Wow! That was impressive Corto Maltese. How brave and heroic the dog was. And I was relieved to learn the other dog survived. Thanks for sharing that.
That is definitely what I see being done with Shelties in France where they "prefer" the British standard dog and don't care for the North American dogs which are more robust and much less inbred. I just got a copy of the latest sheltie club magazine and the dogs that win prizes in France I wouldn't want to own. I was unable to get my Canadian/U.S. registered dog "confirmed" as pedigreed in France because he is one centimeter too tall! They want to breed them down to miniature sizes and that brings us to some of the problems that show up in genetics research relating to domestication.Corto Maltese said:For those considering pure breed dogs have a look at this
pedigree dogs exposed by bcc:
I wish that BBC piece on purebred dogs was subtitled in French - I'd send it to the Sheltie club people.My little zebra: The secrets of domestication
In 2003, while geneticist Svante Pääbo was visiting Novosibirsk, Russia's third-largest city, he decided to look in on a famous experiment run by the Institute of Cytology and Genetics, which is based in the city. Fifty years ago, the then head of the IC&G, geneticist Dmitry Belyaev, had begun breeding silver foxes to see how easily they could be tamed. What Pääbo didn't know, though, is that Belyaev had also set up another experiment in the 1970s involving rats. This time, one line of rats was selected for tameness and another selected for aggression.
When Pääbo saw them, he was stunned. After just 30 years of selection, the IC&G researchers had fashioned two populations that could hardly be more different. "I could take the tame ones out of the cage with my bare hands. They would creep under my shirt and seemed to actually seek and enjoy contact," recalls Pääbo. "The aggressive animals were so aggressive I got the feeling that 10 or 20 of them would probably kill me if they got out of the cages."
Here was a great opportunity to uncover the genetic changes responsible for the behavioural differences, Pääbo realised. Back at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Pääbo and his team have been trying to do just this. If they succeed, their findings could have far-reaching consequences.
The zebra, for instance, is a stubborn beast, one that has thwarted all efforts to domesticate it, as have the cheetah, the African buffalo and the rhinoceros. Understanding the genetic basis of tameness might make it possible to domesticate the undomesticatable and turn exotic species into farm animals or even pets. It could also help us understand what makes some people overly aggressive - and perhaps even lead to treatments for behavioural disorders.
Most domesticated mammals are really rather different from their wild ancestors: they often have a radically different body shape, frequently sport unusual fur patterns or markings, and it is not uncommon for them to be able to breed all year round. Surely it must have taken many, many generations for all these differences to accumulate?
Charles Darwin certainly thought so, suggesting the process of domestication was "insensibly slow". But Belyaev thought otherwise. He proposed that many of the features typical of domesticates arose because our distant human ancestors made their initial selection of wild animals on the basis of just one, rather practical characteristic: tameness. If this were the case, domestication was not only simple, it might also have taken far fewer generations than imagined.
A simple thought experiment will give an idea of how Belyaev probably saw things. Imagine yourself back some 10,000 years. You've been hunting and gathering for as long as you can remember, and quite frankly you're sick of it. There, on the horizon, is a herd of herbivores. Wouldn't it be nice, you think, if you could keep and breed a few close to home? You'd have ready access to meat and milk all year round. Life would be so much easier.
You slowly approach the herd. The skittish animals stamp and back off. The unflustered ones blink and stay their ground. The upshot is that the animals you end up taking home are the ones that are least perturbed by human company. If this behavioural trait has a genetic basis, you have already selected animals boasting genes for tameness. That, the bold Russian hypothesised, is a crucial step in domestication. All the other stuff that characterises most domesticated mammals - the floppy ears, varied coat markings and altered reproduction - are simply by-products of selecting for tameness.
In 1959, Belyaev set out to test his idea. He obtained 130 relatively friendly silver foxes from a fur farm in Estonia and installed them at a farm near the small town of Kainskaya Zaimka, on the outskirts of Novosibirsk. He began to breed them, but in each generation only allowed the very tamest animals to reproduce. Within four generations, some of the foxes had started to wag their tails; after eight generations new spots and markings began to appear on some of the offspring; then ears flopped, tails shortened, skulls widened and the foxes became more relaxed about when they bred. After just 20 years, Belyaev's team had created a domestic fox.
Further investigations into the animals' physiology were revealing. Compared with wild silver foxes, the tame foxes have reduced activity of the hypothalamic-pituitary-adrenal axis, a complex set of nervous and hormonal signals that, among other things, controls an animal's response to stress. Tame foxes also have higher levels in their brains of serotonin, a neurotransmitter that inhibits aggressive behaviour. These and other subtle modifications go some way to explaining why the tame foxes are so chilled-out.
The silver fox is just one animal, though. Would selection for tameness bring about similar rapid changes in other mammals, too? It was to address this that Belyaev obtained a group of wild rats in 1972 and set about creating the two lineages.
