Posted on 09/02/2005 5:54:45 AM PDT by nfldgirl
By Clive Cookson, Science Editor Published: August 31 2005 18:46 | Last updated: August 31 2005 18:46
The first detailed genetic comparison between humans and chimpanzees shows that 96 per cent of the DNA sequence is identical in the two species. But there are significant differences, particularly in genes relating to sexual reproduction, brain development, immunity and the sense of smell.
An international scientific consortium publishes the genome of the chimpanzee, the animal most closely related to homo sapiens on Thursday in the journal Nature. It is the fourth mammal to have its full genome sequenced, after the mouse, rat and human being.
Some of the scientific analysis of the 3bn chemical “letters” of the chimp’s genetic code focused on its remarkable closeness to the human genome. After 6m years of separate evolution, the differences between chimp and human are just 10 times greater than those between two unrelated people and 10 times less than those between rats and mice.
But most scientists are concentrating on the differences. The vast majority of these probably have little biological significance, said Simon Fisher of the Wellcome Trust Centre for Human Genetics at Oxford: “The big challenge for the future is to pinpoint the tiny subset of differences that account for the origins of unusual human traits, such as complex language.”
The preliminary evidence suggests that the outstanding size and complexity of the human brain owes less to the evolution of new human genes than to the different way existing genes produce proteins as the human brain grows in the foetus and during infancy. Genes for transcription factors - molecules that regulate the activity of other genes and play a vital role in embryonic development - are evolving more quickly in humans than in chimps.
Three key genes involved in the human inflammatory response to disease are missing in chimps, which may explain some of the differences between the two immune systems. On the other hand humans have lost a gene for an enzyme that may protect other animals against Alzheimer’s disease. External website: Read Nature’s interactive report on the chimp genome Click here
The clearest differences to emerge from the analysis are in the Y (male) sex chromosome. While the human Y chromosome has maintained its count of 27 active gene families over 6m years, some have mutated and become inactive on its chimp counterpart.
This finding contradicts the popular view that the human Y chromosome is withering away because it has no genetic “mate” with which to swap genes - a process that repairs damaged DNA on other chromosomes. Presumably an alternative repair mechanism has evolved in humans but not in chimps.
David Page of the Whitehead Institute for Biomedical Research suggested that mating habits in the two species might explain the difference. Because male and female chimps mate with multiple partners there is stronger selective pressure on sperm-producing genes and conversely less pressure on evolution to preserve other genes on the Y chromosome in the apes than in largely monogamous humans.
I didn't think of that. While it is illegal to experiment on humans, what if some researchers altered the genome of chimpanzees to make them more human-like.
"Ye have made your way from the worm to man, and much within you is still worm. Once were ye apes, and even yet man is more of an ape than any of the apes." (Nietzsche's Zarathustra)
In other words, how the DNA is sequenced is the key to distinguishing species, not the amount of DNA. Sequencing is not explained by evolution....
Also interesting in how Y chromosome repair process varies wildly with species in the same morphological group.
How it is sequenced? What does that mean? The change described is fully compatible with evolution
In that remaining 4% their are millions of differences.
APES ARE APES AND MAN IS MAN
Still, on the other hand, water is water. And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does.
Would it be politically incorrect to inquire what percent of genes differ between human males and females?
"Frans de Waal, primate scientist at Emory University"
Uh...the title certainly fits!
Actually, the biggest differences between chimps and humans have to do with our ability to walk bipedally and also different sexual components. Also, 96% looks low to me.
The only genetic difference is that men have the Y chromosome and women don't.
The Y-chromosome, btw, is by far the smallest, containing only a few genes mainly related to sperm production and parallel parking.
We're more closely related to chimps than chimps are to gorillas and other apes (excluding bonobos of course). We are smart, hairless, bipedal apes.
I'm sure you are smart - for an ape.
I've seen the claim that in the genes it's more like 99 percent and it's when you bring in the introns and junk that it goes down to 96. Might have been on the other thread.
Not according to the article.
Nope the article does not say that
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Note: this topic is from September 2, 2005. |
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