Genetic Affinities of the Siddis of South India: An Emigrant Population of East Africa

• Published in: Human biology 2008-06, Vol.80 (3), p.251-270
• Main Authors: Gauniyal, Mansi, Chahal, S. M S., Kshatriya, Gautam K.
• Format: Article
• Language: English
• Subjects: Ability tests; Admixtures; AFRICANS; Alleles; Alu Elements; ALU INSERTION-DELETION; AVERAGE HETEROZYGOSITY; Biological anthropology; Blood; Data collection; Demographic change; DNA; Emigrants; Emigration and Immigration; Enzymes; Epidemiology; Erythrocytes; Ethnic Groups; Evolutionary genetics; Gene Deletion; Gene Frequency; GENETIC ADMIXTURE; Genetic aspects; GENETIC DISTANCE; Genetic diversity; Genetic loci; Genetic Markers; Genetic Variation; Genetics, Population - statistics & numerical data; Human biology; Human genetics; Human population genetics; Humans; India; Indians; Indigenous peoples; Language; Linguistics; Mutagenesis, Insertional; NONRANDOM ASSOCIATION; Polymorphism, Genetic; Population; Population genetics; RED BLOOD CELL MARKERS; s; SEROLOGICAL MARKERS; SIDDIS; SOUTH INDIA; Studies
• ISSN: 0018-7143; 1534-6617; 1534-6617
• DOI: 10.3378/1534-6617-80.3.251

Historical records indicate that the Portuguese brought the African Siddis to Goa, India, as slaves about 500 years ago. Subsequently, the Siddis moved into the interior regions of the state of Karnataka, India, and have remained there ever since. Over time the Siddis have experienced considerable cultural changes because of their proximity to neighboring population groups. To understand the biological consequences of these changes, we studied the Siddis to determine the extent of genetic variation and the contributions from the African, European, and Indian ancestral populations. In the present study we typed the Siddis for 20 polymorphic serological, red cell, and Alu insertion-deletion loci. The overall pattern of phenotype (and genotype) distribution is in accordance with Hardy-Weinberg expectations. Considering the ethnohistorical records and the availability of secondary-source genetic data, we used two data sets in the analysis: one comprising eight serological and red cell enzyme markers with eight population groups and another comprising six Alu insertion-deletion markers with seven tribal groups of South India. The dendrograms generated from these two data sets on the basis of genetic distance analysis between the selected populations of African, European, and Indian descent reveals that the Siddis are closer to the Africans than they are to the South Indian populations. Genetic admixture analysis using a dihybrid model (19 loci) and a trihybrid model (10 loci and 8 loci) shows that the predominant influence comes from the Africans, a lesser contribution from the South Indians, and a slight contribution from the Portuguese. Thus the original composition of the African genes among the Siddis has been diluted to some extent by the contribution from southern Indian population groups. There is no nonrandom association of alleles among a set of 10 genetic marker systems considered in the present study. The demonstration of genetic homogeneity of the Siddis, despite their admixed origin, suggests the utility of this population for genetic and epidemiological studies.