The Sinodont dental morphology pattern of NE Asia is today more complex and was so by 20,000 years ago, than the simplified Sundadonty of SE Asia-Oceania, and the very simplified pattern that evolved greater than 20,000 B.P. All Native Americans are Sinodonts. Intra--and inter-hemispheric statistical analyses of 28 dental traits in greater than 6000 N & S American and greater than 1100 NE Asian crania reveal three temporally stable American sub-patterns, suggesting prior evolution in Sino-Siberia. The hypothesized biocultural associations and migration episodes are: (1) "Upper Cave" Sinodonts with the generalized Chinese Microlithic Tradition reach the Arctic steppe via the Lena basin to become Paleo--and most later Indians. (2) Smaller-game-hunting Siberian Diuktaians cross to Alaska at forest-forming terminal land bridge times to become Paleo-Arctic and subsequent Na-Dene-speaking NW forest Indians. (3) Lower Amur basin-N Japan blade-makingfolk evolve a coastal culture on the way to the land bridge's SE terminus at Anangula-Umnak where the oldest skeletons of the dentally distinctive but variable Aleut-Eskimos have been found.
Alu insertions provide useful markers for the study of inter-population affinities and historical processes, but data on these systems are not numerous in Native Americans and related populations.
The study aimed to answer the following questions: (a) do the population relationships found agree with ethnic, historical and geographical data? and (b) what can heterozygote levels and associated results inform us about the events that led to the colonization of the New World?
Twelve Alu insertion polymorphisms were studied in 330 individuals belonging to South American Native, Siberian and Mongolian populations. These data were integrated with those from 526 persons, to ascertain the relationships between Asian, Northern Arctic and Amerindian populations.
A decreasing trend concerning heterozygosities and amount of gene flow was observed in the three sets, in the order indicated above. Most results indicated the validity of these subdivisions. However, no clear structure could be observed within South American Natives, indicating the importance of dispersive (genetic drift, founder effects) factors in their differentiation.
The answers to the questions are: (a) yes; and (b) an initial moderate bottleneck, intensified by more recent historical events (isolation and inbreeding), can explain the current Amerindian pattern of diversity.
Native Americans have been divided into three linguistic groups: the reasonably well-defined Eskaleut and Nadene of northern North America and the highly heterogeneous Amerind of North, Central, and South America. The heterogeneity of the Amerinds has been proposed to be the result of either multiple independent migrations or a single ancient migration with extensive in situ radiation. To investigate the origin and interrelationship of the American Indians, we examined the mitochondrial DNA (mtDNA) variation in 87 Amerinds (Pima, Maya, and Ticuna of North, Central, and South America, respectively), 80 Nadene (Dogrib and Tlingit of northwest North America and Navajo of the southwest North America), and 153 Asians from 7 diverse populations. American Indian mtDNAs were found to be directly descended from five founding Asian mtDNAs and to cluster into four lineages, each characterized by a different rare Asian mtDNA marker. Lineage A is defined by a HaeIII site gain at np 663, lineage B by a 9-bp deletion between the COII and tRNA(Lys) genes, lineage C by a HincII site loss at np 13259, and lineage D by an AluI site loss at np 5176. The North, Central, and South America Amerinds were found to harbor all four lineages, demonstrating that the Amerinds originated from a common ancestral genetic stock. The genetic variation of three of the four Amerind lineages (A, C, and D) was similar with a mean value of 0.084%, whereas the sequence variation in the fourth lineage (B) was much lower, raising the possibility of an independent arrival. By contrast, the Nadene mtDNAs were predominantly from lineage A, with 27% of them having a Nadene-specific RsaI site loss at np 16329. The accumulated Nadene variation was only 0.021%. These results demonstrate that the Amerind mtDNAs arose from one or maybe two Asian migrations that were distinct from the migration of the Nadene and that the Amerind populations are about four times older than the Nadene.
This study was conducted to determine the location of arterial lesions in a population of Ecuadorian Mestizos with cerebral infarcts in the carotid territory caused by large-artery atherosclerosis.
Such patients were prospectively entered into a protocol of investigation that included cerebral angiography as the gold standard for evaluation of the extra and intracranial vascular bed.
Twelve (60%) of the 20 patients included in this study had symptomatic intracranial lesions, and the remaining 8 (40%) had extracranial lesions. Intracranial lesions were most often located in the middle cerebral artery stem. With the exception that systemic markers of arteriosclerosis were present in 3 of 8 patients with extracranial disease and in none of 12 patients with intracranial disease, we found no differences in stroke risk factors among patients with intra or extracranial lesions.
This study provides suggestive evidence that the distribution of arterial lesions in Ecuadorian mestizos with occlusive cerebrovascular disease is different from that in whites, but similar to that in blacks and orientals.
