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Examination of ancient and contemporary Native American mtDNA variation via diagnostic restriction sites and the 9-pb Region V deletion suggests a single wave of migration into the New World. This is in contrast to data from Torroni et al. which suggested two waves of migration into the New World (the NaDene and Amerind). All four founding lineage types are present in populations in North, Central, and South America suggesting that all four lineages came over together and spead throughout the New World. Ancient Native American DNA shows that all four lineages were present before European contact in North America, and at least two were present in South America. The presence of all four lineages in the NaDene and the Amerinds argues against separate migrations founding these two groups, although admixture between the groups is still a viable explanation for the presence of all four types in the NaDene. [ABSTRACT FROM AUTHOR]

Aldehyde dehydrogenase deficiency, N-acetyltransferase variation and the polymorphisms of α-antitrypsin, serum cholinesterase, paraoxonase, and δ-aminolevulinic acid dehydratase were investigated in 180 Atacameño Indians from the North of Chile. The genetic predisposition of these individuals for possible atypical reactions against environmental agents and drugs, as well as general implications of these findings, are discussed. [ABSTRACT FROM AUTHOR]

The distribution of the human liver alcohol dehydrogenase, ADH, and aldehyde dehydrogenase, ALDH2, genotypes in 21 different populations comprising Mongoloids, Caucasoids, and Negroids was determined by hybridization of the amplified genomic DNA with allele-specific oligonucleotide probes. Whereas the frequency of the ADHallele was found to be relatively high in the Caucasoids, Mexican Mestizos, Brazilian Indios, Swedish Lapps, Papua New Guineans and Negroids, the frequency of the ADHgene was considerably higher in the Mongoloids and Australian Aborigines. The atypical ALDH2 gene (ALDH2) was found to be extremely rare in Caucasoids, Negroids, Papua New Guineans, Australian Aborigines and Aurocanians (South Chile). In contrast, this mutant gene was found to be widely prevalent among the Mongoloids. Individuals possessing the abnormal ALDH2 gene show alcohol-related sensitivity responses (e.g. facial flushing), have the tendency not to be habitual drinkers, and apparently suffer less from alcoholism and alcohol-related liver disease. [ABSTRACT FROM AUTHOR]

Introduction: Not all ADHD subjects respond equally to stimulants Methods: We analyzed the clinical response, CPT performance and DAT1 polymorphism of 73 ADHD patients 8–14 years of age (13 girls) after 1 year of stimulant treatment. Results: (1) A positive correlation between CPT performance and clinical response; (2) clinical response depends on comorbidities while CPT performance does not; (3) the clinically responding group shows a higher IQ than the nonresponding group; (4) children displaying little improvement in the CPT test after treatment have a higher frequency of the DAT1 9R allele (χ2 p 0.02); but clinical response is independent of DAT1 polymorphism. Conclusion: CPT and genetics are good predictors of stimulant response. FONDECYT 1070761 and 1080219. [ABSTRACT FROM AUTHOR]