Posted on 04/02/2005 11:48:39 AM PST by blam
Infectious Evolution: Ancient virus hit apes, not our ancestors, in the genes
March 5
Bruce Bower
A vicious virus infected ancestral chimpanzees and gorillas in Africa between 4 million and 3 million years ago. Not only did it kill a great many of these primates, but it also infiltrated the surviving animals' genomes, altering the course of evolution. That's the picture emerging from a new analysis of modern-primate DNA.
Around 1.5 million years ago, this virus of the class called retroviruses also infected ancestors of modern baboons and macaques, two African monkeys, reports geneticist Evan E. Eichler of the University of Washington in Seattle and his colleagues. However, no molecular remnants of this ancient infection appear in the DNA of people, whose ancestors also inhabited Africa, or in the genes of apes, such as orangutans, from Asia.
Retroviral infection "was almost a cataclysmic event for ancestral chimps and gorillas," Eichler says. "It's a mystery to us why the ancestors of people and orangutans were excluded from it."
While analyzing data from an ongoing project determining the chimpanzee genome, Eichler's team noticed sequences that dramatically differed from corresponding regions of human DNA. The team identified the sequences as the remains of a retrovirus.
Using chemical probes, the researchers then found more than 100 copies of the retrovirus throughout the chimp genome. These retroviral sequences disturb the workings of at least six genes, including ones found in the brain and testes.
Gorillas, baboons, and macaques also possessed about 100 retroviral copies. The researchers used available estimates of how quickly the retrovirus mutates to calculate when the infections occurred.
Several scenarios could explain the selective infection of ancient chimps and gorillas. African apes might have evolved a susceptibility to the infection, for example, or ancestors of people and Asian apes might have developed a resistance.
The new results, which the researchers report in the April PLoS Biology, fit with a surprising conclusion floated in a 2002 analysis of chimp DNA. That study found a dearth of mutations in chimp genes known to be crucial for repelling infections. Pascal Gagneux of the University of California, San Diego and his colleagues then proposed that this genomic feature was a reflection of an HIV-like retroviral epidemic among ancestral chimps nearly 3 million years ago that left only a few to pass on rare resistance genes. Today's chimps are thus the offspring of unusually virus-resistant animals.
"Retroviruses are not just diabolical [killers]," says Gagneux. "Under the right conditions, such viruses contribute to the evolution of their hosts."
Eichler's group provides "compelling evidence" of separate, comparably ancient retroviral infections in ancestral chimps and gorillas, remarks Harvard University's Maryellen Ruvolo. Chimps probably came in contact with the virus when they hunted infected monkeys, Ruvolo suggests. It's not clear how the infection reached gorillas.
The new evidence that closely related primates can contract different retroviral infections is surprising, says Dixie Mager of the University of British Columbia in Vancouver. "Most people in the field would not have predicted this finding," she adds.
Scientists have estimated that 8 percent of human DNA consists of retroviral sequences that were deposited during infections of our African-ape ancestors between 35 million and 25 million years ago.
Could be. The article mentions that macaques had the retroviral sequences, but didn't give details of whether they were Barbary (N. Africa) or the Japanese (Asian) Macaques.
If the 1.5 Mya time is correct, Homo would have had already branched off sufficiently.
On another hand, if it was introduced 4.0 Mya that makes for some interesting questions. Did Homo branch in spite of the virus, or because of it?
Darwinist propopganda.
Quite the high-rise flat.
I don't imagine that it keeps out the critters that well.
I was watching a program last night on National Geographic titled: The Ultimate Survivor and they dated these guys to 1.75 million years, Stranger In A New Land. There's a 'tip' here. Also, on the same program, they showed that the 'Hobbits' on Flores had made shell necklaces 80k years ago...which H. Erectus wasn't suppose to be smart/capable enough to do.
Great post. This might turn out to be a very important finding.
Retro virus sequences stuck in the genome sure does muddy thigs up.
