pp.850-854].
