New information of Jewish descent forces a rethink:
Two remarkable studies have been announced bearing on the genomes of Jews. (Who are the Jews? Genetic Studies Spark Identity Debate, Michael Balter SCIENCE vol. 328 no. 5984 June 11, 2010 page 1342) The title strikes me as ironic, the notion that genetic studies have started an identity debate. The debate is very old. More than two thousand years ago people from Israel were taken into captivity in Babylon. After a time, many of them returned to the Holy Land. Those that did could be referred to as Jews. Soon after they arrived, some of the local people said, hello, we are members of the same people, worship the same God and wish to join with you. They were told no. So the debate goes on back that far. They were a community, and like any community decided who could properly be accepted as a member and who was not. For anyone else, that decision must stand. In fact throughout the Old Testament, the emphasis on genealogy and the reporting of the recruitment of people suggests that the debate is in effect far older.
I am reminded of other remarks that seemed ironic in historical perspective. Someone once wrote that with the release of the movie “Ghosts” people began to ask whether there was an afterlife. Of course such questions are very old. Similarly, once during the most recent war between Iran and Iraq I remarked idly to someone that I would not mind at all if they would stop killing each other. The reply was, “You have to understand, they haven’t been civilized very long.” Civilization has been in that part of the world for a very long time.
So much for the title of the article. As for the issue of who is a Jew, that remains up to the community. But a tidbit emerges that bears directly on my abiding subject. What the article indicates is that after looking at genomes it appears that the American Ashkenazi Jews, which is most American Jews, are as related as fourth or fifth cousins although about 30 % to 60 % of their DNA comes from non Jewish Europeans. There is thus a core of genetic identity that goes back thousands of years to the Middle East.
What you believe about that core I have no interest in changing, although I hope you feel good about them as I always wish everyone to feel good about everyone else. But that degree of kinship is fairly close. In fact it is so close that reasoning from the Iceland study, they should have adequate fertility.
But when I look at Wikipedia (http://en.wikipedia.org/wiki/Ashkenazi_Jews_Jews) recorded June 25, 2010, most of the 5.3 million Jews in the United States are Asheknazi. Their numbers are declining (http://en.wikipedia.org/wiki/American_Jewslkj) recorded June 25, 2010) because of intermarriage and small family size. From everything else we know, a population in the millions is far too big to be stable. One would expect falling fertility and this appears to be true.
So what is going on? Population size predicts low fertility, which appears to be present. Genome overlap predicts high fertility, which is not present. The truth must be that genome really does not matter. Fertility is not determined by genes. It must be determined by epigenetic factors. These are things that control the expression of genes.
There was already reason to suspect this. The changes in fertility with population size are just too fast for DNA mutations to be the controlling factor.
The problem is this. About a year ago I was prepared to believe that it was all genetic, or at least the knowledge of genetic overlap would provide an answer to the question, “What do I do to have adequate fertility for myself and my progeny.” In fact I was prepared to throw the last of my resources into a study that would compare genomes of couples and compare that with their fertility.
It now seems that it would never have worked. Comparing any two Ashkenazi Jews would have given the answer, “Fourth of fifth cousins.” One would have said, “Right. That’s a good match. Carry on.” This would probably have done more harm than good.
So it is a lucky good thing that I made so little progress in lining up the technology and the skilled people for such an effort. If it was a bad idea about Jews, where we knew a lot and we now know a lot more, it could have been worse for everybody else, where we know so much less.
So I really have no plan. As I say on the first page of my website, this is research and not advice. There may be a couple of rays of hope. Known family trees might help some. I suspect the number of people who know that much about their families is very small. It may be that the analysis of people’s epigenetic signals might give an answer, but that is finding a needle in an enormous haystack, and is unlikely to happen for a very long time.
Sometimes when I have explained this subject, the response has been, “Well what are you suggesting?” I haven’t had a suggestion except that the matter needs more study. And presently I am not so sure just what that study should be.
So hold on. More data will be coming. That is one thing I am confident of. Maybe there is a way through.
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