4 ms·

Sadly the gene has to give some advantage to its bearer to actually spread in the population. With only future benefits, i does not spread.

• gmoot 3y ago
  This is not true, it can spread. It's called neutral evolution.
  • samus 3y ago
    It might also just as well disappear again. It's random after all, and when that happens we call it genetic drift. However, it's rare for a gene to be truly neutral.