Cheryl Wise

Origins and Divergence of the Roma (Gypsies)

The identification of a growing number of novel Mendelian disorders and private mutations in the Roma (Gypsies) points to their unique genetic heritage. Linguistic evidence suggests that they are of diverse Indian origins. Their social structure within Europe resembles that of the jatis of India, where the endogamous group, often defined by profession, is the primary unit. Genetic studies have reported dramatic differences in the frequencies of mutations and neutral polymorphisms in different Romani populations. However, these studies have not resolved ambiguities regarding the origins and relatedness of Romani populations. In this study, we examine the genetic structure of 14 well-defined Romani populations. Y-chromosome and mtDNA markers of different mutability were analyzed in a total of 275 individuals. Asian Y-chromosome haplogroup VI-68, defined by a mutation at the M82 locus, was present in all 14 populations and accounted for 44.8% of Romani Y chromosomes. Asian mtDNA-haplogroup M was also identified in all Romani populations and accounted for 26.5% of female lineages in the sample. Limited diversity within these two haplogroups, measured by the variation at eight short-tandem-repeat loci for the Y chromosome, and sequencing of the HVS1 for the mtDNA are consistent with a small group of founders splitting from a single ethnic population in the Indian subcontinent. Principal-components analysis and analysis of molecular variance indicate that genetic structure in extant endogamous Romani populations has been shaped by genetic drift and differential admixture and correlates with the migrational history of the Roma in Europe. By contrast, social organization and professional group divisions appear to be the product of a more recent restitution of the caste system of India.

The Prevalence and Molecular Basis of Hemoglobinopathies in Cambodia

Blood counts, hemoglobin (Hb) high performance liquid chromatography (HPLC), and DNA analyses were performed on 260 children, aged 5 months to 16 years, at Siem Reap to assess the prevalence of thalassemia and other hemoglobinopathies in regional Cambodia. Hemoglobinopathies were present in 134 children (51.5%) with 20 abnormal genotypes identified. α-Thalassemia (thal) (35.4%) was the most prevalent disorder and the –α3.7 gene deletion was the most common α-globin gene abnormality. The − −SEA deletion and nondeletional forms of α-thal, Hb Constant Spring [Hb CS, α142, Term→Gln, TAA→CAA (α2)], Hb Paksé [α142, Term→Tyr, TAA→TAT (α2)] and triplicated α genes, were also present but at low frequencies. Hb E [β26(B8)Glu→Lys, GAG→AAG] (28.8%) was the most common β-globin gene abnormality, whilst β-thal was only detected in two children (0.8% of cases). Although hemoglobinopathies were common, the majority of abnormalities detected (heterozygous −α3.7 and Hb E) were not clinically significant. On the basis of these findings, and with the majority of abnormalities being mild, it seems improbable that thalassemia represents a major health burden in this region of Cambodia.

Genetic ancestries in northwest Cambodia

A survey of the genetic ancestry of 125 Cambodian children resident in Siem Reap province was undertaken, based on eight Y-chromosome binary polymorphisms and sequencing of the mtDNA HV1 region. The data indicated a largely East Asian paternal ancestry and a local Southeast Asian maternal ancestry. The presence of Y-chromosomes P* and R1a1* was suggestive of a small but significant Indo-European male ancestral component, which probably reflects the history of Indian, and later European, influences on Cambodia.