This overview revealed that substantial oral health inequalities exist between Indigenous and non-Indigenous child and adult populations in the United States, Canada, Brazil, Australia and New Zealand, with evidence suggesting that these inequalities are increasing. Despite the marked differences in geography, culture, language and history experienced by these groups, it is notable how similar the oral health inequalities were. A number of reasons are discussed in the paper.
While ethnobotany has emerged as an important discipline in the search for new drugs, this economic impetus should in no way distract from a more ethnobiological and equally critical goal--the codification and promotion of indigenous medical systems as a major factor in the conservation of biocultural diversity. Codification of indigenous medical systems requires a holistic view which entails (1) in-depth understanding of the recognized health conditions in the native system and how they might be described in terms of Western biomedicine; (2) comprehensive inventories of medicinal species employed in the native system, descriptions of their modes of preparation and administration and giving priority to those species most likely to merit pharmacological testing; and (3) identification of the pharmacological properties of these species with the goal of discovering how they might be effective in the treatment of the health conditions for which they are employed. Promotion of indigenous medical systems requires the development of local training programmes aimed at the active conservation and enhancement of traditional herbal medicinal therapies that have been shown to be pharmacologically effective in the treatment of symptoms of recognized health conditions. The establishment of such programmes is critical at a time when traditional medical systems are often disparaged as worthless by the national societies in which indigenous peoples live, as well as by younger members of the native populations themselves.
The GM immunoglobulin (Ig) allotype distributions of 49 native Amerindian populations from North to South America were analysed by a new technique called 'Mobile Sites Method' (MSM). This allows the global interpretation of genetic diversity in space by means of a distorted geographic map called a 'genetic similarity map'. This approach has been improved by superimposing in the distorted geographic map both the haplotype set (represented by hypothetical populations having a 100% frequency of the haplotype considered) and the 'geography-genetics discontinuities' (i.e. the zones between homogeneous population clusters). This bidimensional representation completes the interpretation of the genetic distances between populations in terms of local genetic diversity and possible migrations. Our results concerning the spatial distribution of the Amerindian populations show: (i) a great interdependence of the geographic locations and the GM haplotype distributions (the importance of the geographic factor was checked with the usual technique of 'random sampling' and the percentage of explained distance variability decreases from 78% with the observed data to a level less than 67% with the random data); (ii) a parallelism between genetics and linguistics groups as indicated by the population clusters in the similarity map, and (iii) a complex distorted map revealing the presence of multiple population migrations and admixtures in the course of time. A particular distortion of South America suggests possible migrations by sea along the western and eastern coasts of Central America, or multiple migration waves without population admixture across Central America.
Maxillofacial and dental arch dimensions of the Bolivian Aymara population are age and sex dependent. Interpopulational comparisons reveal these dimensions to differ from those seen in Aleuts, Australian aborigines, and Swedes, but to be similar to those of the indigenous Taiwanese. Finally, these dimensions are not the same in Aymara of unmixed ancestry, and Mestizos residing in the same villages.
The beta2-adrenergic receptor is involved in the control of numerous physiological processes and, as the primary catecholamine receptor in the lungs, is of particular importance in the regulation of pulmonary function. There are several polymorphic loci in the beta2-adrenergic receptor gene that have alleles that alter receptor function, including two (A/G46, G/C79) that increase agonist sensitivity. As such a phenotype may increase vaso and bronchial dilation, thereby facilitating air and blood flow through the lungs, we hypothesized that selection may have favoured these alleles in high altitude populations as part of an adaptive strategy to deal with the hypoxic conditions characteristic of such environments. We tested this hypothesis by determining the allele frequencies for these two polymorphisms, as well one additional missense mutation (C/T491) and two silent mutations (G/A252 and C/A523) in 63 Quechua speaking natives from communities located between 3200 and 4200 m on the Peruvian altiplano. These frequencies were compared with those of two lowland populations, one native American (Na-Dene from the west coast of Canada) and one Caucasian of Western European descent. The Quechua manifest many of the pulmonary characteristics of high altitude populations and differences in allele frequencies between the Quechua and lowlanders could be indicative of a selective advantage conferred by certain genotypes in high altitude environments. Allele frequencies varied between populations at some loci and patterns of linkage disequilibrium differed between the old-world and new-world samples; however, as these populations are not closely related, significant variation would be expected due to stochastic effects alone. Neither of the alleles associated with increased receptor sensitivity (A46, G79) was significantly over-represented in the Quechua compared with either lowland group. The Quechua were monomorphic for the C allele at base 79. This variant has been associated with body mass index; however no clearly defined metabolic phenotype has been established. In addition, we sequenced the coding region of the gene in three unrelated Quechua to determine if there were any other polymorphisms common in this population. None were detected.