5 replies to this topic

[yeehi]

For selective breeding in mammalian sexual reproduction, about how many generations would need to pass before a new species came into being, one that could no longer successfully breed with the starting stock?

[bob1]

Pick a number... what do you know about selection pressure?

[yeehi]

bob1, on May 10 2010, 01:40 AM, said:

Pick a number... what do you know about selection pressure?

I am unfamiliar with selection pressure. In a laboratory setting it would be possible to select for individuals with a particular trait, putting selection pressure at its maximum.  Being prevented by an external agent from reproducing isn´t what counts in determining whether a new species has formed, though.

If selection pressure is at its maximum, how many generations would it take, I wonder. I don´t think it is known.

[HomeBrew]

It depends on the mechanism of speciation (see here).  There is no way to know in advance how many generations such an event would take to occur.

[hobglobin]

To give a number, sometimes even one generation may be enough, i.e. one mutation that then via selection or building a reproductive barrier separates the populations. But this is a very, very rare event, as the mutation has to spread and not eradicated or just outnumbered in a large population.
Here is an example, with an approximately way how it could work.

[Maddie]

Thanks for this article hobglobin. It's very interesting.