Descent measures for two loci with some applications

For any four genes, two at each of two loci, in a population, a 15 component descent measure has been introduced. These components are the probabilities of the 15 possible arrangements on a set of initial gametes of those genes of which the four of interest are copies. Since identity by descent of genes is equivalent to their being copies of a single gene on an initial gamete, descent measures have inbreeding coefficients as special cases. The individual descent measure, defined for four genes on two uniting gametes can be evaluated for any pedigree by means of an algorithm developed here. If initial gametic frequencies are specified, descent measures allow genotypic frequencies and disequilibria functions at one and two loci to be found. The procedures are illustrated for selfing and for sib mating. Several applications of the descent measures are discussed.     

The Implications of Marriage Rules and Descent: Categories for Merina Social Structures

Contrary to previous accounts, the Merina have cognatic, endogamous descent categories. As a result of Merina imperialism and French colonialism they are now dispersed all over Madagascar. Those of free descent still prefer to marry endogamously, although embarrassed at the taint of incest attaching to it, and to be buried in the tombs of the original villages around Tananarive which they consider home. The equally numerous population of slave descent has no such ties. They pride themselves on marrying exogamously and establish tombs in the villages where they have settled. The free not only thus maintain attachment to their traditional groupings but derive benefit from them for social and spatial mobility.     

Descent of the hyoid in chimpanzees: evolution of face flattening and speech

The human supralaryngeal vocal tract develops to form a unique two-tube configuration with equally long horizontal and vertical cavities. This anatomy contributes greatly to the morphological foundations of human speech. It is believed to depend on the reduced growth of the palate and on the developmental descent of the larynx relative to the palate. Anatomically, the descent of the larynx is accomplished through both the descent of the laryngeal skeleton relative to the hyoid and the descent of the hyoid relative to the palate. We have studied the development of three living chimpanzees using magnetic resonance imaging. Our previous study showed that, as in humans, chimpanzees show rapid laryngeal descent, with changes in the relative proportion of the vocal tract during early infancy. However, this is not accompanied by the descent of the hyoid relative to the palate, although it is achieved with the descent of the laryngeal skeleton relative to the hyoid. Here, we show that subsequently the chimpanzee hyoid also descends to maintain the rapid descent of the larynx, similarly to humans. We argue that the descent of the larynx probably evolved in a common ancestor of extant hominoids, originally to confer an advantage via a function unrelated to speech. Thus, the descent of the larynx per se is not unique to humans, and facial flattening was probably the major factor that paved the way for speech in the human lineage.     

Identity by Descent in Island-Mainland Populations

A new model is presented for the genetic structure among a collection of island populations, with fluctuating population sizes and continuous overlapping generations, using a stochastic birth, death and immigration (BDI) process. Immigrants enter each island from a large mainland population, with constant gene frequencies, according to a Poisson process. The average probability of identity by descent (IBD) for two haploid individuals randomly selected from an island population is f(0) = (f(1) + λ)/( + λ), where f(1) is the probability of IBD for two randomly selected immigrants, λ is the birth-rate for each individual, and is the arrival rate of immigrants into each island. The value of f(0) is independent of the death process, time and N. The expected level of genetic differentiation among island populations is F(ST) = (1 - 1/n)λ/( + λ), where n is the total number of islands receiving immigrants. Because f(0) and F(ST) are independent of the death process, for a BDI model, the population genetic structure for several general demographic situations may be examined using our equations. These include stochastic exponential, or logistic (regulated by death rate) growth within islands, or a ``source-sink' population structure. Because the expected values of both f(0) and F(ST) are independent of time, these are achieved immediately, for a BDI model, with no need to assume the island populations are at genetic equilibrium.     

Additive Genetic Variation in Schizophrenia Risk Is Shared by Populations of African and European Descent

To investigate the extent to which the proportion of schizophrenia’s additive genetic variation tagged by SNPs is shared by populations of European and African descent, we analyzed the largest combined African descent (AD [n = 2,142]) and European descent (ED [n = 4,990]) schizophrenia case-control genome-wide association study (GWAS) data set available, the Molecular Genetics of Schizophrenia (MGS) data set. We show how a method that uses genomic similarities at measured SNPs to estimate the additive genetic correlation (SNP correlation [SNP-r_g]) between traits can be extended to estimate SNP-r_g for the same trait between ethnicities. We estimated SNP-r_g for schizophrenia between the MGS ED and MGS AD samples to be 0.66 (SE = 0.23), which is significantly different from 0 (p_{(SNP-rg = 0)} = 0.0003), but not 1 (p_{(SNP-rg = 1)} = 0.26). We re-estimated SNP-r_g between an independent ED data set (n = 6,665) and the MGS AD sample to be 0.61 (SE = 0.21, p_{(SNP-rg = 0)} = 0.0003, p_{(SNP-rg = 1)} = 0.16). These results suggest that many schizophrenia risk alleles are shared across ethnic groups and predate African-European divergence.     

