Browsing by Author "Moraga, M"

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    Genotypic interaction between DRD4 and DAT1 loci is a high risk factor for attention-deficit/hyperactivity disorder in Chilean families
    (WILEY, 2006) Carrasco, X; Rothhammer, P; Moraga, M; Henriquez, H; Chakraborty, R; Aboitiz, F; Rothhammer, F
    Attention-deficit/hyperactivity disorder, ADHD [MIM 126452], is a common, highly heritable neurobiological disorder of childhood onset, characterized by hyperactivity, impulsiveness, and/or inattentiveness. As part of an ongoing study of AMID, we carried out a family-based discordant sib-pair analysis to detect possible associations between dopamine receptor D4 (DRD4) and dopamine transporter 1 (DAT1) polymorphisms and ADHD in Chilean families. Both loci individually classified as homozygotes or heterozygotes for the DRD4 7-repeat and DAT1 10-repeat alleles, did not exhibit genotype frequency differences between affected children and their healthy siblings (Fisher's exact test P > 0.25 in both cases). However, the simultaneous presence of both DRD4 7-repeat heterozygosity and DAT1 10 allele homozygosity were significantly higher (34.6%) in cases (26), compared with their unaffected siblings (25) (4%; Fisher's exact test P = 0.0096; odds-ratio, OR = 12.71). Increased density of dopamine transporter in ADHD brains, along with abundance of 7-repeat D4 receptors in prefrontal cortex, which is impaired in ADHD patients, make the observed gene-gene interaction worthy of further incisive studies. (C) 2005 Wiley-Liss, Inc.
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    Origin and evolutionary relationships of native Andean populations
    (2001) Rothhammer, F; Llop, E; Carvallo, P; Moraga, M
    This paper represents an effort to explore the origin and the evolutionary relationships of native Andean populations using a multidisciplinary approach. Archeological and linguistic evidence is briefly reviewed. A genetic distance analysis among major linguistic groupings and among Andean and Amazonian native populations, together with information obtained from archaeological and linguistic sources was used to generate a migration model. It is suggested that in the late Pleistocene a group of nomadic hunters entered South America through the Isthmus of Panama and split afterwards into two groups, one moving southward into the central and south Andean areas and after crossing the Colombian, Equador and Peruvian highlands to people northwestern Argentina, the open park country of east Brazil and the Argentine Pampas. The second group migrated eastwards into Venezuela and Guyana and later southward, peopling the Brazilian Amazon. Following available waterways the Amazonian Indians expanded east and west arriving probably at the eastern slopes of the Andes some 3,500 years ago. It is hypothesized that present day Andean natives are descendants of the Amazonian groups that migrated eastwards.