Five kinds of changes to gene frequencies

[grayfalcon89]

I just learned about five kinds (maybe there are more but I only learned 5) and I want to be assured that what I know is correct.

 

The first one is random gentetic drift which frequency of an allele of gene varies from time to time by random. No one allele dominates over another completely.

 

The second one is natural selection ---survival of fittest--- which is the animal or allele that best adapts the environment survives.

 

The third one is artificial selection such that humans picking the horses to breed for the race. This is not the one who best survives on the environment determined by nature but rather humans, who wants to have "best" allele and manipulates over it.

 

 

The fourth one is founder's effect where out of many various alleles, the allele with small population, say allele that gives you 6 fingers (if there are only two people with 6 fingers on the room of 50 people with 44 that has 5 fingers) and starts out new population. The descendents of the population are same from founders. Ex. Amish in US

 

The fifth is bottlenecks which are similar to founder's effect except instead of one allele or two moving out, in bottleneck, only one or two survives and rest of them dies. So, the descendents coming out on the next generations are same to the ones who survived.

 

Are they right?

[Mokele]

Sexual selection (which could be considered a sub-set of natural selection)

 

Migration, new genes entering the gene pool from other populations.