Ok.
Another photo of domestic cat who's had its genes messed with:
Posted on 07/18/2006 9:06:26 AM PDT by PatrickHenry
Thanks to their domestication and favored pet status, dogs have enjoyed a genetic variability known to few other species.
It may be time to revise that old maxim about humans and their canine companions. A man, it seems, is a dog's best friend, and not vice versa.
A paper in the June 29th issue of Genome Research presents evidence suggesting that the domestication of dogs by humans has given rise to the immense diversity of the canine species by allowing otherwise harmful genetic mutations to survive.
"Dogs that would have otherwise died in the wild would have survived because humans would have allowed them to," said Matt Webster, a geneticist at the University of Dublin and one of the study's authors.
The stunning diversity of dogs — Canis lupus familiaris, includes lumbering St. Bernards, sprightly Jack Russell terriers, and graceful greyhounds — has been a source of scientific interest since Darwin, who speculated that these creatures must have descended from several different species. (Scientists now know dogs have a single ancestral species, the gray wolf.)
"Within a single species you have this tremendous range of morphological variation, all this diversity — head shape, body shape, coat color, length — and a tremendous amount of variation in behavior," said Leonid Kruglyak, a geneticist at Princeton University. "Where does all this come from? The parent species, which is the wolf, doesn't show this diversity."
Webster and his colleagues collected and sequenced DNA from the mitochondria of wolf and dog cells. Using this data, they looked for genetic mutations and calculated the rate at which mutations appeared.
Genetic mutations can be divided into two broad categories: nonsynonymous mutations actually change the protein that a stretch of DNA codes for, while synonymous, or silent, mutations do not.
Webster and his colleagues found that the silent mutations occur at similar rates in dogs and wolves, but that nonsynonymous mutations accumulate twice as fast in dogs as they do in wolves. These random changes to proteins are usually harmful, and would have a weakly deleterious effect on dogs and their ability to survive, said Webster.
"That suggests that during dog evolution there's been a relaxation of selective constraint," he said. "These additional changes that have happened during dog evolution have escaped the pressure of natural selection."
Because humans made it easier for domesticated dogs to survive, random genetic mutations that reduced evolutionary fitness — and would have died out in wild dog populations — were able to persist. Furthermore, as humans bred dogs for more desirable traits, they may have exploited these random mutations, accentuating already present variation.
"A lot of the changes over dog evolution would have provided the raw material that humans have used to shape different breeds," Webster said.
The result, then, is the phenomenal diversity in characteristics among different dogs and dog breeds today.
Elaine Ostrander, a geneticist at the National Human Genome Research Institute who worked on the institute's dog genome project, praised Webster's research and its use of mitochondrial DNA.
"For them to focus on mitochondrial DNA was an insightful decision," Ostrander said. "It's been neglected in canine genetics."
Mitochondrial DNA, because it resides outside the cell nucleus, is passed down only from mother to offspring, and it accrues mutations particularly fast. While that might make mitochondrial DNA a natural place to study rates of genetic variation, it's not yet clear whether Webster's findings will apply to the nuclear genome.
"The mitochondrial genome is such a small percentage of the dog genome," said Princeton's Kruglyak. "The interpretations are somewhat speculative."
Nevertheless, he conceded that the researchers' findings and proposed explanation are reasonable, even if not definitive.
"It's difficult to figure out what exactly happened over the last 10,000 years of dog domestication," he said. "It's not clear that any other species has been pushed by artificial human selection to the same extent. There's definitely a very interesting set of questions to be answered."
Well, I don't disagree with you, nor do I disagree with you that there is a fundamental distinction between the human/dog symbiosis (i.e., domestication & selective breeding) and other types of symbiosis, but nonetheless human intelligence and human industry are natural phenomena. I am not saying that there aren't 'artificial' products of human behavior; what I'm saying is that human artifice is natural.
Your Hitler quote is obviously inauthentic. They didn't have "reset" buttons on computers back then.