Next, Belyaev turned his attention to American mink. He approached a fur farm housing 30,000 animals and came away with 200 relatively tame individuals. After just four generations of selective breeding, there was clear evidence that domestication was under way. Not only were the animals easier to approach, but novel coat colours and other anatomical features had started to appear, just as they had done with the foxes.
Starting in 1980, the researchers began to capture wild river otters, bringing them to the farm from Sakhalin Island, north of Japan. Thirteen years and three generations later, the percentage of tame river otters at the farm had more than tripled, from around 10 per cent initially. These animals also boasted lighter markings, earlier reproduction and changes in brain chemistry.
The results of these experiments suggest that Belyaev was right: far from the characteristic features of domesticated mammals requiring hundreds of generations of selective breeding, they start to appear in just a few. With all the animals, selecting for tameness brought with it new colour variants and altered reproduction, in fact pretty much all the features typical of a domesticated species. According to Lyudmila Trut, who took charge of the experiments after Belyaev's death in 1985, part of the reason is that breeding for tameness produces changes in the timing of developmental processes.
With the break-up of the Soviet Union in the early 1990s, these ground-breaking experiments ran into difficulty. By the end of the decade, with little money for food or salaries, the IC&G was forced to reduce the number of breeding foxes from 700 to just 100 and the number of mink from over 6000 to around 1000. The otter programme did not survive the funding crisis, though some of the tame animals and their descendants can still be seen at Moscow Zoo.
Things began to look up after Pääbo came to see the foxes. After some negotiation, Trut agreed to establish colonies of tame and aggressive rats in Germany to allow the genetic changes in the animals to be identified. "It took over a year to get everything in place," says Pääbo. When, in late 2005, 15 tame and 15 aggressive rats left Novosibirsk, they were chaperoned all the way to Leipzig by IC&G staff.
One of the first things the team in Germany did was to check that the differences in the rats' behaviour really are due to nature, not nurture. To do this, they swapped the offspring shortly after birth, so pups born of tame parents were being reared by aggressive mothers and vice versa. If the post-natal environment has an influence, aggressive pups reared by tame mothers would become tamer. "We did not see that at all," says Frank Albert, who led the study (Hormones and Behaviour, vol 53, p 413). The cross-fostered rats behaved exactly like their genetic parents, he says.
There is still the possibility that the hormones sloshing around during pregnancy might alter fetal development and hence behaviour. Ruling this out requires switching embryos between mothers, which has yet to be done in rats. It has, however, been done in the silver foxes and had no obvious effect.
So, confident that the differences in behaviour are down to gene variants, the researchers set out to find them. They could not simply compare the DNA of the tame and aggressive strains, since many of the differences would have nothing to do with their behaviour - any two populations kept apart will diverge genetically even without selection, due to random mutations. Instead, they cross-bred the rats. The second generation of hybrids had a spectrum of behaviour from exceedingly tame to monstrously aggressive.
The next task was to measure tameness, for which they used the "glove test". Wearing two cotton gloves and a third made from chain mail, a researcher moves his or her hand slowly towards the rat, attempts to touch it and pick it up. "You can do anything with the tame rats," says Albert. "You can touch them, you can pick them up, you can move them around, you can move their arms and legs." The chain mail is there for the aggressive rats. "The moment you open the cage door some of them will come flying at the glove, bite it, latch on and scream," he says. "After testing you sometimes have bruises on your fingers."
Each glove test is videoed, so researchers who have no direct contact with the rats can objectively rate how tame or aggressive they are. The team then compared the behavioural scores with 200 genetic markers. Their preliminary findings, published in June this year (Genetics, vol 182, p 541), highlight several key regions of the genome that have a strong effect on tameness. "There are at least five genes, probably more, that are having a very complex interaction," says Albert.
The mission is now to home in on what these genes are and exactly what they do. If there are multiple mutations, each with a small effect on behaviour, this will be pretty challenging, says Leif Andersson, a geneticist at Uppsala University in Sweden involved in the project. "However, one of our loci has a major effect and influences both behaviour and the size of the adrenal gland," he says. "I am optimistic that we will be able to reveal the mutation and the gene underlying this major effect within a couple of years."
Network of genes
Given enough time, more painstaking work and a bit of luck, it seems likely the researchers will identify the entire network of genes responsible for tameness and aggression in rats. "Once we have them, we will of course see if the same genes and the same physiological pathways differentiate domesticated animals from their wild relatives," says Albert. "It might be a general thing."
Indeed, the same genes might turn out to underlie social behaviour in a wide range of mammals - including us (see "The tame ape" below article). Trut sees many similarities between the silver foxes and humans, for instance. "The range of behaviours in these foxes has significant parallels to that of normal and disordered patterns of human sociability," she says. She hopes pharmaceutical companies will start using the silver foxes to investigate potential therapies for behavioural problems. Selling the foxes as pets could be another potential source of income for the struggling IC&G. According to Trut, they make good pets, as devoted as dogs but as independent as cats.
