Natural Selection is daily and hourly scrutinising, throughout the world, the slightest variations; rejecting those that are bad, preserving and adding up all that are good.
C.DARWIN sixth edition Origin of Species — Ch#4 Natural Selection
NOT! Newly appearing good traits in a single individual will rarely get infused (or “fixed” ) into a population. To understand theoretically why this is false, visit: Gambler’s Ruin is Darwin’s Ruin.
And now we have some poignant experimental confirmation of my theoretical prediction! In a paper published by the prestigious scientific journal Nature September 30,2010 we read:
Our work provides a new perspective on the genetic basis of adaptation. Despite decades of sustained selection in relatively small, sexually reproducing laboratory populations, selection did not lead to the fixation of newly arising unconditionally advantageous alleles. This is notable because in wild populations we expect the strength of natural selection to be less intense and the environment unlikely to remain constant for ~600 generations.”
Consequently, the probability of fixation in wild populations should be even lower than its likelihood in these experiments. This suggests that selection does not readily expunge genetic variation in sexual populations, a finding which in turn should motivate efforts to discover why this is seemingly the case.”