If all humans share a common ancestor, then how come we aren't all inbred?

Question

2nd answerer: What does cops have to do with it?

Answer 1

So you think Cops has only been on for 20 some odd years?

Answer 2

It is a very large population.  There probably was never a time when we had just one or two ancestors.  There are apparently a few times when our ancestors had small populations of several thousand.  There was certainly some inbreeding.  The important thing is that the one of those people a hundred thousand years ago had a particular mutation (for example) and that mutation was beneficial enough that eventually all surviving humans inherited it.  When we say we have a common ancestor with chimps, that last common ancestor involved a substantial population of apes that split into two populations of apes.  One population went on to be chimps and the other eventually led to us.

Answer 3

Common ancestor refers to a whole species.  It could be a few thousand or a several million individuals.

Answer 4

We are in the sense that people in isolated places like say britain or ireland have been reproductively isolated for years and their inbreeding coefficients are actually quite high. ireland for instance has a high level of cystic fibrosis and haemochromatosis.

In reality this inbreeding is countered by a low rate of mutation and a phenomenon called genetic drift sort of cheats to fix high levels of certain genes derived from a tiny percentage of the population. The much resisted notion of immigrants coming into your country or marrying outside of your race is actually a good idea as when 2 highly inbred peoples ( cultures) meet you get what they call inbreeding vigour i.e. the offspring are much healthier genetically and as the breeding increases you get the new genes fixed by drift in the overall population.

Inbreeding examples: racehorses are bred from a closed book and no new genes are introducable. Essentially, racehorses will be considered clones in 400 years unless they introduce new stock from outside the book

-cheetahs in africa suffered a reduction in number at the last ice age and essentially bred from about 100 cheetahs. As a result it is possible for one cheetah to donate skin to another with no immune rejection the two individuals are so alike

So inbreeding is for real and all populations need their immigrants with their inability to speak our lingo properly and taking our jobs as they say ( joke on racism) in order to improve their genetic stock......sorry KKK:)