[space_cowboy]

Exceptions that prove the rule, because of historical migration and trade patterns that link those areas. Identical recurrent mutations in the human genome are rare.

Do you believe that if you took a mitochondrial DNA sample from an Indian, a Chinese person, a person of European descent, and an African living in America that a researcher would not be able to tell the difference?

[aswanson]

Not sure, depends upon the specific case -- probably correct in a wide, stochastic sense.

Immaterial, though. I was merely refuting your incorrect statement in the GP.

[tokenadult]

Exceptions that prove the rule

http://en.wikipedia.org/wiki/Exception_that_proves_the_rule

http://ghr.nlm.nih.gov/condition=sicklecelldisease