[Verginius Rufus]

From a book published in 1977: "It is now believed that the inhabitants of Madagascar are descendants of settlers from present-day Indonesia (perhaps the island of Borneo), who arrived between 1,500 and 2,000 years ago."

The channel between Africa and Madagascar is comparable in width to the Mediterranean Sea between Greece and North Africa...the inhabitants of mainland Africa had no idea there was a major landmass beyond the horizon. The Malayo-Polynesian population got there first, and later imported people from the mainland, which is why there is African DNA but no African languages among the people of Madagascar. Something similar happened with the Cape Verde Islands.

[blam]

"The Malayo-Polynesian population got there first, and later imported people from the mainland, which is why there is African DNA but no African languages among the people of Madagascar."

Seems like the most reasonable explanation to me.