If there is a common genetic basis for domestication, the work of Pääbo and Albert could make it much easier to domesticate other species. Take the African buffalo, for example. It is notoriously aggressive, killing more people each year than lions. The benefits of creating a line of less volatile - even friendly - buffalo would be enormous. As these animals are well adapted to local conditions, they would make for a more robust herd than domesticated cattle. Domesticating them might simply be a question of screening buffalo to find some with the right genes, and setting up some suitable pairings. If this failed, there would be the prospect of tinkering more directly with the African buffalo genome.
Some people will object to the very notion of domesticating more wild species, whether for farms or as pets. But many tame animals, such as dogs, cats, horses, sheep, now far outnumber their wild relatives. Wouldn't it be better if some threatened animals survived as pets or farm animals rather than not at all?
There is also a certain appeal to the idea of taming exotic creatures. Take zebras. While a few individuals have managed to ride them, they have never been fully tamed. "Maybe we have not tried hard enough to find zebras that are suitable for domestication," suggests Andersson. If Pääbo's genetic quest reveals the secret to taming the zebra, Royal Ascot might never be the same again.
The tame ape
Perhaps we are also a product of domestication. Over the last 30,000 years, human brain size, tooth size and jaw size have all been on the decrease - exactly the same kind of changes that have occurred as animals such as dogs were domesticated, says Richard Wrangham, a biological anthropologist at Harvard University. This raises the intriguing possibility that humans have been on an evolutionary journey from aggressive chimpanzee-like ancestor to the relatively tame species we are today.
If this is the case, who did the domesticating? The answer, suggests Wrangham, is that we did. Humans, he argues, are "self-domesticated apes", with natural selection favouring individuals that showed tame and cooperative behaviour, and weeding out the more aggressive and antagonistic among us.
Henry Nicholls is a science journalist based in London. He is writing Political Animal, a book about pandas and China to be published by Profile in 2010
We've had two cats for 11 years and I can relate to this domi. One of them loved to jump up on the bed and wait for us to toss a Q-tip up in the air so she could jump after it and toss it about herself for a bit, then wait for us to toss it again, kind of like your bating game. It's true, you really have to spend time getting to know them. They have such great personalities and can show much affection/compassion in their own way - or maybe that's just the way I'm perceiving it. When I get stressed out, there's nothing better than finding a warm curled up snoozing kitty to nuzzle into for a hug. That purring is just so soothing to me.domi said:Cats are definitely smarter than people give them credit for but you need to interact with them to bring it out in the feline-human relationship.
We have a few cats and some do "fetch" and it's great fun for both parties involved.
We also do "kitty baseball" where you throw a toy mouse and it gets batted back. Or "chase" where you go around in a circle through adjoining rooms trying to sneak up on each other which is quite a lot of fun when the kitty sees through your ruse.
fwiwIt seems that the measurable Hertz of a cat's purr lies between 25 and 150. Coincidentally (or not) it has been found that sound frequency in this range can stimilate bone growth and healing. ¹ A newer theory is that purring releases endorphins - natural analgesics that reduce pain while healing proceeds.
That cats have remarkable endurance, and are quite stoic to trauma is well known to veterinary professionals; it is not unlikely that this instinct to purr under duress is directly related.
Purring under stress has more colorfully been described as the cat's mantra, e.g., a self-soothing, self-healing, relaxing, vibrating sound (sort of like the Ommmm one might hum while in the lotus position. Notice the vibration in your lips, nose and throat? I bet most of us, if we had our "druthers," would much rather be able to purr!
One study determined that purring involves activation of nerves within the voice box. These nerve signals cause vibration of the vocal cords while the diaphragm serves as a piston pump, pushing air in and out of the vibrating cords, thus creating a musical hum. Veterinarian Neils C. Pederson, author of Feline Husbandry, believes that purring is initiated from within the central nervous system and is a voluntary act. In other words, cats purr only when they want to.²
yes, that is my theory also, I mentioned it on EE thread. very often you see cats with multiple fractures that purr like little machinesshellycheval said:Kessy mentioned "That purring is just so soothing to me." Me too--I wonder if it sets up some kind of entrainment of vibration frequency in us when we can feel/hear the purr?
I wonder if cats are stimulating their vagus nerve when they purr--I know they purr when they are content, but also have known them to purr when injured or extremely stressed. Purring is so strong; it affects the whole throat area so I'm thinking it must vibrate their vagus nerve--for the better.
that is one beautiful dog, what breed is it?Yes... our well-nourished cat, Penelope, regularly kills baby bunnies in the spring, baby squirrels, baby birds, and once in awhile, a mouse or mole (which is okay by me - I'm at war with the moles). Fair gives me the willies.
On the other hand, my baby just likes to talk to us, to play ball, and be loved as often as possible. And she is certainly as soft and fluffy as any cat!
(For more of our 2 D children: It's A Dog's Life! )