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PubMed1982

Migration and genetic infrastructure of the Central American Guaymi and their affinities with other tribal groups.

New genetic data on 40 red cell enzymes, antigenic blood groups, and serum proteins representing 42 separate loci, are reported for two Guaymi communities in Southeastern Costa Rica. These two settlements, Limoncito and Abrojo, are of recent origin, having been established by Panamanian migrants in the last 50 years. Detailed data on the provenance of these migrants permits an analysis of how these settlement patterns differ from those typical of less acculturated Amerindians from the lowlands of South America. The genetic compositions of these two communities are compared with those of previous Panamanian Guaymi samples, and several points are established: (1) One of the localities, Limoncito, contains families from both Guaymi dialect groups (eastern and western), and the allelic frequencies are intermediate between those of the dialect groups. (2) The other settlement, Abrojo, is quite similar to the western Guaymi, as expected from historical reconstruction of its antecedents. (3) In general, the degree of infratribal genetic diversity is less than that found in lowland South American tribes, and the difference may be due to a diffuse settlement pattern among the Guaymi. (4) The Guaymi are also compared genetically with other tribes in low Central America and northern South America, and appear to be similar to their immediate Chibcha neighbors to the east and west. The implications of a pair of "private polymorphisms" are discussed in the context of the time of dialectic and tribal divergence in this zone.

Alleles↗

PubMed1985

Dramatic founder effects in Amerindian mitochondrial DNAs.

Southwestern American Indian (Amerindian) mitochondrial DNAs (mtDNAs) were analyzed with restriction endonucleases and found to contain Asian restriction fragment length polymorphisms (RFLPs) but at frequencies very different from those found in Asia. One rare Asian HincII RFLP was found in 40% of the Amerindians. Several mtDNAs were discovered which have not yet been observed on other continents and different tribes were found to have distinctive mtDNAs. Since the mtDNA is inherited exclusively through the maternal lineage, these results suggest that Amerindian tribes were founded by small numbers of female lineages and that new mutations have been fixed in these lineages since their separation from Asia.

Asia↗

PubMed1986

Gene flow across tribal barriers and its effect among the Amazonian Içana river Indians.

Demographic information was obtained from 622 individuals of five communities of primarily Baniwa Amerindians living near the Içana river in Brazil. Four of these populations, plus another from the same area, were also studied genetically. The latter investigation included the blood and, in some cases, saliva of 531 subjects, variously tested in relation to 40 genetic systems. Demographically these groups are characterized by young age, high intertribal admixture, low non-Indian admixture, high exogamy but low marital distance and high inbreeding, high fertility but low variance in offspring number, and relatively low mortality. Their gene pool shows a peptidase B variant (PEPB2BAN1) and "private" polymorphism of carbonic anhydrase2 (CA2BAN1) until now observed only among them. Other distinctive characteristics are the low frequencies of LNS (0.08), LNs (0.09), RZ (0.01), RO or r(0.02), ACPA (0.08), GALTD (0.01), and the relatively high prevalences of Gm (0.05) and Gc1 (0.82). TfDchi occurs with a low prevalence (0.01). Genetic distance analysis reveals that the one Baniwa sample by history comprised of minimally admixed individuals is quite similar genetically to the Wapishana, another Arawak-speaking tribe some 900 km to the east, and that the genetic distances between the Baniwa communities reflect the amount of historical admixture in a way that indicates which should be excluded from considerations of intertribal genetic distances. Finally, the genetic relation of the Baniwa to the nearby tribes is examined.

Adolescent↗

PubMed1987

Blood types of the native Americans of Oklahoma.

Large numbers of Indians from Oklahoma were screened for a variety of red cell antigens. Sufficient numbers of Cherokees, Creeks, and Choctaws were studied to calculate gene frequencies. These tribes originated in the Southeastern United States and were forcibly moved to Oklahoma. The Creeks and Choctaws have not been studied previously. A small number of Cherokees remained in North Carolina, and their blood types have been reported. The blood types of the Oklahoma Cherokees are quite similar to those observed there but one important difference was discovered. The data previously reported concerning the Eastern Cherokees revealed the absence of the Dia antigen. The present study found that the Oklahoma Cherokees do have the Dia antigen, although in a lower percentage than the other southeastern tribes. The Creeks and Choctaws share a linguistic heritage as well as having similar red cell phenotypes.

