Chimps belong in the Homo genus?

Humans and chimpanzees should be lumped together in the same classification—genus Homo. At least, that’s what researchers claim in a new report posted by the Proceedings of the National Academy of Sciences, USA.

The researchers base their claim on their finding that chimpanzees have more in common with humans than any other primate—allegedly sharing 99.4% of their DNA. The Associated Press (AP) then picked up the story and ran with it.

This is a breathtaking claim, especially since the trend among evolutionary scientists has been downward, from around 98.5% to 95% similarity (see Greater than 98% Chimp/human DNA similarity? Not any more.). So why the sudden shift upward?

According to the AP report, the research team, led by Morris Goodman of the Wayne State University School of Medicine (Detroit, Michigan, USA), ‘compared 97 genes from humans, chimpanzees, gorillas, orangutans, Old World monkeys, and mice.’¹ The researchers found that the genes of chimpanzees and bonobos (genus Pan) have more in common with human genes than with any other primate.

This is hardly enough data to support such a radical conclusion. The researchers compared 97 genes, but the human genome (which has only been fully mapped in a very ‘general’ sense anyway) has at least 30,000 genes—they looked at about 0.3% of the total. Moreover, the genomes of primates have not been anywhere near completely mapped. So any attempt to compare the total DNA, at present, is mostly guesswork.

Since chimps are indeed more similar to humans than other apes and monkeys, why wouldn’t this be reflected in some of their genes? It’s not surprising that similar anatomy should reflect similar genes, but that does not address the matter of the origin of the similarities, whether at the anatomic or genetic level. The question of common ancestry vs common design is not swayed one way or the other by the degree of similarity.

Even if one were an evolutionist, one would surely have to raise an eyebrow at the logic here. Say the ‘real’ overall genetic similarity between humans and chimps were 96%, for argument’s sake (even 98% would leave thousands of genes different, whereas only a handful of genes could make a crucial difference). If one decided to compare a handful of those genes only, one could get figures ranging from 0 to 100% similarity! The choice of genes inevitably has a strong subjective element.

The researchers’ argument in this case concerning how chimps should be classified focused on the relative closeness, i.e. the fact that in their study, chimps were closer to us than they were to the other great apes. But here again, a different selection of genes would conceivably easily be able to generate a different pattern in a relative sense, too. And even if not, even if this pattern were maintained, what would be the big deal? Even the crude hybridization techniques used to assess similarity to this point [see Human/chimp DNA similarity] have given the rather unsurprising conclusion that chimps are indeed genetically more similar to humans than, say, gorillas are. So whether chimps had a greater genetic similarity overall to humans than they did to gorillas (very doubtful on the basis of their morphology and comparative anatomy, as shown by the computerized morphometric techniques of evolutionist anatomist Charles Oxnard for one) would be a rather ‘ho hum’ point.

The problem is that despite being misleading, the figure of 99.4% is attention-grabbing. The general public is likely to read media reports like this as saying that chimps are ‘99.4% human.’ Even before the overall similarity was revised down to 95%, AiG was pointing out the fallacy of this logic. We quoted evolutionist Professor Steven Jones as saying that bananas share 50% of their genes with humans, but that doesn’t make bananas 50% human! So little is known about the way that genes are expressed. It is already clear that ‘not all genes are equal.’ Some genes have profound control over development, for instance. And it has long been known that the very same gene in two different creatures can have a different function. These severe limits to ‘genetic comparison’ are seldom discussed when simplistic comparisons like this are thrown around.

Using the same sort of approach as do these researchers, one could presumably show that on the basis of 97 chosen genes, humans and bananas are the very same species, since they are 100% identical!

Incidentally, even many fellow evolutionists are unconvinced by their colleague’s claims. Goodman cites a proposal in 1963 to lump chimps with gorillas based on their similarities, but he believes that the chimp-human similarities that he’s discovered are even more convincing. Anthropologist Richard J. Sherwood of the University of Wisconsin (USA) observes that Goodman is clutching at straws: ‘To go hunting for an historical reference like that and then use it as the sole criteria [sic] for suggesting a major shift in primate systematics is difficult to take seriously.’

Will Goodman’s proposal lead to any change in the primate/human taxonomy? Probably not any time soon. Goodman sounds a bit wistful in his comment to reporters: ‘If enough people get agitated by this and think it’s something to be dealt with, there may be a symposium that takes this as the central issue and determines if this is a reasonable proposal. I think it’s a reasonable proposal, of course, or I wouldn’t have proposed it.’

We asked cell biologist Dr David DeWitt, who will be speaking on Neandertal/Human DNA similarity at the upcoming Creation 2003 conference near Cincinnati, Ohio, USA, 22–26 May 2003, to comment. He wrote: ‘Classification of organisms is based on similarities and differences. It seems odd to place these three species (chimpanzee, bonobo, and human) in the same group on equal footing. A child can recognize the similarity of the chimp and bonobo as well as how different humans are from them both. This proposal could also complicate the already problematic situation with Neandertals, Australopithecines, and other alleged human ancestors. For example, evolutionary scientists do not classify the Australopithecines such as Lucy in the same genus as humans. However, this is what Goodman is proposing to do with chimpanzees.

‘It is ironic that this study pointing to chimp/human similarity appears in PNAS so close to an article that highlighted the differences between Neandertals and modern humans.² The bottom line seems to be that when evolutionary scientists look for similarities, they find similarities and when they look for differences, they find differences. Based on the number of differences in DNA base pairs, some have excluded Neandertals from contributing mtDNA to the modern human gene pool. However, based on the number of similarities, chimps and bonobos should be included in the genus Homo with man. Never mind the fact that these are arbitrary criteria.

‘Typically, in studies of this type, scientists only examine DNA substitutions, whereas insertions and deletions of nucleotides also occur. The insertions and deletions are usually left out in phylogenetic analysis because they complicate sequence alignments. In a previous paper also in PNAS, Britten included these types of DNA differences in his analysis and came up with a much lower number (~95%). Ignoring these types of DNA changes yields a much higher degree of similarity because the most common DNA change is excluded from the analysis.’

In closing: There are, and always will be, profound differences between humans, created in the image of God, and all other creatures. This is not a matter of mere assertion, but also one of observation and common sense. No chimp will be reading or discussing this report, for one thing. Our original ancestor Adam was uniquely created in the image of God with no animal forebears.

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Chimps belong in the Homo genus?

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