The morphology of the first wolf population domesticated by humans was for a WOLF morphology - not a giant Great Dane or a yappy terrier, no down ears, no webbed feet, no short stubby legs, no pushed in muzzles, etc, etc.
The combined genetic variation in all dog breeds is MUCH LARGER than the genetic variations in wolves - let alone that small population of wolves that humans domesticated.
One does not get webbed feet in Labradors by mixing the right combination of wolf DNA already present in wolf populations - one must await a spontaneous mutation (they are not that uncommon) for webbed feet and breed for that trait.
Is it your position that yappy terrier have a different gene sequence than labradors?