Damage this, damage that, select this bad gene, that bad gene, and you get yourself docile floppy eared dog with the IQ equivalent of severe mental retardation, compared to a wolf.
Many breeds of dogs are certainly very dim compared to wolves, but I’m not so sure that some aren’t just as intelligent, perhaps more so. It can be difficult to evaluate the relative intelligence of dogs and wolves, because some of the hallmarks by which we measure the most intelligent dogs (such as the complexity of tasks they can be trained to perform) do not apply to wolves because they’re so much less cooperative.
Considering the intellectual tasks the smarter breeds of dogs are capable of though, I wouldn’t rule out the possibility of eugenic selection for intelligence relative to wolves, for e.g. border collies, standard poodles and such.
Thing is, of possible mutations within any gene (coding for a protein), vast majority cause loss of it’s original function. This makes the speed of evolution dramatically dependent to the specific details of how the change is accomplished.
Brain volume isn’t necessarily a very good proxy, some animals are significantly smarter than other animals which have larger brains. Rats, for instance, may be more intelligent than some animals which are capable of eating rats, and have much larger brains due to greater body volume.
The vast majority of the difference between dogs and wolves isn’t due to mutation, but selective concentration of genes which already existed within the grey wolf gene pool.
The vast majority of the difference between dogs and wolves isn’t due to mutation, but selective concentration of genes which already existed within the grey wolf gene pool.
As far as I remember, dogs are NOT domesticated wolves. Dogs and wolves have a common ancestor, but they diverged quite a while ago, possibly even before domestication. I vaguely recall that jackals were also somehow involved in dog ancestry.
The common ancestor of dogs and gray wolves, while perhaps having some differences with modern wolves, was still a gray wolf, and this is supported by the paper you linked below. While it’s true that modern gray wolves have less diversity than ancestral ones, what Desrtopa said is also correct.
I think this is incorrect, the most recent source I’ve read on the subject indicated that nearly the entire gene diversity out of all breeds of dogs is just a subset of the gene diversity that already existed in grey wolves.
The success in developing tame silver foxes with only a few generations of selective breeding suggests that domestic traits can be bred into canines without additional mutation just by imposing selection effects to sort for genes already existing within their population.
To identify genetic changes underlying dog domestication and reconstruct their early evolutionary history, we generated high-quality genome sequences from three gray wolves, one from each of the three putative centers of dog domestication, two basal dog lineages (Basenji and Dingo) and a golden jackal as an outgroup. Analysis of these sequences supports a demographic model in which dogs and wolves diverged through a dynamic process involving population bottlenecks in both lineages and post-divergence gene flow. In dogs, the domestication bottleneck involved at least a 16-fold reduction in population size, a much more severe bottleneck than estimated previously. A sharp bottleneck in wolves occurred soon after their divergence from dogs, implying that the pool of diversity from which dogs arose was substantially larger than represented by modern wolf populations. We narrow the plausible range for the date of initial dog domestication to an interval spanning 11–16 thousand years ago, predating the rise of agriculture.
Many breeds of dogs are certainly very dim compared to wolves, but I’m not so sure that some aren’t just as intelligent, perhaps more so. It can be difficult to evaluate the relative intelligence of dogs and wolves, because some of the hallmarks by which we measure the most intelligent dogs (such as the complexity of tasks they can be trained to perform) do not apply to wolves because they’re so much less cooperative.
Considering the intellectual tasks the smarter breeds of dogs are capable of though, I wouldn’t rule out the possibility of eugenic selection for intelligence relative to wolves, for e.g. border collies, standard poodles and such.
Wolves are under strong selection pressure as well, though.
Intelligence comparisons are of course tricky, but one could compare brain volumes as a proxy, and the comparison is not in favor of dogs.
Thing is, of possible mutations within any gene (coding for a protein), vast majority cause loss of it’s original function. This makes the speed of evolution dramatically dependent to the specific details of how the change is accomplished.
Brain volume isn’t necessarily a very good proxy, some animals are significantly smarter than other animals which have larger brains. Rats, for instance, may be more intelligent than some animals which are capable of eating rats, and have much larger brains due to greater body volume.
The vast majority of the difference between dogs and wolves isn’t due to mutation, but selective concentration of genes which already existed within the grey wolf gene pool.
As far as I remember, dogs are NOT domesticated wolves. Dogs and wolves have a common ancestor, but they diverged quite a while ago, possibly even before domestication. I vaguely recall that jackals were also somehow involved in dog ancestry.
The common ancestor of dogs and gray wolves, while perhaps having some differences with modern wolves, was still a gray wolf, and this is supported by the paper you linked below. While it’s true that modern gray wolves have less diversity than ancestral ones, what Desrtopa said is also correct.
I think this is incorrect, the most recent source I’ve read on the subject indicated that nearly the entire gene diversity out of all breeds of dogs is just a subset of the gene diversity that already existed in grey wolves.
WIkipedia also supports the contention that dogs are extracted directly from grey wolves a few tens of thousands of years ago, too recently for them to have diverged from some meaningfully distinct common ancestor.
The success in developing tame silver foxes with only a few generations of selective breeding suggests that domestic traits can be bred into canines without additional mutation just by imposing selection effects to sort for genes already existing within their population.
This claims otherwise. Notably:
To identify genetic changes underlying dog domestication and reconstruct their early evolutionary history, we generated high-quality genome sequences from three gray wolves, one from each of the three putative centers of dog domestication, two basal dog lineages (Basenji and Dingo) and a golden jackal as an outgroup. Analysis of these sequences supports a demographic model in which dogs and wolves diverged through a dynamic process involving population bottlenecks in both lineages and post-divergence gene flow. In dogs, the domestication bottleneck involved at least a 16-fold reduction in population size, a much more severe bottleneck than estimated previously. A sharp bottleneck in wolves occurred soon after their divergence from dogs, implying that the pool of diversity from which dogs arose was substantially larger than represented by modern wolf populations. We narrow the plausible range for the date of initial dog domestication to an interval spanning 11–16 thousand years ago, predating the rise of agriculture.