There are two types of Genetic Drift, First one is bottle neck and the second one is founder effect. They both have similar things, they compare to each other. Genetic drift is the concept that there is a chance of variation in a small population that can affect everyone. For instance we have a colony of human crayons blue, purple, a couple of oranges and one red. A plague hits the town and kills off the blue and we are only left with the orange, purple and the one red. In the Bottle neck effect only a few of the members of the population survive to pass on genes. We will use the same concept in a colony of human crayons purple, and one red. Only the Purple survived, and the red dies we no longer have the red gene.
In the founder effect it