Large Individual Differences Seen in Human Genome
What makes each individual unique? Nature1 reported a surprising thing about “the” human genome that is becoming apparent as more individuals’ genes are examined. The first part is not surprising; the last part is:
When the finished sequence of the human genome was unveiled last year, biologists said that it told a story of harmony for the human family. Every one of us, it turns out, shares 99% of our DNA with all the other people on Earth. But it’s our differences that really fascinate us. And at last week’s annual genome meeting in Cold Spring Harbor, New York, scientists revealed a wealth of data indicating a surprising conclusion about human diversity – much of it might be explained by large structural differences between individual genomes, not by tiny differences in individual genes. (Emphasis added in all quotes.)
Some of us have more copies of a gene than others do. That’s just the beginning, Erika Check reports from the meeting: “we also have varying numbers of deletions, insertions and other major rearrangements in our genomes.”
Check claims that some of these differences are being acted on by natural selection. Europeans, for instance, have an inversion not seen in Africans or Asians that is correlated with having more children, “a classic sign that the inversion confers an evolutionary advantage”. Others at the meeting were also confident that “structural differences are important in human evolution,” and that among sections where there were differing numbers of copies of stretches of DNA, “natural selection is actively working on these genes.”
What’s more, he [Duc-Quang Nguyen, U of Oxford] found that many of these genes belong to groups that seem to help us interact with our environment. For instance, many work in the immune system, and affect how we fight off disease. These are exactly the sort of genes that could explain our diversity – why some of us get asthma when exposed to air pollution, or why some of us can eat plenty of cheeseburgers without gaining weight.
“We knew these variations existed, but this year we’re asking, do they matter?” says Ewan Birney, head of bioinformatics for the European Molecular Biology Laboratory, based in Cambridge, UK. “The answer seems to be yes.”
We’re still one human family, of course; but our DNA landscapes are a lot more varied than we had thought.
1Erika Check, “Large genomic differences explain our little quirks,” Nature 435, 252-253 (19 May 2005) | doi: 10.1038/435252b.
DNA keeps surprising us. The old picture of a relatively static library occasionally mutating to provide grist for natural selection is out. Now, we see that even among our own species – all of us being interfertile – there are remarkable differences not in just a DNA letter here or there, but in whole stretches of DNA sometimes 100 base pairs long or more. What this all means is not clear. It may be that most of our genomes cannot tolerate much divergence (see 11/26/2004 entry), but a certain fraction can vary quickly to provide robustness against changing environments and diets as people groups migrate into new areas. If so, thank God for this variability. Consider the differences in habitat between the frozen tundra, rain forest, the Sahara, grasslands, Asian steppes, forests and coastlands. The food available, air pressure, climate, insolation and biota can vary considerably. But even that explanation is simplistic; Americans go on vacation to Iceland, China and the Serengeti, don’t they? And international marriages usually produce offspring possessing “fitness,” whatever that is (see 10/29/2002 entry, “Fitness for Dummies: Is it Running in Circles?”).
Darwinists cannot claim they understand this variability any more than anyone else; that is why Check calls this a “surprising conclusion.” Thankfully, it is still politically correct for her to say, “We’re still one human family, of course.” But this knowledge through a Darwin filter could feed a new eugenics (compare 04/22/2004 and 10/12/2001 entries). When Darwinists claim that certain genes are being acted on by natural selection, some individuals are going to appear more fit than others. Certain gene patterns may be deemed unfit to reproduce. Don’t think we’ve learned our lesson and are beyond that. One only has to visualize North Korea (02/11/2005 commentary) to consider how such information could be quickly twisted for evil. “Diversity” is the politically-correct word now, but “Unity” is potentially just as potent a rallying cry for demagogues.
Associating a DNA inversion to more fecundity is unwarranted. There are many more factors than one stretch of DNA entering the picture of reproduction rates. If that were true, why are Europeans having so few kids, and worrying about their countries being overrun with foreigners? Africans and Asians seem to be overcrowding their parts of the world just fine without the inversion. The claim overlooks the many social, moral, religious, pragmatic and economic factors that go into the equation. Darwinists bluff about selection pressure and genes undergoing active selection when the picture is far too complex to draw such conclusions (see, for instance, 03/28/2005 and 01/17/2005 entries). They can’t even get one mutation in one gene to correlate well with fitness (see 02/04/2005 and 09/07/2004 entries), let alone large structural variations. Besides, the genome itself appears to be a pawn in the hands of numerous, complex epigenetic regulatory factors (see 06/03/2004 and 10/27/2004 entries). The new data about human genomic variability should remain fair game for all honest scientists, especially those outside wearing designer lab coats instead of Darwin-brand straitjackets.