5 ms·

I vaguely remember reading that if you randomly bred dogs they slowly revert back to the "original" kind (strays). Is that true?

by 323 5y ago

Frost1x 5y ago
Do you perhaps mean wolves by strays? If so,, I don't think that's how natural evolution works, otherwise humans might start looking like Homo erectus. The main distinction between an actual 'stray' dog and a domestic dog is environmental, being around humans and so on and less to do with genetics. If you let dogs breed freely they'd probably still clump into sets of similar genetic and physical traits based on time and location (and their prior genetics).
takk309 5y ago
That does bring up a good question, if one were to breed dogs at random from a very large pool of dogs, how many generations would it take to revert to a wolf-like dog? Of course some care would be needed to ensure the dogs were a compatible size, that is no St. Bernards crossed with corgis. For the sake of argument let's say 1,000 randomly selected medium (30 to 70 pounds) dogs as the initial pool and taking care to avoid inbreeding at least 5 generations back.
- gwern 5y ago
  Assuming no selection is involved, merely global mating completely at random where any dog could breed with any dog, they would never 'revert'. You would instead get a global average of current dogs, and then there would be a very wide bell curve around that mean, which would throw up lots of extremes at random. Genes are conserved, and get randomly distributed among offspring. It's like how red hair pops up in some families. The red hair gene never 'disappeared' or 'got averaged out', it just kept being passed on until it met another copy. Another example is interracial families: you might think that the kids would all 'look like' the average of the two parents, but sometimes one kid will look just like one parent even though they are biracial. (Apparently this can cause problems, like if a little blonde-haired blue-eyed girl is walking around with her dad from Africa.) On a historical note, this was a major issue for Darwin & Galton trying to come up with a statistical model of 'genes': the initial efforts of 'blending inheritance' predicted that everyone would quickly become the same height etc, which is both obviously not true (short parents can have tall kids and vice versa) and would mean evolution is impossible (no variation to select on!).

I vaguely remember reading that if you randomly bred dogs they slowly revert back to the "original" kind (strays). Is that true?

by 323 5y ago

I vaguely remember reading that if you randomly bred dogs they slowly revert back to the "original" kind (strays). Is that true?

Frost1x 5y ago

Do you perhaps mean wolves by strays? If so,, I don't think that's how natural evolution works, otherwise humans might start looking like Homo erectus. The main distinction between an actual 'stray' dog and a domestic dog is environmental, being around humans and so on and less to do with genetics. If you let dogs breed freely they'd probably still clump into sets of similar genetic and physical traits based on time and location (and their prior genetics).

takk309 5y ago

That does bring up a good question, if one were to breed dogs at random from a very large pool of dogs, how many generations would it take to revert to a wolf-like dog? Of course some care would be needed to ensure the dogs were a compatible size, that is no St. Bernards crossed with corgis. For the sake of argument let's say 1,000 randomly selected medium (30 to 70 pounds) dogs as the initial pool and taking care to avoid inbreeding at least 5 generations back.

gwern 5y ago
Assuming no selection is involved, merely global mating completely at random where any dog could breed with any dog, they would never 'revert'. You would instead get a global average of current dogs, and then there would be a very wide bell curve around that mean, which would throw up lots of extremes at random. Genes are conserved, and get randomly distributed among offspring. It's like how red hair pops up in some families. The red hair gene never 'disappeared' or 'got averaged out', it just kept being passed on until it met another copy. Another example is interracial families: you might think that the kids would all 'look like' the average of the two parents, but sometimes one kid will look just like one parent even though they are biracial. (Apparently this can cause problems, like if a little blonde-haired blue-eyed girl is walking around with her dad from Africa.) On a historical note, this was a major issue for Darwin & Galton trying to come up with a statistical model of 'genes': the initial efforts of 'blending inheritance' predicted that everyone would quickly become the same height etc, which is both obviously not true (short parents can have tall kids and vice versa) and would mean evolution is impossible (no variation to select on!).