Sentimental Structure: Tsimihety Migration and Descent

Patrilineal descent is deployed by the Tsimihety of Madagascar as a criterion for the definition of sentiments of social identity and adhesion, counter-balancing the dispersal brought about by migration. Patrilineality provides Tsimihety with a rationale for the determination of general rights of access to certain resources, in contrast to other criteria such as cognatic kinship, through which specific rights may be claimed.     

Human Physiological Responses to the G-Load Accompanying the Orbiting and Descent of Soyuz Spacecraft

Data accumulated over 25 years (from 1975 to 2000) on cosmonaut physiological reactions, subjective sensations, and general resistance to G-loads accompanying the orbiting, descent, and landing of Soyuz spacecraft during actual spaceflights are summarized. Materials on short-term (shorter than one month) and long-term (longer than one month) missions in which cosmonauts used or did not use means of preventing microgravity effects during the flight and an anti-G suit (AGS) during descent are analyzed. The physiological reactions of cosmonauts during real spaceflights and terrestrial studies using a centrifuge are compared taking into account cosmonaut ages (from 31 to 55 years). The strain on physiological systems and the reserves of the body upon exposure to +Gxregimens is estimated. A distinct trend toward a lower resistance to descent G-load (without an AGS) with an increase in the time spent in microgravity is found even in the cases when means of prevention of microgravity effects were used. The necessity of using an AGS during descent, irrespective of the flight duration, is demonstrated. The results obtained enable the resistance of cosmonauts to standard G-load conditions during real spaceflights to be predicted.     

Descent Group Composition and Population Pressure in a Fringe Enga Clan, Papua New Guinea

Genealogical data, land clearance patterns, and garden inheritance histories from a patrilineal clan in the Highlands of Papua New Guinea are used to reconstruct population size and agrarian resources for the descent group over a period of 170 years. The resulting analysis reveals a strong relationship between fluctuations in population pressure on agrarian resources and changes in the composition of social groups that in turn accelerates change, then regulates it. Two quantitative relationships show that numbers of outsiders incorporated into the group and their kinship distance both covary closely with pressure on land as measured by an occupational density index.     

Descent graphs in pedigree analysis: applications to haplotyping, location scores, and marker-sharing statistics.

The introduction of stochastic methods in pedigree analysis has enabled geneticists to tackle computations intractable by standard deterministic methods. Until now these stochastic techniques have worked by running a Markov chain on the set of genetic descent states of a pedigree. Each descent state specifies the paths of gene flow in the pedigree and the founder alleles dropped down each path. The current paper follows up on a suggestion by Elizabeth Thompson that genetic descent graphs offer a more appropriate space for executing a Markov chain. A descent graph specifies the paths of gene flow but not the particular founder alleles traveling down the paths. This paper explores algorithms for implementing Thompson's suggestion for codominant markers in the context of automatic haplotyping, estimating location scores, and computing gene-clustering statistics for robust linkage analysis. Realistic numerical examples demonstrate the feasibility of the algorithms.     

Inter-Segmental Coordination Pattern in Patients with Anterior Cruciate Ligament Deficiency during a Single-Step Descent

Anterior cruciate ligament injury is a debilitating pathology which may alter lower limb coordination pattern in both intact and affected lower extremities during activities of daily living. Emerging evidence supports the notion that kinematic variables may not be a good indicator to differentiate patients with anterior cruciate ligament deficiency during step descent task. The aim of the present study was to examine alterations in kinematics as well as coordination patterns and coordination variability of both limbs of these patients during a single step descent task. Continuous relative phase technique was used to measure coordination pattern and coordination variability between a group of anterior cruciate ligament deficient (n = 23) and a healthy control group (n = 23). A third order polynomial Curve fitting was utilized to provide a curve that best fitted to the data points of coordination pattern and coordination variability of the healthy control group. This was considered as a reference to compare to that of patient group using nonlinear regression analysis. The results of the present study demonstrated an altered coordination pattern of the supporting shank-thigh and the stepping foot-shank couplings in anterior cruciate ligament deficient subjects. It was further noticed that there was an increased coordination variability in foot-shank and shank-thigh couplings of both supporting and stepping legs. There was no significant difference in the hip, knee and ankle joints kinematics in either side of these patients. Anterior cruciate ligament deficient individuals showed altered strategies in both intact and affected legs, with increased coordination variability. Kinematic data did not indicate any significant difference between the two groups. It could be concluded that more sophisticated dynamic approach such as continuous relative phase would uncover discrepancies between the healthy and anterior cruciate ligament deficient individuals.     

