THE EVOLUTION OF DOGS FROM WOLVES: A STORY FROM THE WASHINGTON POST:
The scientific journal Nature published an article in its recent issue dated January 23, Wednesday suggesting a hypothesis for the evolution of dogs from wolves. David Brown of the Washington Post has published a news story on that hypothesis. I contest this view as it does not take into account a principle called ‘soul and spirit’ that is the vital, animating principle found in all living creatures. The variations in genome are possible if, and only if there is an unchanging principle that could support the existence of a product generated by the genetic mutation or variation. However, the issue is not that of selective breeding of desired genetic traits. This hypothesis primarily deals with the production of a digestive enzyme called ‘AMYLASE’ and claims that this particular enzyme is a crucial factor that shaped the evolution of Wolf and its descent as Dog. Amylase enzyme produced by the digestive organ called pancreas helps the digestion of carbohydrates( starchy, plant matter) and its conversion into simple sugars like glucose that is used by cells as a fuel. Cells can utilize glucose (sugar) only with the help of a hormone called ‘INSULIN’ that is secreted by a small group of cells called the islets of Langerhans found in the pancreas. If dogs have to survive in nature eating plant matter such as starchy foods, the existence is shaped by the ability to produce Insulin hormone. Dogs by their nature are carnivores that primarily consume animal matter as food. The ability to use ‘AMYLASE’ enzyme and the use of plant matter as food is of minimal importance. However, it will be more interesting to know about the discovery of Insulin hormone by conducting experiments on dogs.
THE PROBLEM WITH THE THEORY OF EVOLUTION:
This discussion is not about God. We have to discuss what is called ‘creativity’. How do we make things that are original? I appreciate the research work that compares the DNA of dogs and wolves. We have to remember that modern man, or Homo sapiens sapiens has arrived in recent times and the paper clearly points out that agricultural activity and the development of social structures is of recent origin. It appears very easy to suggest that dogs can change their digestive abilities and increase specific enzymatic activity under the influence of a mechanism called ‘Natural Selection’ as it gives an advantage for their survival and reproductive success. How many of you have heard about the enzyme called ‘amylase’? If most of us are not sure as to which enzymes we use for our living functions, how could dogs selectively guide themselves to increase specific enzymatic activity after a short span of social interaction with human beings? The interaction between dogs and humans may have started about 11,000 years ago after the development of human societies. Kindly explain the Science, and the reasoning process applied to claim that wolves could evolve into dogs within that short span of time? Evolution is about spontaneous, random, and unguided changes in the genes, and the selection of traits that may give reproductive success and increase the ability of survival in nature. To transform a wolf into a dog is like winning the LOTTO in the first chance of purchasing the ticket. There is no natural mechanism to change the genome at one’s will and pleasure, and as per one’s convenience. Now, I can cite reports about thousands of human beings changing their diet on account of gluten(protein found in Wheat and a few other grains) sensitivity, and Lactose intolerance. The problem of food sensitivity and allergy has become a very important issue and the US policies mandate disclosure of allergen information on most of the processed food items. The problem of gluten intolerance is so severe, most consumers with gluten sensitivity only buy items that are clearly marked as “GLUTEN FREE.” The consumer demand for such gluten-free products has increased and in all US grocery stores we find hundreds of items that are sold as gluten-free. Now, we have third-party agencies which test these products and affix the gluten-free label and certify them as such. It demands that the manufacturer cannot use any kind of Wheat or gluten ingredient in the entire manufacturing facility. We fully understand the nature of this gluten sensitivity problem and there is no easy choice. Similarly, I find other people with a variety of food allergies and sensitivity issues. Kindly share that natural mechanism that evolutionary biologists call ‘Natural Selection’ and show me the way to help these thousands of people who are forced to change their diet as there is no other option.To believe in this story about Wolf to Dog evolution, kindly spare a few minutes and give me a rational explanation.
Rudra N Rebbapragada
Ann Arbor, MI 48104-4162, USA
R. Rudra Narasimham, B.Sc., M.B.B.S.,
Personal Numbers:MS-8466/MR-03277K. Rank:Lieutenant/Captain/Major.
Branch:Army Medical Corps/Short Service Regular Commission(1969-1972); Direct Permanent Commission(1973-1984).
Unit:Establishment No.22(1971-1974)/South Column,Operation Eagle(1971-1972).
Organization: Special Frontier Force.
There is no finality about these conclusions
“The findings, published Wednesday in the journal Nature, support the hypothesis that dogs evolved from wolves who found a new food source in refuse on the outskirts of human settlements. Eventually they came to tolerate human contact and were brought into the household to be guards, workers and companions.”
Learning to love grains, potatoes was key to the evolution of dogs
By David Brown, Washington Post.
Published: January 23, 2013
You know that dog biscuit shaped like a bone but made mostly of wheat? Your dog’s willingness to eat that treat, instead of going for a bone in your thigh, helps explain how its ancestors evolved from wolves into house pets.
A team of Swedish researchers compared the genomes of wolves and dogs and found that a big difference is dogs’ ability to easily digest starch. On their way from pack-hunting carnivore to fireside companion, dogs learned to desire — or at least live on — wheat, rice, barley, corn and potatoes.
As it turns out, the same thing happened to humans as they came out of the forest, invented agriculture and settled into diets rich in grains.
