The First Dogs and and Genetic Drift

From Inbreeding and Genetic Diversity in Dogs: Results from DNA Analysis by Claire M. Wade:

The projected number of wolf founders of domestic dogs is 51 if the foundation event was closer to 16,000 years ago and could be as high as several hundred maternal founders if domestication was at the recent end of the projected range. This difference in estimates arises because time allows new mutations to accumulate, providing an alternative explanation for the diversity of haplotypes observed. It should be recognised that even founder females are likely to have carried a mixture of mitochondrial haplotypes

As this paragraph suggests, and as I have noted in the past, time, numbers, breeding habits, and generation length have a great deal to do with genetic variability. This is as true in dogs as it is in wolves.

The wolf-dog nexis is a particularly problematic fork to put a date on, as the wolf is:

1. a top predator, and big fierce predators are always rare due to their place in the food chain;
2. because only the top male and top female in a wolf pack will mate, and;
3. because wolves will only mate once a year.

Of course the domestication of the wolf at the hand of man has done several things.  It has:

1. increased the density of proto-wolves (i.e dogs and dog-morphs) on the landscape thanks to their association with man;
2. it has freed most domestic dog "packs" from the tyranny of having only the top male and top female mate, and;
3. it has increased the number of estrus's from one to two for most domestic dogs.

What's that mean?  Simply put it means if you are trying to pick a date for wolf-dog divergence, you are either going to have to pick a very wide time range, or you are going to have to make some assumptions for which there is, as yet, very little concrete evidence.

In fact, by at least one measure of speciation, a dog-wolf fork has not yet been made. After all, wolves, coyotes, domestic dogs, dingo, golden jackals, and New Guinea singing dogs can all interbreed and produce fertile young.
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