Blood Group Antigens↗

PubMed1992

Effects of demographic and ethnohistorical factors on average heterozygosities of South Amerindians.

Recent investigations have shown that average within-Tupi genetic distances differ from within-Carib distances, which is possibly due to differences in effective size of the populations belonging to these two linguistic stocks of South American tribes. The aim of this paper is to verify the influence of demographic factors and of interpopulation contacts on the degree of intragroup genetic variability of 18 South American native groups (eight Carib, seven Tupi, and three Gê). The mean per locus per individual heterozygosity (Hm) was studied for seven polymorphic systems and the distance from the centroid rii on Hm was evaluated with regression analysis according to Harpending and Ward's model. Data on intergroup contacts among the populations since the end of the eighteenth century were collected from an extensive review of the ethnohistorical literature. The level of Hm of the three linguistic stocks did not differ, which suggests a homogeneous within-group variation for these groups. In addition, there was no association between gene diversity and population size. On the other hand, demographic size correlated with rii, which suggest that gene frequencies in groups of larger populations more closely resemble the average gene frequencies of native South Americans. Values of rii differed between the stocks, and the average distance from the centroid of the Carib was about 2.6 times greater than that of the Tupi, in accordance with previous genetic distance analysis. It should also be emphasized that there was an important correlation between mean heterozygosity and the degree of historical intertribal contacts. This constitutes a particularly significant finding, suggesting the basic role of intertribal gene flow of the past two centuries on the level of present genetic variability of South American tribes.

Gene Frequency↗

PubMed1992

Dietary and dental adaptations in the Pitheciinae.

Since Mivart (1865), Cacajao, Chiropotes, and Pithecia have been grouped into a single taxon, which he called the subfamily Pitheciinae but which I, following Rosenberger (this issue), refer to as the living members of the tribe Pitheciini. While few today doubt the association of these three living genera, not all would place them together with Aotus and Callicebus in the subfamily Pitheciinae. This is an attempt to sort out the behavioral and morphological features of feeding and dental morphology in these taxa. Extant members of the tribe Pitheciini are adapted for sclerocarpic foraging, morphological evidence for which is found in the fossils of Soriacebus and Cebupithecia. Sclerocarpic foraging in living pitheciins is a two-stage process of seed predation involving 1) specialized features of the anterior dentition that allow removal of a hard pericarp that protects a seed or seeds, followed by 2) mastication by the posterior dentition having low cusp relief to triturate nutritious seeds of a relatively soft and uniformly pliable consistency. The dentitions of fossil pitheciins, Soriacebus and Cebupithecia, demonstrate that the hypertrophy of lower incisors plus the robustness and flaring of the canine precede development of low cusp relief on molars and premolars in the evolution of morphological features associated with sclerocarpic foraging. Features of sclerocarpic foraging are found less uniformly in the other two pitheciines, Callicebus and Aotus.

Adaptation, Physiological↗

PubMed2006

Inbreeding and surnames: a projection into Easter Island's past.

The population of Easter Island is one of the most interesting extant human communities due to its unique demographic history, its geographic isolation, and the development of an incomparable culture characterized by the towering "Moais" and its enigmatic writing. Following the colonization of its population by Polynesians from the Mangarevan Islands in the 5th century AD, the island remained isolated up until the middle of the 20th century. Under these conditions, with endogamy levels fluctuating between 61.04-96.54% and given such a small population, a high rate of inbreeding, and consequently, an elevated level of genetic relationships would be expected. Using data from church and civil records, we calculated the consanguinity of the population of Rapa Nui. The results of this analysis do not support the hypothesis of a high level of consanguinity (alpha = 0.00028 and F(t) = 0.0007, with F(r) = 0.00586 and F(n) = -0.00519), suggesting instead the existence of a strategy used to avoid marriage between close relatives. To explain these observations, the structure and exchange dynamics of the population were studied in the tribes, known locally as "Mata." The results of this analysis suggest a tendency toward the avoidance of inbreeding within tribes, in order to decrease the rate of endogamy in each group. This is consistent with ethnographic observations from the beginning of the 20th century that support the existence of strict regulations to prevent inbreeding between closely related individuals. Furthermore, we confirm that this situation dates back to a period before the "refounding" of Easter Island. Our results demonstrate that conditions of geographical isolation are not in themselves sufficient to produce an elevated inbreeding coefficient, revealing Easter Island as an interesting example of how cultural rules can shape the genetic structure of a population.

