May 22, 2006 | David F. Coppedge

A Challenge to our Victorian Ethics: Humans and Chimps Interbreeding

[Guest article]  Newspapers chipped away at Christian ethics last week with articles describing evidence that “early humans” bred (hybridized) with their supposed ancestors, the chimpanzees, for millions of years after becoming another species.  The New York Times reports:

David Page, a human geneticist at the Whitehead Institute in Cambridge, said the design of the new analysis was “really beautiful, with all the pieces of the puzzle laid out.”  Whether the hybridization will turn out to be the right solution remains to be seen, “but for the moment I can’t think of a better explanation,” he said.  “These crucial events in early human evolution are hard to judge dispassionately”, Dr. Page noted.  “We’d like to have a more Victorian view of our genome,” he said.  “This reminds us that we are really animals and gives us a glimpse of our past and a story that we might like to have told in a different way.

The paper by Dr. David Reich of the Broad Institute concludes that humans and chimpanzees must have interbred during the “early years” after humans supposedly branched off from the chimpanzee family tree.  He basis this on the fact that while the human and chimpanzee genetic codes found in their chromosomes all differ by a percentage, the most similarity on a percentage basis is found in the X chromosome, two of which are found in females, while the male has one X and one Y.  Since evolutionists assume that the genetic code is changing at a steady rate over time, they attempt to “date” the time when one species splits off from another by the percent differences in their genetic code and the assumed rate of change.  Dr. Reich’s abstract reads:

The genetic divergence time between two species varies substantially across the genome, conveying important information about the timing and process of speciation.  Here we develop a framework for studying this variation and apply it to about 20 million base pairs of aligned sequence from humans, chimpanzees, gorillas and more distantly related primates. Human-chimpanzee genetic divergence varies from less than 84% to more than 147% of the average, a range of more than 4 million years.  Our analysis also shows that human-chimpanzee speciation occurred less than 6.3 million years ago and probably more recently, conflicting with some interpretations of ancient fossils.  Most strikingly, chromosome X shows an extremely young genetic divergence time, close to the genome minimum along nearly its entire length.  These unexpected features would be explained if the human and chimpanzee lineages initially diverged, then later exchanged genes before separating permanently.

“Exchanging genes” of course implies these “early humans” were mating with chimpanzees, a scenario that scientists found startling, according to a report in StarNewsOnline.  Nevertheless, some are taking the theory seriously.  However, not all are convinced.  Daniel Lieberman, a professor of biological anthropology at Harvard, is quoted by the Associated Press in an article appearing in BBC News: “It’s a totally cool and extremely clever analysis.  My problem is imagining what it would be like to have a bipedal hominid and a chimpanzee viewing each other as appropriate mates, not to put it too crudely.”  (If Dr. Lieberman were consistent in his evolutionary views, the concept of “crudely” would have no meaning.)
    Others are not so easily convinced.  Science News reports that:

Anthropologist Jeffrey H. Schwartz of the University of Pittsburgh sees no merit in the new findings.  Reich’s team looked for data to support an assumption of close genetic ties between humans and chimps but skimmed over evidence of human similarities to other primates, Schwartz asserts.  The hybridization hypothesis “pushes the limits of credulity,” Schwartz says.

For a creationist response, see David DeWitt’s article on Answers in Genesis.

So what was really found in this study?  Evidence of evolution, or was evolution just assumed?  The StarNewsOnline article reports:

A principal finding is that the X chromosomes of humans and chimps appear to have diverged about 1.2 million years more recently than the other chromosomes… One explanation for this finding, Reich’s team says, is that there was a hybridization between the recently separated chimp and human lineages.

The principal finding of the study was not that the X chromosomes appear to have diverged over 1.2 million years more recently than other chromosomes.  This just assumes evolution and takes off from there.  The principal finding was that there is less percentage difference between the human and chimp X chromosomes than between other chromosomes.  That this happened because humans and chimps were hybridizing is an explanation for the difference, not a finding, and is based on the assumption of Evolution and Long Ages.  Hybridization is just speculation, however, it gets good headlines.  When you have no evidence, speculation is all you have, and there is no shortage of it.  Dr. Reich is quoted in the StarNewsOnline report:

…chimpanzee ancestors, well-adapted for living off fruit in tropical forests, seem to have been adept at spinning off variations, such as gorillas, who live on vegetation, and the human lineage, which exploited the drier woodlands that opened up between the forests… Reich said.

So now we not only know a bit about early man’s sex life, but also what they ate and where they lived.  And all this from variations in gene frequencies.  What will they come up with next?  Would you believe sexism?  Notice this astonishing claim from  “Geneticists have also found that women are biologically closer to chimpanzees than men are.  That is because the Y chromosome, which only men carry, has changed more than the X chromosome.”

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Categories: Early Man, Genetics

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