Africans
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While Africa has been known as the continent where modern humans originated, a new study finds Africans to be the most genetically diverse people in the world.

Scientists say all humans are the direct descendents of people living about 200,000 years ago in the homeland of the San people along the Namibia-South Africa border.

According to the report published in the journal Science Express, researchers found that nearly three-fourths of African-Americans can trace their ancestry to West Africa.

"Given the fact that modern humans arose in Africa, they have had time to accumulate dramatic changes" in their genes, AP quoted lead researcher Sarah Tishkoff of Pennsylvania University.

The study aimed to find the reason why diseases have a greater impact in some groups than others and discover ways to provide medical treatment for African groups as a homogenous society.

According to Tishkoff, the so-called 'Cape-colored' population of South Africa has the world's highest levels of mixed ancestry, a blend of African, European, East Asian and South Indian.

Although researchers found "little evidence" for American Indian genes among African-Americans, the study showed that about 71 percent of African-Americans have western African origins.

They also have between 13 and 15 percent European ancestry and a smaller amount of other African origins.

Some local African-Americans, including those living on the Sea Islands off Georgia and South Carolina, come from Sierra Leone and Guinea.