Mutation rate in the hypervariable VNTR g3 (D7S22) is affected by allele length and a flanking DNA sequence polymorphism near the repeat array.

The hypervariable human minisatellite locus D7S22 (g3) is highly polymorphic. The allelic distribution in D7S22 features a size clustering of the alleles and a comparably low allelic diversity among small alleles. This reduced diversity could reflect a situation where some alleles are less likely to mutate than others. Several factors could explain such an effect, including allele size, variation in repeat composition, and allelic differences in nearby cis-acting elements affecting the mutation rate. We have characterized 40 de novo mutations found on Southern blots in a large amount of paternity-testing material. There is a significant excess of paternal mutations, and small size changes are most frequent. Mutation rate is affected by allele length, with highest rates in larger alleles. Alleles of the family groups with D7S22 mutations and 50 small alleles were analyzed by nucleotide sequencing. Two hundred thirty-six base pairs of the immediate flanking region upstream of the repeat array were PCR amplified and screened for point mutations by DNA sequencing of the PCR products. Two base substitution polymorphisms were identified: one C/G transversion and one A/G transition, 54 bp and 173 bp upstream of the repeat array, respectively. There is a significant association between mutation and occurrence of 54C, while association is not obvious between mutation rate and the 173A/G variants. There is a marked association between different flanking haplotypes and allele size, and within the smallest allele-size group, all alleles had the 54G/173A haplotype. Both allele size and allelic state at site 54 remain associated with mutation rate when the other factor is controlled. Possible mechanisms behind the variation in mutation rate in D7S22 are discussed.     

Avoidant Personality Disorder versus Social Phobia: The Significance of Childhood Neglect

Objectives

Avoidant personality disorder (AvPD) and social phobia (SP) are common disorders both in the community and in clinical settings. Whether the two disorders represent different severity levels of social anxiety disorder is currently in dispute. The relationship between AvPD and SP is probably more complex than previously assumed. Several environmental, temperamental, and constitutional factors may play a role in the etiology of AvPD and SP. Better knowledge about childhood experiences may shed light on similarities and differences between the two disorders. The aim of this study was to compare self-reported childhood experiences in AvPD and SP patients.

Design

This is a cross-sectional multi-site study of 91 adult patients with AvPD and/ or SP. We compared patients with AvPD with and without SP (AvPD group) to patients with SP without AvPD (SP group).

Methods

The patients were examined using structured diagnostic interviews and self-report measures, including Child Trauma Questionnaire, Parental Bonding Instrument, and Adult Temperament Questionnaire.

Results

Both AvPD and SP were associated with negative childhood experiences. AvPD patients reported more severe childhood neglect than patients with SP, most pronounced for physical neglect. The difference between the disorders in neglect remained significant after controlling for temperamental factors and concurrent abuse.

Conclusions

The study indicates that childhood neglect is a risk factor for AvPD and may be one contributing factor to phenomenological differences between AvPD and SP.     

Disentangling Early Stone Age palimpsests: determining the functional independence of hominid- and carnivore-derived portions of archaeofaunas

Determining the extent to which hominid- and carnivore-derived components of fossil bone palimpsests formed independently of each other can provide valuable information to paleoanthropologists interested in reconstructing the foraging adaptations of hominids. Because stone tool cutmarks, hammerstone percussion marks, and carnivore tooth marks are usually only imparted on bone during nutrient extraction from a carcass, these bone surface modifications are particularly amenable to the types of analyses that might meet this goal. This study compares the percentage of limb bone specimens that preserve evidence of both hominid- and carnivore-imparted bone damage from actualistic control samples and several Plio-Pleistocene archaeofaunas, including new data from Swartkrans Member 3 (South Africa). We argue that this procedure, which elucidates the degree of hominid-carnivore independence in assemblage formation, will allow researchers to extract for focused analyses high integrity components (hominid and carnivore) from presumably low integrity sites. Comparisons suggest that the hominid- and carnivore-derived components from sites in Olduvai Gorge Bed II (Tanzania), the ST Site Complex at Peninj (Tanzania), and Swartkrans Member 3 formed largely independent of each other, while data from the FLK 22 Zinjanthropus (FLK Zinj) site (Olduvai Gorge Bed I) indicate significant interdependence in assemblage formation. This contrast suggests that some Early Stone Age assemblages (e.g., the Olduvai Gorge Bed II sites, the Peninj ST Site Complex, and Swartkrans Member 3) are probably more useful than others (e.g., FLK Zinj) for assessing the maximal carcass-acquiring abilities of early hominids; in such assemblages as those in the former set, sole hominid-contribution is more confidently discerned and isolated for analysis than in assemblages such as FLK Zinj.     

