Absolutely this could happen. To the dog/cat/horse theory that has been presented. Do you really think that dogs just appeared and were automatically pack animals seeking each other out? I'm sure it took time for them to evolve and realize that seeking each other out meant protection. And then in one to two thousand years we have produced tiny fluffy dogs that could barely live a day in the wild without a human feeding them. Given reptiles ARE a totally different area, but I think this is completely plausible.