Cluster Analysis↗

PubMed2006

Population origins in Mongolia: genetic structure analysis of ancient and modern DNA.

In the present study, nuclear (autosomal and Y-chromosome short tandem repeats) and mitochondrial (hypervariable region I) ancient DNA data previously obtained from a 2,300-year-old Xiongnu population of the Egyin Gol Valley (south of Lake Baikal in northern Mongolia) (Keyser-Tracqui et al. 2003 Am. J. Hum. Genet. 73:247-260) were compared with data from two contemporary Mongolian populations: one from the same location (Egyin Gol Valley plus a perimeter of less than 100 km around the valley), and one from the whole of Mongolia. The principal objective of this comparative analysis was to assess the likelihood that genetic continuity exists between ancient and present-day Mongolian populations. Since the ancient Xiongnu sample might have been composed of some of the ancestors of the present-day Yakuts, data from a present-day Yakut population, as well as published data from Turkish populations, were also included in the comparative analysis. The main result of our study was the genetic similarity observed among Mongolian samples from different periods and geographic areas. This result supports the hypothesis that the succession over time of different Turkic and Mongolian tribes in the current territory of Mongolia resulted in cultural rather than genetic exchanges. Furthermore, it appears that the Yakuts probably did not find their origin among the Xiongnu tribes, as we previously hypothesized.

Chromosomes, Human, Y↗

PubMed1976

The action of trypsin and chymotrypsin on the reserve proteins of some leguminous seeds.

The action of trypsin on the reserve proteins of the leguminous seeds belonging to Vicieae and Phaseoleae tribes was investicated. The hydrolysis of11S and 7S proteins of Vicieae proceeds relatively fast and some of the proteins are hydrolyzed practically completely. The hydrolysis of most of the investigated reserve proteins of the Phaseoleae tribe proceeds much slower, while that of 7S proteins of four Phaseolus species of American origin stops after the cleavage of only 10-20% of peptide bonds capable of reacting. Analogous results were obtained studying the action of chymotrypsin on a more restricted number of proteins. Both trypsin and chymotrypsin hydrolyze the same parts of Ph. vulgaris 7S protein, splitting off peptides which can be separated on a Sephadex G-50 column. The nonhydrolyzable high molecular weight core has a slightly smaller sedimentation coefficient and a higher elelctrophoretic mobility than the native protein and is able to dimerize at high ionic strength. Urea does not alter the hydrolyzability of the core butt the latter is partially hydrolyzed after the action of urea or guanidine hydrocholoride in the presence of mercaptoethanol.

Chymotrypsin↗

PubMed1984

[Chemotherapeutic mixtures for the selective growth of anaerobes].

In order to find a selective medium for the cultivation of Gram-positive spore-less rods several chemotherapeutics have been tested. By adding of 5 micrograms metronidazol/ml to brain-heart-infusion-supplemented agar as well as by putting metronidazol discs on the agar it became possible to cultivate selective test tribes. Lincomycin (5 micrograms/ml), clindamycin (5 micrograms/ml) and novobiocin (5 micrograms/ml) inhibited almost all the test tribes. Spectinomycin (5 micrograms/ml) and neomycin (5 and 10 micrograms/ml) failed to inhibit. With 100 micrograms neomycin/ml Gram-positive anaerobes were clearly inhibited.

Anti-Bacterial Agents↗

PubMed2003

Diversification of brain and sense organ morphology in Antarctic dragonfishes (Perciformes: Notothenioidei: Bathydraconidae).

