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January 24, 2005
Ethnic Genetic Interests - Part 2
In the previous post I outlined the concept of ethnic genetic interests, as advocated by Frank Salter, and offered some general philosophical objections to it. Here are some more technical comments:
1. Salter frequently talks about the ‘distinctive genes’ of an ethnic group or race, but very few alleles are confined to a single race. More often, all races share all alleles, but at moderately different frequencies. Typically, in a two-allele system there is a difference of 30 or 40 percent in frequency of an allele between continental races: for example in ratios such as 40:80, 50:85, or 65:95. (The differences may be somewhat greater for Y chromosome or mtDNA haplogroups, where transmission is only through one sex, and there is no recombination.) These differences in frequency are sufficient to generate the levels of genetic distance (as measured by FST) found between such populations, which are usually in the range of .1 - .2. For example, a frequency for a given allele of 50% in one population and 85% in another would produce an FST of about .14 between them, which is larger than the FST between white Europeans and Australian aboriginals (Salter, table on p.68). In promoting their ’ethnic genetic interests’, in opposition to other populations, ethnic groups would therefore not be preserving unique alleles, but merely bringing the global frequency of these alleles closer to the frequency found in their own group: neither more nor less. (If all other ethnic groups in the world were exterminated - which even Salter might consider a bit extreme - this goal would be exactly achieved.) Why anyone should consider this a ‘vital’, ‘fundamental‘, or ‘ultimate’ interest is beyond me. Why so much fuss about shifting a gene frequency from, say, 50 percent to 60 percent? I am not sure that Salter himself is aware of the rather footling nature of his ‘ultimate interests’, once one strips away the rhetoric. (It might be said that the important thing about population differences is the scope for distinctive gene combinations, but Salter himself doesn’t pursue this line, so I won’t linger over it.)
2. It is also doubtful whether the frequency of alleles, and the resulting measure of ethnic genetic kinship, is the most appropriate way of measuring genetic similarity and difference within Salter’s own conceptual scheme. After all, what is an allele? Any difference between two DNA sequences, however small - as small as a single base substitution - is sufficient to constitute them as different alleles, regardless of any effects on their functions or fitness. This may be appropriate for tracing ancestry and reconstructing phylogenies - the main purpose for which these frequency differences are used - but it does not seem especially relevant for Salter’s stated ‘ultimate interest’ of ‘genetic continuity’. For this purpose a more natural measure would be the extent of similarity between genetic sequences as a whole, measured by the proportion of identical DNA. But if we adopt this measure, ’ethnic’ differences become trivial: between human continental races genetic sequences differ by only about a tenth of 1 percent of all DNA bases. Please note that I am not falling into ’Washburn’s Fallacy’. The question is what is the appropriate measure of genetic difference for Salter’s avowed aim of preserving ’genetic continuity’, and for this purpose the proportion of identical DNA is more logical than the proportion of identical alleles. If our concern is simply to maximise the amount of identical genetic material to our own that is transmitted to future generations, it makes hardly any difference whether this is done by our own ethnic group or another one. It is far more important to maximise the amount of human reproduction in general. Of course, I don’t suggest that this is desirable: in my view quality is more important than quantity. But for Salter quantity is apparently everything.
3. Salter repeatedly describes the pursuit of ethnic genetic interests as ’adaptive’, but his use of this term is unusual. An adaptive gene is usually regarded as one which in some way enhances organism function or reproductive fitness. Such genes are favoured by natural selection, and may be contrasted with those that are selectively neutral or counter-selected. But this is not what Salter means by adaptiveness. For Salter, it is by definition adaptive for an individual to maximise the number of copies of his own genetic material, regardless of its selective value. So, for example, it is adaptive for an individual with Huntingdon’s disease to maximise the number of other Huntingdon’s sufferers. Needless to say, this is not an example Salter gives himself, but it is a consequence of his principles!
4. To a large extent the genetic differences between populations are due to random processes such as founder effect and genetic drift. Many population differences in allele frequency are selectively neutral. However, Salter explicitly rejects any attempt to distinguish between neutral and non-neutral differences: they are all equally part of an individual’s ’genetic interest’. This seems absurd. Salter anticipates this objection, and replies that ’random processes are fundamental to evolution and are even built into the way we produce our children [through the process of meiosis and sexual reproduction]… If the random element in ethno-genesis is a reason to doubt the value of ethnic kin, it must also be a reason to devalue one’s offspring as a store of genetic interests‘ (p.96). A debating answer to the last point would be that meiosis does reduce the value of our offspring to us by a half, as compared with clonal offspring, which is why there is a notorious problem of explaining sexual reproduction! But in any case the real objection is not to the random origin of the differences between populations, but to their lack of adaptive value (in the usual sense of ’adaptive’). Salter fails to explain why non-adaptive genetic differences should be of ‘interest’ to anyone. To give an analogy, if a painter wishes to make a good copy (as distinct from a forgery) of a famous painting, he will not try to replicate all the cracks, discolorations, and dirt that have come to blemish its surface over the years. These are not what give the picture its value. But for Salter every genetic blemish is sacred.
5. Of course, some differences between populations must have been adaptive (in the usual sense) at some time. But this is no guarantee that they are still adaptive in modern conditions. Salter’s theory implies, for example, that African populations who have migrated to temperate countries should seek to preserve their ’distinctive’ African genes - even those, like the genes responsible for sickle-cell anemia, which are actively harmful in their new environment. As I emphasised in my previous post, Salter’s position is essentially backward-looking and anti-eugenic.