>Swedish research, a bi-product of building a database of genes from
all dog-races of the world, has concluded that dogs inherit from
four female wolves 100-130 kya. One of these is the ancestor of one
single dog-race (swedish jamthund), so all other races share
the other three ancestors. Mitocondrial dna was the base for this,
that is why inheritance on the female side is known only.>



Mitochondrial DNA was also the base for the UCLA study.  From the
introduction of "Multiple and Ancient Origins of the Domestic Dog," Charles
Villa, et al (Science, June, 1998), authored by the UCLA researchers:

"Mitochondrial DNA control region sequences were analyzed from 162 wolves
at 27 localities worldwide and from 140 domestic dogs representing 67
breeds.  Sequences from both dogs and wolves showed considerable diversity
and supported the hypothesis that wolves were the ancestors of dogs.  Most
dog sequences belonged to a divergent monophyletic clade sharing no
sequences with wolves.  The sequence divergence within this clade suggested
that dogs originated more thn 100,000 years before the present. 
Associations of dog haplotypes with other wolf lineages indicated episodes
of admixture between wolves and dogs.  Repeated genetic exchange between
dog and wolf populations may have been an important source of variation for
artificial selection."

The latter part of the article points out:

".... bones of wolves have been found in association with those of hominids
from as early as the middle Pleistocene, up to 400,000 years ago.  The
ancient dates for domestication based on the control region sequences
cannot be explained by the retention of  ancestral wolf lineages because
clade 1 is exclusively monophyletic with respect to dog sequences and thus
the separation between dogs and wolves has been long enough for coalescence
to have occurred.  To explain the discrepancy in dates, we hypothesize that
early domestic dogs may not have been morphologically distinct from their
wild relatives.  Conceivably, the change arond 10,000 to 15,000 years ago
from nomadic hunter-gatherer societies to more sedentary agricultural
population centers may have imposed new selective regimes on dogs that
resulted in marked phenotypic divergence from wild wolves."

"Although individual breeds show uniformity with respect to behavior and
morphology, most breeds show evidence of a genetically diverse heritage
because they contain different haplotypes.  Moreover, dog sequences cluster
with different groups of wolf haplotypes.  Therefore, after the origin of
dogs from a wolf ancestor, dogs and wolves may have continued to exchange
genes.  Backcrossing events could have provided part of the raw material
for artificial selection and for the extraordinary degree of phenotypic
diversity in the domestic dog."



Lynda Bryson
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