Seriously, I'm not aware of much evidence for what you suggest. BTW, humans aren't "remarkably similar" (compared to the average large mammal). It's easy to argue that they are highly variable. What you may mean to say is that this variation is not sorted out into distinct races or subspecies to the extent it tends to be in other species.
This has been happening since the dawn of time but the pace has picked up over the past century. Every time we overcome a genetic trait that impedes survival or reproductive success the result is that the trait becomes more prevalent. Just two examples: The invention of eyeglasses led to an increase in nearsightedness as the almost-blind prospered, and the discovery of insulin caused diabetes to spike as diabetics could survive long enough to have children of their own. I think we'll see a similar rise in cystic fibrosis; when I was a kid the life expectancy of a CF patient was about 15 years but now it's not uncommon for them to make it past 25.
The Flood was a big reset button. Worked well, didn't it?
You didn't. What I objected to in the article is the false dichotomy between human endeavor and the natural world that is ultimately an importation from subjective metaphysics.
LOL. That's the hand!
The gray wolf? That's a North American wolf-surely an Old World wolf-the European brown, or the Indian wolf-is the ancestor of the dog (except for native American breeds, maybe).
I wish that it was true. One of the great rewards of Heaven for me would be reunion with my beloved pets. On the other hand, my wife had a destructive mutt that ought to burn in Hell.
It's bothered me as well. Sentinence & emotional capacity appear to be as much as a continuum as variation of species.
In fact, I know a lot of humans who are heckvua lot more immature than animals.
Dingos are dogs and no they didn't, at least not successfully enough to show up in the DNA.
Actually, it's a poorly written story about selective breeding with an even more poorly written headline. (I would have preferred cutsy pics of dogs myself)
Invalid analogy. Humans are observed to exist. "Intelligent designers" as postulated by ID advocates are not.
Ok.
Another photo of domestic cat who's had its genes messed with:
The incidence of nearsightedness varies of the degree of literacy ~ with the effort required to read resulting in a lengthening of the eyball.
Since most Type I diabetics back in the "good old days" survived long enough to pass on their genes, the invention of artifical sources of insulin has not had any impact. Type II diabetics are usually not discovered until past mid-prime by which time they've already passed on their genes. Besides, additional insulin doesn't help them at all.
Best bet on culturally induced genetic change in humans has been the effect of shoes/sandals on the foot.
It's pretty obvious our two smallest twos (and associated bones) have been becoming smaller over several tens of thousands of years since we first started using shoes/sandals (and moving "North").
Otherwise, that's about it~
It's closer to a Darwin quote than a Hitler one. In Darwin's Descent of Man he explains the role of warfare in human evolution. Schools embrace Darwin's ideas on natural selection but ignore Darwin's book on human evolution, especially the key role tribal warfare plays in it.
Humans are the most genetically complex animal ever. Obviously something much faster than natural selection was going on. That something is our war making disposition. It's very important to understand the true nature of man, as leftist beliefs may have you exiting the gene pool.
In the animal world there are many variations on a theme, such as birds and fish. In humanoids there is only one species still alive. That's because we killed off in war all similar competitors long ago, the Neanderthals being the last. There are very little variations of a theme in modern humans, we are all remarkably the same. War is the reason behind this.
(--Must have also bred larger brains into them as well...they don't believe they are dogs, and act quite human--actually preferring a conversation in full sentences to the normally blunt one or two word commands ;----)
"I don't know if the diversity of dogs represents evolution or selective breeding from man,"
Same thing, really.
Selective breeding is basically artificial evolution.
Those traits that favor the environment created by man get to breed. Those that do not, not so much.
I think barking in the middle of the night is what early man found most valuable about dogs, that, and eating garbage.
Barking in the middle of the night saves the master's life when the intruder is dangerous.
Eating garbage prevents diseases from getting started or spreading.
It would be very hard to breed these traits out.
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