“I think it is a striking case of co-evolution,” said Erik Axelsson, a geneticist at Uppsala University. “The fact that we shared a similar environment in the last 10,000 years caused a similar adaptation. And the big change in the environment was the development of agriculture.”
The findings, published Wednesday in the journal Nature, support the hypothesis that dogs evolved from wolves who found a new food source in refuse on the outskirts of human settlements. Eventually they came to tolerate human contact and were brought into the household to be guards, workers and companions.
Another theory is that wolves were captured by hunter-gatherers, who tamed, bred and eventually settled down with them.
Dog evolution is a contentious subject, and the new findings are unlikely to settle the debate. Among the uncertainties is when some wolves began to evolve into dogs.
Human-tolerant — if not fully domesticated — canids may have existed as many as 33,000 years ago. Archaeological remains reveal dogs and humans sharing the same graves 11,000 years ago. That was at the dawn of agriculture; the two species appear to have been at least acquaintances by then.
“Pretty much everyone without an agenda agrees that we don’t really have a good handle about why wolves domesticated into dogs when they did,” said Adam Boyko, a geneticist at Cornell University who studies dog evolution and was not involved in the new research. “But it does seem reasonable, and in agreement with the fossil and genetic record, that it could have predated agriculture somewhat.”
The evidence of natural selection in the number and efficiency of key digestive enzymes supports the hypothesis that dogs may have domesticated themselves as a way to exploit the garbage of permanent human settlements.
“Humans had nothing to do with it,” said Raymond Coppinger, an emeritus professor of biology and expert on dog evolution at Hampshire College in Massachusetts. “There was a new niche that was all of a sudden available for somebody to move into. Dogs are selected to scavenge off people.”
Accompanying the dietary change — and probably evolving along with it — were behavior changes that allowed dogs to tolerate living near people and ultimately being adopted by them. The Swedish researchers found strong evidence of genetic differences in brain function — and particularly brain development — between wolves and dogs, which they have not yet analyzed.
In the new study, Axelsson and his colleagues examined DNA from 12 wolves and 60 dogs. The wolf samples were from animals from the United States, Sweden, Russia, Canada and several other northern countries. The dogs were from 14 breeds.
The researchers compared the DNA sequences of the wolves and the dogs (which are subspecies of the same species, Canis lupus) and identified 36 genomic regions in which there are differences that suggest they have undergone recent natural selection in dogs.
In particular, dogs show changes in genes governing three key steps in the digestion of starch. The first is the breakdown of large carbohydrate molecules into smaller pieces; the second is the chopping of those pieces into sugar molecules; the third is the absorption of those molecules in the intestine.
“It is such a strong signal that it makes us convinced that being able to digest starch efficiently was crucial to dogs. It must have been something that determined whether you were a successful dog or not,” Axelsson said.
The change is at least partly the consequence of dogs having multiple copies of a gene for amylase, an enzyme made by the pancreas that is involved in the first step of starch digestion. Wolves have two copies; dogs have four to 30.
As it happens, amylase “gene duplication” is also a feature of human evolution. Humans carry more copies of the amylase gene than their primate ancestors. People also produce the enzyme in saliva, which allows the first steps of digestion to occur while food is still in the mouth. That, in turn, rewards chewing and increases the palatability of food.
In dogs, however, the increased amylase activity occurs only in the pancreas. The enzyme isn’t at work in their mouths, probably because the food doesn’t stay there long enough. Dogs may be able to eat human food, but they still wolf it down.
The researchers found 19 genome regions containing nervous system genes that are significantly different between wolves and dogs. Eight regions contain genes governing brain development.
How those genetic mutations explain dog behavior is a topic of future research. However, the fact that so many are involved in brain maturation supports the theory that dogs are really wolves that never grew up.
Sociability around strangers, curiosity and playfulness are traits seen in both wolf pups and dog pups. So are floppy ears, broader faces and liberal tail-wagging. They all persist in adult dogs but are largely extinguished in adult wolves.
This retention of juvenile traits into adulthood — a phenomenon known as “neoteny” — is a key feature of domestication, some biologists believe. In a famous four-decade, 40-generation experiment in Russia, these traits emerged in foxes when scientists selectively bred the animals for tameness.
But the process may not require human intervention. Similar behavior probably evolved naturally in dogs. The willingness to wander fearlessly among people is a big plus if scavenging human food is your business (as it still is for millions of “village dogs” around the world).
There’s a theory that this “self-domestication” also happened in the evolution of Homo sapiens.
As people created permanent settlements — and running away from those you didn’t like (or killing them) became less of an option — there may have been a survival advantage to being cooperative and self-controlled. It’s possible that studying the genes that determine dog sociability might shed light on how a less aggressive, more civilized human evolved, Axelsson said.
It would also help explain why dog is man’s best friend. They grew up together.
A TRIBUTE TO THE SCIENTISTS WHO DISCOVERED INSULIN:
- Dogs Evolved from Wolves by Feeding on Food Waste (natureworldnews.com)
- DNA study hints availability of grains key to evolution of wolves to dogs – The Seattle Times (seattletimes.com)
- Starchy genes made dog into man’s best friend (abc.net.au)
- In Order To Live With People, Canines Evolved To Love Carbs (wnyc.org)
- How wolves evolved into man’s best friend (theweek.com)
- Carbs were key in wolves’ evolution into dogs (latimes.com)
- Increase in Availability of Grains Key to Evolution of Wolves to Dogs (mysanantonio.com)