The minimum amount of people needed to populate a space colony with minimum inbreeding would be 160. A space colony, or a moon or Mars colony, might sound like something pretty cool, until you consider the small available gene pool after a few generations.
Sure, in theory you could just Adam and Eve it up there, starting with only two people. But obviously that introduces problems once you reach generation two. While, according to geneticists, Adam and Eve (or Y Chromosomal Adam and Mitochondrial Eve, as they’re called) had the genetic information to produce all the humans on the earth, it wouldn’t be possible to replicate that.
The number, according to geneticists, comes to 160 people- 80 men and 80 women. This of course depends on the variance in genes, so these people would all need to be as distantly related as possible. While some animals are all genetically the same, humans need a pretty big gene pool to not turn out abnormally.
In a colony started of only 2 people, inbreeding would create numerous health problems and likely lead to an extinction of the colonists after enough time. So remember kids: inbreeding bad, large gene pools good.