In the subzero shelf waters of Antarctica, fishes of the perciform suborder Notothenioidei dominate the fish fauna and constitute an adaptive radiation and a species flock. The 16 species of dragonfishes of the family Bathydraconidae live from surface waters to nearly 3,000 m and have the greatest overall depth range among notothenioid families. We examined the anatomy and histology of the brain, retina, and cephalic lateral line system of nine bathydraconid species representing 8 of the 11 known genera. We evaluate these data against a cladogram identifying three clades in the family. We provide a detailed drawing of the brain and cranial nerves of Gymnodraco acuticeps and Akarotaxis nudiceps. Bathydraconid brain morphology falls into two categories. Brains of most species are similar to those of generalized perciforms and some basal notothenioids (Class I). However, brains of deep-living bathydraconids (members of the tribe Bathydraconini minus Prionodraco) have a reduced telencephalon and tectum that renders the neural axis visible - the stalked brain morphology (Class II). All bathydraconids have duplex (rod and cone) retinae but there is considerable interspecific variation in the ratio of cones:rods and in the number of cells in the internal nuclear layer. Retinal histology reflects habitat depth but is not tightly coupled to phylogeny. Although the deep-living species of Bathydraconini have rod-dominated retinae, the retinae of some sister species are photopic. An expanded cephalic lateral line system is also characteristic of all members of the Bathydraconini as exemplified by Akarotaxis. This morphology includes large lateral line pores, wide membranous canals, hypertrophied canal neuromasts, and large anterodorsal lateral line nerves, eminentia granulares, and crista cerebellares. The saccular otoliths are also enlarged in members of this tribe. Neural diversification among bathydraconids on the Antarctic shelf has not involved the evolution of sensory specialists. Brain and sense organ morphologies do not approach the specialized condition seen in primary deep-sea fishes or even that of some secondary deep-sea fishes including sympatric non-notothenioids such as liparids (snailfishes) and muraenolepidids (eel cods). The brains and sense organs of bathydraconids, including the deep-living species, reflect their heritage as perciform shorefishes.

Anatomy, Comparative↗

PubMed2001

Lifestyles, diets, and Native American exposure factors related to possible lead exposures and toxicity.

Lead exposure is still a national concern, and it is possible that Native Americans who live on reservations and pursue traditional lifestyles may be at higher risk through both their unique exposure profiles and their potentially greater sensitivity. A major component of the exposure assessment is the diet. For tribal members, traditional lifestyles that include native foods, medicines, and traditional practices have evolved and proven to be the most healthful over many thousands of years of coexistence with the environment. However, a completely traditional diet may not be fully available for a variety of reasons; so, one must also consider the adverse health consequences caused by the loss of healthy native foods and medicines, the contamination of remaining native foods, the inability to practice one's religion, and the possibly lower quality of the substitute diet. Health evaluations of lead exposure on reservations should therefore consider at least two types of diets in addition to the typical suburban diet: (a) traditional diets composed of native foods and medicines that would result in increased exposure if the plants and animals are contaminated and (b) disadvantaged or commodity food diets that result in widespread vitamin and mineral deficits of the sort known to increase absorption of and response to lead. Additional exposure to lead might come from reservation housing which is often older, although the prevalence of lead-based paint on reservations is unknown. The degree of physiological response could also be affected by widespread exposures to other neurotoxins (such as mercury and PCBs in fish), underlying disease patterns, and genetics. Although each of these factors is plausible, their prevalence singly or in combination is unknown. Any correlation between these risk factors and blood lead levels on reservations is also unknown. This paper begins to address these gaps by discussing the range of traditional and current diets that may exist among tribes and methods for developing a whole-lifestyle exposure scenario that is appropriate for an individual tribe. Some of the factors discussed in this paper may not apply to the large population of Native Americans who live in urban situations.

Adult↗

PubMed1993

Genetic diversity and phylogenetic relationships between birches and alders using ITS, 18S rRNA and rbcL gene sequences.

The Betuleae is one of the two Betulaceae tribes and contains two genera, the actinorhizal genus Alnus and the nonactinorhizal genus Betula. To elucidate the phylogenetic relationships within the tribe and compare the relative amounts of genetic diversity between the genera Alnus and Betula, rbcL and 18S rRNA gene sequences as well as rDNA internal transcribed spacer (ITS1 and ITS2) sequences were obtained and compared. In rbcL and 18S rRNA, several substitutions were detected between Alnus and Betula but no variation was observed within Alnus. Minimal length variation was observed among ITS sequences. The numbers of substitutions per site for ITS were, on average, close to 10 times those estimated for 18S between Alnus and Betula. In ITS, numbers of substitutions were, on average, more than twice as large between genera than within genera. Phylogenies from ITS sequences were estimated using neighbor-joining analysis of substitution rates, maximum likelihood and parsimony methods. Each of the two genera appeared monophyletic, which was supported by high bootstrap estimates. Relationships among the three sections of Betula analyzed were also better resolved than those among the three subgenera of Alnus analyzed. Phylogenies estimated from ITS sequences suggested a relatively recent diversification of each genus, in agreement with fossil data.

