Questions of khoesan continuity: Dental affinities among the indigenous holocene peoples of South Africa

The present report follows up on the findings of previous research, including recent bioarchaeological study of well‐dated Khoesan skeletal remains, that posits long term biological continuity among the indigenous peoples of South Africa after the Pleistocene. The Arizona State University Dental Anthropology System was used to record key crown, root, and intraoral osseous nonmetric traits in six early‐through‐late Holocene samples from the Cape coasts. Based on these data, phenetic affinities and an identification of traits most important in driving intersample variation were determined using principal components analysis and the mean measure of divergence distance statistic. To expand biological affinity comparisons into more recent times, and thus preliminarily assess the dental impact of disproportionate non‐Khoesan gene flow into local peoples, dental data from historic Khoekhoe and San were also included. Results from the prehistoric comparisons are supportive of population continuity, though a sample from Matjes River Rockshelter exhibits slight phenetic distance from other early samples. This and some insignificant regional divergence among these coastal samples may be related to environmental and cultural factors that drove low‐level reproductive isolation. Finally, a close affinity of historic San to all samples, and a significant difference of Khoekhoe from most early samples is reflective of documented population history following immigration of Bantu‐speakers and, later, Europeans into South Africa. Am J Phys Anthropol 155:33–44, 2014. © 2014 Wiley Periodicals, Inc.     

Hypoplastic area method for analyzing dental enamel hypoplasia

Most analyses of dental enamel hypoplasia compare frequencies of disturbed tooth types, which do not account for variability in the area of affected enamel. An alternate methodology, hypoplastic area, is presented here that accounts for this variability by combining acute and continuous enamel hypoplasia into an interval-level variable. The method compares samples based on individuals, by multiple tooth type variables, or by a single value rather than by tooth types. Use of the hypoplastic area method is illustrated by analyzing human skeletal dentitions in three archaeological samples: Meroitic Nubians from Semna South, Sudan; Anasazi from Navajo Reservoir, New Mexico; and Mogollon from Grasshopper Pueblo, Arizona. Both univariate and multivariate statistical tests are employed to assess variation in defects between individuals and samples. By incorporating measurements of continuous defects, the hypoplastic area method provides information beyond that of frequency data in comparing levels of stress. Flexibility of the method is also discussed. © 1995 Wiley-Liss, Inc.     

Dental caries in wild primates: Interproximal cavities on anterior teeth

Dental caries has been reported in a variety of primates, although it is still considered rare in wild populations. In this study, 11 catarrhine primate taxa (n = 339 individuals; 7946 teeth) were studied for the presence of caries. A differential diagnosis of lesions in interproximal regions of anterior teeth was undertaken, since they had been previously described as both carious and non-carious in origin. Each permanent tooth was examined macroscopically, with severity and position of lesions recorded. Two specimens were examined further, using micro-CT scans to assess demineralization. Differential diagnosis confirmed the cariogenic nature of interproximal cavities on anterior teeth (ICATs). Overall results show 3.3% of all teeth (i.e., anterior and posterior teeth combined) were carious (n = 262), with prevalence varying among species from 0% to >7% of teeth affected. Those with the highest prevalence of ICATs include Pan troglodytes verus (9.8% of anterior teeth), Gorilla gorilla gorilla (2.6%), Cercopithecus denti (22.4%), Presbytis femoralis (19.5%), and Cercopithecus mitis (18.3%). ICATs make up 87.9% of carious lesions on anterior teeth. These results likely reflect dietary and food processing differences among species, but also between the sexes (e.g., 9.3% of all female P. troglodytes verus teeth were carious vs. 1.8% in males). Processing cariogenic fruits and seeds with the anterior dentition (e.g., wadging) likely contributes to ICAT formation. Further research is needed in living primate populations to ascertain behavioral/dietary influences on caries occurrence. Given the presence of ICATs in frugivorous primates, their diagnosis in archaeological and paleontological specimens may shed light on diet and food processing behaviors in fossil primates.     

Quantifying calculus: a suggested new approach for recording an important indicator of diet and dental health.

This paper describes a quantitative approach to the assessment of dental calculus in human archaeological skeletal samples. The approach combines the ranked calculus scoring method described by Buikstra and Ubelaker [1994. Arkansas Archeological Survey Research Series, Arkansas Archeological Survey, Fayetteville, Arkansas] and a modified Simplified Calculus Index, utilized by dental clinicians. We recorded amounts of calculus on the buccal, lingual, and interproximal surface of all extant teeth, and generated an index for the maxillary posterior dentition, maxillary anterior dentition, mandibular posterior dentition, and mandibular anterior dentition for three skeletal samples. They include 145 Egyptian Predynastic individuals from the site of Hierakonpolis, 104 Predynastic individuals from Naqada, Egypt, and 101 Meroitic Nubians from Semna South, present-day Sudan. Mann-Whitney U tests were used to analyze differences between the sexes and among age groups at each site. The results demonstrate that the calculus indices more effectively reveal trends and differences in calculus severity than frequency data can alone. For example, at Hierakonpolis, males (18-35 years) had significantly more calculus in the maxillary posterior dentition than females, while females (50+ years) had significantly more calculus in the maxillary posterior teeth. Frequency data merely showed that 94% of both males and females had calculus. The use of calculus indices can reveal how quickly calculus accumulates with age within the dental arcade and within a sample. Moreover, better understanding of the severity and location of calculus can improve a researcher's knowledge regarding the effect of calculus on dental pathologies, such as carious lesions and periodontal disease.     

