Genes link people of Madagascar to Borneo
The Malagasy people of Madagascar carry the genes from ancestors in both nearby east Africa and also distant Borneo, a finding researchers say suggests a big migration from Asia back to Africa 2,000 years ago.
The genetic study supports the puzzling finding that the Malagasy language more closely resembles Indonesian dialects than east African tongues but does little to answer the question of how the settlers arrived.
Madagascar, the largest island in the Indian Ocean, lies 400 kilometres off the coast of Africa and is 6,400 kilometres from Indonesia.
Its long isolation has led to the evolution of unique animals, including lemurs, rare birds and plants.
A team of genetics experts at the universities of Cambridge, Oxford and Leicester looked at both the Y chromosomes of Madagascar residents, inherited virtually unchanged from father to son, and the mitochondrial DNA, passed directly from mothers to their children.
Tiny mutations in these two forms of DNA provide a kind of genetic clock that can help scientists trace human migration and inheritance.
The results showed clear similarities to sequences found on the island of Borneo, now shared by Indonesia, Malaysia and Brunei, according to Matthew Hurles of the Wellcome Trust Sanger Institute at Cambridge, who helped lead the study.
"The origins of the language spoken in Madagascar, Malagasy, suggested Indonesian connections, because its closest relative is the Maanyan language, spoken in southern Borneo," Mr Hurles said.
"Malagasy peoples are a roughly 50:50 mix of two ancestral groups: Indonesians and East Africans.
"It is important to realise that these lineages have intermingled over intervening centuries since settlement, so modern Malagasy have ancestry in both Indonesia and Africa."
The findings suggest a substantial migration from south-east Asia between 1,500 and 2,000 years ago, the researchers report in the American Journal of Human Genetics.