DNA, Ribosomal↗

PubMed1993

A phylogeny of New World Deltocephalus-like leafhopper genera based on mitochondrial 16S ribosomal DNA sequences.

The Deltocephalus-like leafhoppers are a group of grass-feeding insects that share common forms in the male genitalia, chiefly a fused aedeagal-connective structure. The group contains 27 New World genera. The phylogenetic relationships among these genera and other genera in the tribe are unclear because fusion of the aedeagus and connective, although clearly apomorphic, has occurred in both related and unrelated groups. An independent set of characters is required to test the hypothesis that the Deltocephalus-like genera are monophyletic and to derive relationships among these genera. We examined 562 sites in the 3'-end of the mitochondrial 16S ribosomal DNA from 21 species representing 19 New World genera. Eight species in closely related groups or tribes were also analyzed. The region was sequenced directly from PCR-amplified DNA of field-collected and museum-preserved dried specimens. The transversion rate was twice as high as the transition rate; however, 74% of these were adenine-thymine transversions. Analysis of secondary structure indicated that substitution rates were equal in stem and loop forming regions of the processed rRNA. Using either parsimony or distance analysis, derived phylogenies suggested that, with the exception of the genus Cabrulus, the Deltocephalus-like leafhoppers are genera within a monophyletic group.

Animals↗

PubMed1995

DNA evidence on the phylogenetic systematics of New World monkeys: support for the sister-grouping of Cebus and Saimiri from two unlinked nuclear genes.

Previous inferences from epsilon-globin gene sequences on cladistic relationships among the 16 extant genera of Ceboidea (the New World monkeys) were tested by strength of grouping and bootstrap values for the clades in the most parsimonious trees found: for this epsilon data set enlarged with additional Cebus and Saimiri orthologues; for another nuclear DNA sequence data set consisting of IRBP (interstitial retinol-binding protein gene) intron 1 orthologues; and for tandemly combined epsilon and IRBP sequences. Different ceboid species of the same genus always grouped strongly together as demonstrated by results on Cebus (capuchin monkeys), Saimiri (squirrel monkeys), Callicebus (titi monkeys), Aotus (night monkeys), Ateles (spider monkeys), and Alouatta (howler monkeys). Other strong groupings that could be represented as monophyletic taxa in a cladistic classification were: Cebuella (pygmy marmoset) and Callithrix (marmoset) into subtribe Callitrichina; Callitrichina, Callimico (Goeldi's monkey), Leontopithecus (lion tamarin), and Saguinus (tamarin) into subfamily Callitrichinae; Callitrichinae, Aotus, Cebus, and Saimiri into family Cebidae; Cacajao (uakari monkey) and Chiropotes (saki) into subtribe Chiropotina; Chiropotina and Pithecia (bearded saki) into tribe Pitheciini; Pitheciini and Callicebus into subfamily Pitheciinae; Brachyteles (woolly spider monkey), Lagothrix (woolly monkey), and Ateles into tribe Atelini; and Atelini and Alouatta into subfamily Atelinae. In addition the epsilon and IRBP results congruently grouped (but at lesser strengths) Brachyteles and Lagothrix into subtribe Brachytelina within Atelini, and also Cebus and Saimiri into subfamily Cebinae within Cebidae. Because the IRBP results weakly grouped Pitheciinae with Cebidae, whereas the epsilon results weakly grouped Pitheciinae with Atelinae, the present evidence is best represented in an interim cladistic classification of ceboids by dividing the superfamily Ceboidea into three families: Atelidae, Pitheciidae, and Cebidae.

Alouatta↗

PubMed1995

Evolution of NADH dehydrogenase subunit 2 in east African cichlid fish.