Also, Replacement propaganda and "Out of Africa" propaganda.
It's not enough for the Replacement advocates, because that time frame directly impacts their claim.
A major fish kill a hundred million years before that caused fish to walk on the earth. Once upon a time ....
No mystery here...everybody knows Orangs have the best doctors....
Even if provable, the democrats and the NAACP will never permit such a thing to be suggested, let alone taught in schools.
That's another problem...how can so called "random" mutations
occur at a "regular" rate? This concept is not particularly
new. Wilson and Sarich in 1969 postulated that the molecular
genetic clocks mutated at regular rates and that allowed them
to think that they could "time" when the primates diverged
into their respective lines. But the same problem...how
does a "random" process mutate at a regular rate? Maybe
it's not random. Maybe it has no bearing on the issue.
P.S....another conundrum is ...why don't living things "back-mutate?"
Could the weather, or whatever environmental influence
is allowing the mutation to survive also reverse?...What
would that concept do to the interpretation of the fossil
record??? I assume there is no evidence for that...why not?
Let's face it, bilogically speaking, the bacteria, and viruses
, and the insects seem to be better fit for this earthly environment,
then mammals...why did they "evolve" to a more precarious
position???? Please no funny comments, like "because it's there.!"
Orangutans and human origins
Evolutionary Evidence Origin of the Theory Points of View
Dr. Jeffrey Schwartz, originator of the orangutan theory of human origins. Department of Anthropology, University of Pittsburgh. USA.
Humans have a larger number of features that are uniquely shared with orangutans than with any other living ape. Schwartz (1984) proposed that humans are more closely related to orangutans than to chimpanzees - a model that contradicts the greater genetic similarity of base pair sequences in humans and chimpanzees.
The view presented here is that genetic similarity of base pair sequences is not a necessary measure of phylogenetic relationship and that morphology continues to exist as an independently reliable source of information on evolutionary relationships. The orangutan model presents a conundrum for biological systematics over how to chose between morphological and genetic evidence when they are in conflict.
I exclude one possibility, that there has been any comprehensive comparison of nuclear DNA sequences:
"a model that contradicts the greater genetic similarity of base pair sequences in humans and chimpanzees."
The human genome projects sequenced (mostly) single samples of each chromosomes, and one of those projects used (mostly) the samples from a single individual. There hasn't been a comprehensive chimp genome project. Bands on chromosomes are somewhat similar on chimps and humans, with the chimps (and gorillas, orangutans, and gibbons) having 24 chromosome pairs.
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Human Ancestors Went Out Of Africa And Then Came Back... [1998]
ScienceDaily | Friday, August 7, 1998 | adapted from New York University materials
Posted on 12/17/2007 8:37:11 PM EST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1940963/posts
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Just updating the GGG info, not sending a general distribution.and from FR: To all -- please ping me to other topics which are appropriate for the GGG list.The Scars of Evolution:"The most remarkable aspect of Todaro's discovery emerged when he examined Homo Sapiens for the 'baboon marker'. It was not there... Todaro drew one firm conclusion. 'The ancestors of man did not develop in a geographical area where they would have been in contact with the baboon. I would argue that the data we are presenting imply a non-African origin of man millions of years ago.'" |
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Just updating the GGG info, not sending a general distribution.from the FRchives:The Scars of Evolution:"The most remarkable aspect of Todaro's discovery emerged when he examined Homo Sapiens for the 'baboon marker'. It was not there... Todaro drew one firm conclusion. 'The ancestors of man did not develop in a geographical area where they would have been in contact with the baboon. I would argue that the data we are presenting imply a non-African origin of man millions of years ago.'"
What Our Bodies Tell Us
About Human Origins
by Elaine Morgan
In re Ebola, which is reported to be devastating primate populations: IOW, are we the vector, or are they? Same question for HIV, which IIRC, does not seem to effect primates as badly as it does humans.
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