Biomedical subjects
Publications and source records attributed to F Rothhammer.
Gene frequencies for 13 marker systems are used to construct synthetic gene frequency maps of South America. The surfaces generated using the first three principal components exhibit clines which validate models of population displacement based on archeological data and a previous analysis of craniometrical variation.
Mummies' demographic information of 10 prehispanic cultures that developed in the Arica region of Chile about 7000 years ago is analyzed and related to the present population structure. A paleoepidemiological analysis supports a relationship between cultural development and demographic structure. In chronological sequence, 4 demographic patterns can be distinguished: 1) archaic, a mature population with the highest life expectancy and the lowest dependence from prehispanic populations; 2) later archaic, a population in demographic explosion with its larger fraction under 15 years of age, elevated fertility rates and the greatest prehispanic dependence; 3) andean, a transition population with moderate fertility rates and dependence index; and 4) modern, an aging population with the highest proportion over 45 years of age and the highest life expectancy. The present demographic analysis may help to understand the relationships among disease, individual and culture from the perspective of genetic epidemiology.
Chagas disease is present in northern and central Chile. Not more than 25% of infected individuals have had a pathologic condition presumably due to Trypanosoma cruzi. The majority of individuals with chronic infectious Chagas disease in Chile are asymptomatic in contrast to what has been observed in other South American countries. Historic and paleopathologic evidences suggest that this particular behavior could be explained by a genetic adaptation of Chilean aborigines to T cruzi. Associations between ethnic admixture, presence of Chagas disease, associated cardiac pathology and 4 blood groups (ABO, MNSs, Rh and Duffy) were investigated among inhabitants of San Pedro de Atacama in northern Chile. Cardiac pathology was determined by positive serologic reactions in individuals with abnormal electrocardiographic findings. Individuals with negative serologic results had a significantly greater aboriginal admixture (88%) compared to those with positive serology (66%). This findings supports the hypothesis of genetic adaptation explaining mildness of Chagas disease in Chile.
We have analyzed the allele frequency distribution at the hypervariable locus 3' to the apolipoprotein B gene (ApoB 3' VNTR) in five well-defined human populations (Kacharis of northeast India, New Guinea Highlanders of Papua New Guinea, Dogrib Indians of Canada, Pehuenche Indians of Chile, and a relatively homogeneous Caucasian population of northern German extraction) by using the PCR technique. A total of 12 segregating alleles were detected in the pooled sample of 319 individuals. A fairly consistent bimodal pattern of allele frequency distribution, apparent in most of these geographically and genetically diverse populations, suggests that the ApoB 3' VNTR polymorphism predates the geographic dispersal of ancestral human populations. In spite of the observed high degree of polymorphism at this locus (expected heterozygosity levels 55%-78%), the genotype distributions in all populations (irrespective of their tribal or cosmopolitan nature) conform to their respective Hardy-Weinberg predictions. Furthermore, analysis of the congruence between expected heterozygosity and the observed number of alleles reveals that, in general, the allele frequency distributions at this locus are in agreement with the predictions of the classical mutation-drift models. The data also show that alleles that are shared by all populations have the highest average frequency within populations. These findings demonstrate the potential utility of highly informative hypervariable loci such as the ApoB 3' VNTR locus in population genetic research, as well as in forensic medicine and determination of biological relatedness of individuals.
We studied the distribution of HLA, B and C antigens in 73 Chagasic subjects with and without heart disease. Both groups were matched for age, sex, birth place and history of family residence. Thirty two subjects without evidence of Chagasic infection, with and without heart disease and matched for the same variables were also studied. Compared to all other groups, a significant increase in the level of the B40 Cw3 antigen combination was found in Chagasic subjects without evidence of heart disease.
The independent contributions of climate, altitude, chronology, and geographic location of archeological sites to craniometrical variation are analyzed in a sample of 1,119 skulls from South America. Geographic location is responsible for the highest proportion of craniometrical variation, followed by climate and altitude. It is concluded that geographic isolation has partially prevented gene flow from counterbalancing craniometrical microdifferentiation produced by founder effect.
Using the polymerase chain reaction to amplify genomic DNA from hair roots, we have examined the mitochondrial aldehyde dehydrogenase (ALDH2) genotypes of 28 individuals from the South American Mapuche Indians. We have determined that individuals from this population previously reported to lack (ALDH2) activity do not show the presence of the inactive (ALDH2(2] allele frequently found in Orientals.
Archeological, craniometrical, and genetic information is utilized to reconstruct possible migration routes used in the peopling of Andean South America. Special emphasis is given to the elaboration of craniometrical isoline maps and its application in testing models of population displacement based on archeological data. A genetic distance analysis among linguistic groupings complements the conclusions based on archeological and craniometrical information.
Myths and facts concerning the heredity of human alcohol abuse are discussed in this article. Familial aggregation, adoption studies, twin concordances, marker gene associations and, finally, recent biochemical and genetic evidence are examined critically. It is concluded that with the exception of a possible protective action of the ALDH2 gene in Japanese there is a lack of clear cut evidence with respect to the direct participation of genetic factors in human alcoholism.
The results of ABO typing in Chilean mummies, a review of published South American paleoserological studies and a systematic discrepancy of admixture estimates based on ABO and Gm genes support the hypothesis that Andean pre-Columbian populations possessed the A (and perhaps the B) gene in small frequencies.
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The distribution of HLA antigens in a sample of 124 Chagas serologically positive Chilean individuals was studied. The sample was subdivided according to the presence or absence of chagasic cardiomyopathy, in order to search for genetic differences associated with this pathological condition. The frequency of antigen B40 in the presence of antigen Cw3 was found to be significantly lower in subjects with cardiomyopathy. We tentatively suggest that the presence of these antigens among noncardiomyopathics is associated with a decreased susceptibility to develop chagasic cardiomyopathy in the Chilean population.
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While about 40% of the South American Indian populations (Atacameños, Mapuche, Shuara) were found to be deficient in aldehyde dehydrogenase isozyme I (ALDH2 or E2), preliminary investigations showed very low incidence of isozyme deficiency among North American natives (Sioux, Navajo) and Mexican Indians (mestizo). Possible implications of such trait differences on cross-cultural behavioral response to alcohol drinking are discussed.
The quest for the origin and dispersion of Chagas' disease, the second most important vector-borne disease in Latin America, has epidemiological, immunological, and genetical implications. Conjectures based on accounts of chroniclers, reviews of the archaeological literature and the present distribution of triatomine bugs, the vectors of the disease, held that the origin of the adaptation of Triatoma infestans (a species of the subfamily Triatominae) to human dwellings occurred in prehistoric times. The autopsy of 35 mummies exhumed in the Chilean desert, dated between 470 B.C. and 600 A.D., revealed the presence of clinical manifestations of Chagas' disease and put earlier speculations on a factual basis.
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Explore the source record for details and available documents.