The complete sequence (1047 bp) of the mitochondrially encoded ND2 gene was obtained from 31 species of cichlid fishes to investigate the evolutionary history of the species flocks of the East African lakes. The observed pattern of nucleotide substitution in this sequence is typical of mitochondrial genes, showing a high transition bias and rapid mutational saturation, especially at codon positions where base frequencies are unequal. The base composition of the third position of codons is heterogeneous among species, suggesting frequent shifts in the pattern of substitution. Phylogenetic analysis of the sequences shows that the mtDNA variation in Lake Malawi cichlids is nested monophyletically within the range of variation shown by Tanganyikan cichlids. The closest Tanganyikan relatives of the Malawi flock are members of the tribe Tropheini. Classifications based on morphology are generally supported by the mtDNA data, with some significant exceptions in the Tropheini and Lamprologini. Because of an apparently rapid radiation of the Tanganyikan lineages, it is difficult to assess the basal topology of the Tanganyikan radiation at this time. Divergences among tribes are consistent with an intralacustrine radiation within the past 10 million years.

Africa, Eastern↗

PubMed1996

The distribution and phylogenetic significance of a 50-kb chloroplast DNA inversion in the flowering plant family Leguminosae.

Species in 9 of the approximately 650 genera of the flowering plant family Leguminosae are known to possess a large (50-kb) inversion in their chloroplast genomes, relative to the gene order found most commonly among land plants. Putatively basal elements of the family have not been surveyed for the inversion, which is unknown outside the legumes. Using a combination of polymerase chain reaction and restriction-mapping approaches employing primers or hybridization probes flanking inversion endpoints, 132 legume genera were screened for the presence of the inversion. The inversion was found to be absent in all taxa from two of the three subfamilies (Mimosoideae and Caesalpinioideae), whereas the inversion was found to be present in most taxa of the third subfamily (Papilionoideae). Two papilionoid tribes, Swartzieae and Sophoreae, were heterogeneous for the inversion, which is consistent with a number of lines of evidence suggesting the polyphyly of these tribes. The 50-kb inversion appears to be a unique event in the evolution of Leguminosae, providing a synapomorphy for a clade that includes most of the Papilionoideae.

Base Sequence↗

PubMed1996

Molecular phylogeny for marine turtles based on sequences of the ND4-leucine tRNA and control regions of mitochondrial DNA.

Marine turtles are divided into two families, the Dermochelyidae and the Cheloniidae. The majority of species are currently placed within the two tribes of the Cheloniidae, the Chelonini and the Carettini, but debate continues over generic and tribal affinities as well as species boundaries. We used nucleotide sequences (907 bp) from the ND4-LEU tRNA region and the control region (526 bp) of mitochondrial DNA to resolve areas of uncertainty in marine turtle (Chelonioidae) systematics. The ND4-LEU tRNA fragment was more conserved than the fragment from the control region, with sequence divergences ranging from 0.026 to 0.148 and 0.067 to 0.267, respectively. Parsimony analysis based only on the ND4-LEU tRNA data suggests that the hawksbill, Eretmochelys imbricata, lies within the tribe Carettni and is closely related to the genus Caretta, but could not resolve the position of the flatback, Natator depressus. A similar analysis based only on the control region sequence data suggested that N. depressus is affiliated with the Chelonini, but failed to resolve the position of E. imbricata and the loggerhead, Caretta caretta. In contrast to these results, the combination of both data sets with published cytochrome b data produced a phylogeny based on 1924 bp of sequence data which resolves the position of E. imbricata relative to Caretta and Lepidochelys and joins N. depressus as sister to the Carettini. Based on the molecular data, the Chelonini contains the Chelonia species, while the Carettini contains the remaining species of Cheloniidae. The control region sequence divergence between Pacific and Atlantic populations of the leatherback, Dermochelys coriacea, was relatively low (0.0081) when compared with the green turtle, Chelonia mydas (0.071-0.074). Atlantic and Pacific populations of Ch. mydas were found to be paraphyletic with respect to the black turtle, Ch. agassizi, suggesting that the current taxonomic designations within the Pacific Chelonia are questionable. This analysis shows the utility of combining sequence data for different regions of mtDNA that by themselves are insufficient to obtain robust phylogenies.

Animals↗