The anonymous RFLP locus D1S2 is close to PGM1 on chromosome 1

D1S2 was one of the first restriction fragment length polymorphisms (RFLPs) assigned to chromosome 1, but its regional location was unknown. In this paper we present data that place this RFLP into both the genetic map and the physical-cytogenetic map. Linkage data maps D1S2 7 cM from PGM1, which is localized to the middle of the short arm at 1p22.1. Southern blot analysis of DNA samples from somatic cell hybrids containing parts of chromosome 1 maps D1S2 proximal to 1p32 and distal to PGM1.     

Taphonomic perspectives on hominid site use and foraging strategies during Bed II times at Olduvai Gorge, Tanzania

The faunal assemblages excavated by Mary Leakey in Bed II of Olduvai Gorge, Tanzania, have, like the more well-known Bed I assemblages, traditionally been interpreted as the result of hominid butchering activities in the lake margin and riverine settings of the paleo-Olduvai Basin. A reexamination of all of Leakey's Bed I sites has shown that hominids played little or no role in the formation of all but one of those faunal assemblages, a finding that prompted the reanalysis of the Bed II sites presented here. We expand upon a previous taphonomic study that provided systematic data for HWK East Levels 1–2, MNK Main, and BK. In addition to these assemblages, we provide data on HWK East Levels 3–5, FC West, TK, and SHK. Our data contradict previous interpretations of MNK Main as a hominid accumulation but uphold the contention that BK represents a primarily hominid accumulation reflecting early access to carcasses. The small and poorly preserved assemblages from FC West and TK are difficult to link unambiguously to either hominids or carnivores. Site MNK Main and HWK East Levels 3–5 appear to be death arenas where carcasses accumulated via natural deaths and/or serial predation. Site SHK is severely biased by selective retention and therefore little can be said of its formational history. Nevertheless, no hominid modifications were documented in this assemblage. Comparisons with other Olduvai sites indicate a more conspicuous hyena taphonomic signal during Bed II times than Bed I times, which appears to mirror the changing configuration of the large carnivore guild. These findings also beg the question of what activities were being carried out by hominids with the stone tools discarded at these sites. Although it seems clear that hominids were utilizing stone tools to carry out subsistence activities unrelated to carcass butchery, more excavation and techniques such as phytolith analysis should be employed to explore alternative explanations.     

Cannibalism and protective behavior of eggs in Arctic charr (Salvelinus alpinus)

From video recordings of spawning events, we quantified protective and cannibalistic behavior of Arctic charr occurring immediately after spawning. The number of fish cannibalizing on stray eggs was examined regarding (a) whether more than one male shed milt during the spawning event, that is, whether sperm competition occurred, (b) whether the sperm competition included few or many males, that is, the intensity of sperm competition, and (c) the density of fish at the spawning site. Response behavior toward egg cannibalism was also examined among females and dominant males in order to determine any parental investment toward protecting the eggs after spawning. Cannibalistic behavior was seen in almost 50% of the spawnings, and the multiple spawning events showed the highest numbers of fish cannibalizing on eggs. Both the number of males releasing milt and the number of fish approaching the spawning site were positively correlated with egg cannibalism. Sperm competition was, however, not a prerequisite for egg cannibalism. Although we also observed partial filial cannibalism, protective behavior of eggs was seen both among dominant males and females, suggesting that charr actually conduct parental care.     

Bifidobacterial Succession and Correlation Networks in a Large Unselected Cohort of Mothers and Their Children

Bifidobacteria are a major microbial component of infant gut microbiota, which is believed to promote health benefits for the host and stimulate maturation of the immune system. Despite their perceived importance, very little is known about the natural development of and possible correlations between bifidobacteria in human populations. To address this knowledge gap, we analyzed stool samples from a randomly selected healthy cohort of 87 infants and their mothers with >90% of vaginal delivery and nearly 100% breast-feeding at 4 months. Fecal material was sampled during pregnancy, at 3 and 10 days, at 4 months, and at 1 and 2 years after birth. Stool samples were predicted to be rich in the species Bifidobacterium adolescentis, B. bifidum, B. dentium, B. breve, and B. longum. Due to high variation, we did not identify a clear age-related structure at the individual level. Within the population as a whole, however, there were clear age-related successions. Negative correlations between the B. longum group and B. adolescentis were detected in adults and in 1- and 2-year-old children, whereas negative correlations between B. longum and B. breve were characteristic for newborns and 4-month-old infants. The highly structured age-related development of and correlation networks between bifidobacterial species during the first 2 years of life mirrors their different or competing nutritional requirements, which in turn may be associated with specific biological functions in the development of healthy gut.