An effect of avian hereditary muscular dystrophy on the reaction of troponin-C with its antibody

Antibody prepared against troponin-C, the calcium binding component of the troponin complex, was reacted with I band segments, and the distribution of antibody binding was assessed by immuno-electron microscopy. The I segments were isolated from glycerinated pectoral muscle which was prepared from normal adult chickens and from dystrophic chickens of strain 308. The antibody was deposited at 384 Å ± 7 Å intervals along the thin filaments of the normal muscle. In contrast to the normal controls the dystrophic muscle did not exhibit a distinct periodicity when reacted with anti-troponin-C. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate revealed that although protein bands corresponding to troponin-C could be observed in the gels of the dystrophic preparations, the troponin-C band had migrated slower than that from normal thin filaments. It is concluded that avian muscular dystrophy produces an alteration of the structure of troponin-C resulting in (1) an inability of the protein to combine with its specific antibody and (2) a change in its electrophoretic behavior.     

Immunocytochemical localization of fibronectin in human fibroblast cultures using a cell surface replica technique

The pericellular fibronectin-containing matrices of human foreskin fibroblasts cultured in ascorbate-supplemented medium were examined using surface replicas. An extensive filamentous network is present over and between adjacent cells, with a considerable amount at points of cell-to-cell contact. Indirect immunocytochemical localization of the distribution of fibronectin and procollagen type III within the matrix was done using the peroxidase-antiperoxidase (PAP) sandwich technique. The PAP molecule with the surrounding diaminobenzidine reaction product appears as a globular particle of approximately 39 nm in surface replicas. The apparent size of the marker was larger (60-80 nm) when bound to pericellular fibronectin, due presumably to the binding of more than one PAP complex to each fibronectin molecule. The immunocytochemical data suggest that fibronectin is a component of most, if not all, matrix fibrils. Some of the smallest filaments of the matrix (5-10 nm) exhibit a periodic, beaded appearance, with a repeat distance of approximately 70-100 nm. After either anti-fibronectin or anti-procollagen type III labeling, the filaments were decorated at regular 70-100 nm intervals with the globular marker. We suggest that the periodicity may be due to fibronectin molecules bound to collagen microfibrils at regular intervals. Our results demonstrate the usefulness of combined surface replica and immunocytochemical techniques for analysis of matrix components of cultured cells.     

Interactions between tassel seed genes and other sex determining genes in maize

The tassel seed mutations of maize cause sex reversal of the florets of the tassel, such that the normally staminate florets develop pistils. Although these mutations have been recognized for many years, little is known about how they act. We have tested the hypothesis that the tassel seed genes interact directly with each other and with other genes controlling sex determination in a single genetic pathway by the construction and analysis of double mutants. On the basis of the phenotypes of the double mutants, the tassel seed mutations were placed into two groups: ts1, ts2, Ts5 and ts4, Ts6. Both groups of tassel seed mutations were additive with the masculinizing mutation dwarf, indicating independent modes of action. Interactions of tassel seed mutations with silkless varied, allowing the ordering of the action of the various tassel seed mutations relative to silkless. Both groups of tassel seed mutations were epistatic with regard to sex expression to mutations that alter both architecture of the plant and distribution of male and female florets, Teopod 1, terminal ear, and teosinte branched. Thus, there are at least two separate genetic pathways that control the sex of florets in maize tassels. In addition, analysis of double mutants revealec that all tassel seed genes tested play a role in the regulation of flower morphogenesis as well as pistil suppression. © 1994 Wiley-Liss, Inc.     

A new simulation of cyanobacterial underwater movement (SCUM'96)

This paper reports the further development of a model simulatingthe movement and growth of freshwater cyanobacteria. Photasyntheticproduction of carbohydrate is calculated under different environmentalconditions Carbohydrate is then allocated to growth and cellmaintenance with excess production forming cellular ballast.From this density change is calculated and vertical migrationsimulated within the water column. The approach taken is conceptuallydifferent from other recent models. Turbulent lake mixing isincluded to study the physiological responses of cyanobacteriato environmental variability.