Saturday, July 09, 2011

CCMB Team Traces Siddis Ancestral Link to Africa

CCMB team traces Siddis ancestral link to Africa

Express News Service
09 Jul 2011 11:31:53 AM IST

HYDERABAD: The Centre for Cellular and Molecular Biology (CCMB) in a comprehensive genetic study, have discovered the African link to the Indian Siddis (Afro-Indians). The Siddis are mainly found in three states- Gujarat, Karnataka and a few hundred at Masab Tank in Hyderabad of Andhra Pradesh.

Speaking to reporters on the genetic findings on Friday, CCMB director Ch Mohan Rao and group leader Thangaraj said the Siddis have typical African features like dark skin, curly hair and a broad nose. Historically, it is known they were brought by Portuguese traders during the 17th-19th century and sold to Nawabs and Sultans, as soldiers and slaves.

The CCMB team undertook a comprehensive genetic study to address issues like which part of Africa they originated, the likely founder population of the Indian Siddis, mixing with the native Indian populations and the medical and social implications of mixing.

CCMB group leader Thangaraj said that they screened the Siddi population from Gujarat, Karantaka and Hyderabad with hundreds of genetic markers.

They selected three different sets of markers: Y-chromosome markers which are paternally inherited, mitochondrial DNA markers which are maternally inherited and autosomal markers, inherited from both parents.

Along with the Siddis, the team also analysed six populations who inhabited in close vicinity of Siddis.

The analysis revealed the Siddi population is a combination of ancestries, 70 per cent Africans and 30 percent Indians and Europeans. It has been further estimated they might have mixed with the neighbouring Indian populations about 200 years ago.

To trace the original parental population of Siddis, the CCMB team analysed the uni-parentally inherited markers. The results of paternally inherited (Y-chromosomes) revealed they are from Sub-Saharan Africa.

Interestingly, the presence of Indian-specific genetic signature in Siddis was observed but not vice-versa, suggesting a uni-directional geneflow from the Indian population to Siddis.

It was also observed that a genetic variant which originated in Africa about 5,000 years back to protect against malaria, has been found only in 10 percent of Siddi population.

This low frequency is mainly due to their mixing with the neighbouring Indian populations, which makes Indian Siddis more susceptible to malaria than their African ancestors.

No comments: