A miracle of
evolution!
Scientists say chimps are closer to human than other apes
Published on Darwin Day (February 12, 2006)
We are about to celebrate the International Darwin Day on February 12, 2006. I was wondering what I should write to commemorate Charles Darwin on that auspicious day. Then I read a news item recently through which I learned that genomics study had led to the conclusion that chimpanzees are more closer to human than other great apes. This finding is bolstering Darwin's theory of evolution. I get a Goosebumps when I think that about 150 years or so ago Charles Darwin had the fortitude to publish his seminal work on evolution. The world of science has universally accepted Darwin's theory a long time ago. Now, the burgeoning fields of genomics, proteomics, etc., are putting the last nail in the coffin so to speak. The more we learn about genomic content of chimpanzees, the more we appreciate that chimps are closer to us than it was presumed to be by biologists.
It is a small wonder that not only Chimps are intelligent enough to use basic tools, they have rudimentary language (as per linguists). Knowing that chimps could be funny they have been used in TV commercials, but now researchers in genomics have ample proof that they are more closely related to humans than other great apes. Genetic tests comparing DNA from humans, chimps, gorillas, and orangutans indicate striking similarities in the way chimps and humans had evolve, which set them apart from the others.
The new finding gives credence to a controversial proposal to scrap the long-used chimp genus "Pan" and reclassify the animals as members of the human family. If this suggestion is accepted then it would give chimps a new place in "creation's pecking order" alongside humans, as one newspaper reporter added in his piece in England in late January 2006. Thus, chimps would be the only survivor of the genus Homo. How wonderful!
A team led by Prof. Soojin Yi, a professor of Ecology and Evolution at Georgia Institute of Technology in Atlanta, compared 63million base pairs of DNA from different species, where each base is a letter in the animal's genetic code had analyzed the DNA to look at what evolutionary biologists call the molecular clock, the rate at which an animal's genetic code evolves through mutation. The speed of the clock then shows how the span of a generation has changed over the millennia. My second son, Riaz, is now taking biology in his freshman year at the same university. He tells me that the professor teaches evolution and ecology at the school. I strongly recommended him to take courses in evolution from the famous teacher.
The tests Prof. Soojin's team did show that even though humans and chimps split from a common ancestor between 5 million and 7 million years ago, the rate at which their genetic codes were evolving was extremely similar, differing surprisingly by only 3%, and much slower than gorillas, and orangutans. A slow molecular clock indicates that the time between generations is long, something that has historically set humans apart from the great apes. Prof. Yi's team member Navin Elango said: "We found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes." The Georgia Tech scientists have published their genomics work in the Proceedings of the National Academy of Sciences, a prestigious scientific journal published in the U.S. Their finding suggests some human traits only emerged 1 million years ago, a fleeting moment on evolutionary scales, though.
Prof. Yi told the newspaper reporters that their study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than in two different genuses. The basis for such assertion comes from the fact that we humans not only share extremely similar genomes, but also we share similar generation time (as per molecular clock).
The taxonomy of chimpanzee and theirs position in the evolutionary tree have been a matter of contention from the very beginning. In 1775, when scientists first named the chimpanzee, they noted the similarity with people and placed them next to humans under the genus Homo.
However, by 1816 chimps had been pushed out into their own genus, Pan, which has survived up until now. I learned from a recently written article on chimps that In 1991, the Pulitzer prize-winning ecologist Jared Diamond dubbed humans �the third chimpanzee,� setting us alongside the common chimp (Pan troglodytes) and its less aggressive but astoundingly promiscuous cousin, the bonobo (Pan paniscus). The controversy over chimps� close relationship to humans prompted scientists in New Zealand to join forces with lawyers to petition the country's government to pass a bill conferring "rights" on chimpanzees and other primates. The move however was ridiculed. New Zealand�s self-appointed moral philosopher Roger Scruton, asked: �Do we really think that the jails of New Zealand should henceforth be filled with malicious chimpanzees? If not, by what right are they to be exempted from punishment?� After much deliberation, New Zealand granted great apes legal protection from animal experimentation. In England, British Home Office guidelines also prevent experiments on chimps, gorillas, and orangutans.
Researchers at Wayne State University in Detroit re-ignited the debate in 2003 when they found that 99.4% of the most critical DNA sites are identical in human and chimp genes, prompting one researcher, to declare that chimps and humans should be grouped together under the same genus, Homo. The Oxford University's evolutionary biologist, Andrew Rambaut, had opined that chimps and humans are really not that different to each other. The professor thinks that reclassification of chimps �could raise the chimp's profile and potentially improve their conservation.� Prof. Rambaut humorously said, �It seems a bit human-centric to want to put chimps into the �Homo� genus and not reclassify humans as �Pan.� But these things are arbitrary, once you've divided it into species. It would become a more political decision than anything else.�
The new finding that chimps are more closer to humans should ring alarm bell to religionists allover the world. The practitioners of monotheistic religions (Jews, Christians, and Muslims) think God created human in His own image about 5-6K years ago. However, molecular clock puts the time when early members of genus Homo separated from other related apes at 1 million years ago. Try telling a fundamentalist Christian or a Jew or even a Muslim the scientific fact about human evolution and see how they respond. However, the answer should not ruffle feathers among folks who trust Darwin's theory of evolution.
Interestingly, in Darwin's time no one knew what a gene was never mind genomics. However, in a short span of time (150 years in evolutionary time scale is a blip, literally) DNA was discovred, its structure elucidated, which gave birth to a slue of scientific disciplines. These new fields are putting the last nail in the coffin of Biblical account of the creation of Adam and Eve. How long will it be before a majority of earth�s population would say sayonara to folklore of the Genesis and embrace Darwin's view of how humankind had evolved? We should wait for that day in our lifetime and celebrate it with due �lan and �clat to remember one more time the great findings of Charles Robert Darwin.
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Dr. A.H. Jaffor Ullah, an enzyme researcher and columnist, pens this essay from the campus town of Cornell in Ithaca, NY.