The genetic or mythical ancestry of descent groups: lessons from the Y chromosome

Traditional societies are often organized into descent groups called "lineages," "clans," and "tribes." Each of these descent groups claims to have a common ancestor, and this ancestry distinguishes the group's members from the rest of the population. To test the hypothesis of common ancestry within these groups, we compared ethnological and genetic data from five Central Asian populations. We show that, although people from the same lineage and clan share generally a recent common ancestor, no such common ancestry is observed at the tribal level. Thus, a tribe might be a conglomerate of clans who subsequently invented a mythical ancestor to strengthen group unity.     

Fasu Solidarity: A Case Study of Kin Networks, Land Tenure, and Oil Extraction in Kutubu, Papua New Guinea

In the Fasu region of Papua New Guinea's fringe highlands, the oil extraction industry has imposed development values and the identification of corporate groups as beneficiary landowners. In response, Fasu males have tightened the boundaries of their agnatic descent groups to become exclusive patriunits. Cash royalties are incorporated into sociopolitical exchange, so the formation of exclusive kin groups allows males to expand social networks to other regions, whilst ensuring continuing wealth for future generations. Consequently, males are becoming isolated from pre–oil exchange networks, and females are becoming isolated within villages. In this article, I map the transition of Fasu kin networks from an ideology of descent to a dogma of descent and patrilineal solidarity, locating the transition in the symbolic codes that inform kin categories. I aim to highlight some consequences of "development" and to advance knowledge on the link between kinship and descent in a postcolonial, industry-dominated Papua New Guinea.     

Descent, Affinity, and Ritual Relations in Eastern Turkey

The available anthropological literature on ritual co-parenthood focuses mainly on the Christian world. This paper discusses and analyzes the structure and functions of kivrelik , a form of ritual co-parenthood established through the Islamic ritual of circumcision and practiced in Eastern Turkey. It explains howw kivrelik can function as either an intra-group or an inter-group integrative mechanism, or as a device to extend one's personal social network. It also discusses the complementary and supplemental uses of ritual kinship, descent, and affinity.     

Descent of the testis in the fetal calf. A summary of the anatomy and process

The descent of the testis in the fetal calf is reviewed, and the role in that process of the swelling reaction of the gubernaculum testis is discussed. The testes of 30 Dutch Friesian fetuses were examined by dissection and light microscopy of sections prepared from chemically and frozen-fixed specimens. The gubernaculum remains unattached to the scrotal fasciae until descent is completed. Shortening of the intra-abdominal gubernaculum and displacement of the testis begins at fetal week 11; the swelling reaction of the gubernaculum occurs between weeks 14 and 15. The testis is at the deep inguinal ring by week 15, and by week 20 it is in the scrotal position and the gubernaculum has regressed. It is proposed that the swelling of the gubernaculum dilates the vaginal ring and enlarges the inguinal canal. The clinical importance of these anatomical relationships and changes is discussed.     

Directed Aerial Descent Behavior in African Canopy Ants (Hymenoptera: Formicidae)

Several species of neotropical ants direct their aerial descent toward tree trunks during a fall from the forest canopy. The primary goal of this study was to determine if afrotropical arboreal ants exhibit similar gliding behavior. Ants were collected from nine tree crowns in late secondary forest at a hydrocarbon extraction site near Gamba, Gabon. Of the 32 species tested, the behavior was observed in five Cataulacus spp. and three Camponotus spp., making this the first report of gliding in African ants. Aerial glide performance (horizontal distance traveled per unit vertical drop distance) decreased with increasing body size among species and among individuals of Cataulacus erinaceus. Characteristics of directed descent behavior in C. erinaceous were very similar to those of the neotropical ant Cephalotes atratus.     

The Noble House in Colonial Puebla, Mexico: Descent, Inheritance, and the Nahua Tradition

Claude Lévi-Strauss's concept of the 'house" has proven to be a viable alternative to traditional lineage theory in the study of many societies, and this paper applies the house concept to a Mesoamencan case. The teccalli , or noble house, was an important aspect of Nahua (Aztec) sociopolitical organization in prchispanic and early colonial central Mexico, particularly in the Puebla-Tlaxcala Valley. It is often characterized as a lineage with rights in land and commoner labor, yet the nature of descent, succession, and inheritance are little understood. Late colonial wills and lawsuits from the (formerly) Nahua community of Santiago Tecali in the Puebla-Tlaxcala Valley provide valuable insights into these matters that can also help us to understand earlier periods. It is argued that the Nahua noble house can be better understood as a house than as a lineage, [house, kinship, inheritance, Nahuas, Mesoamerica]     

Statistical Methods for Linkage Analysis of Complex Traits from High-Resolution Maps of Identity by Descent

A multilocus model for complex traits is described that generalizes the additive and multiplicative models and hence allows simultaneously for both heterogeneity and gene interaction (epistasis). Statistical methods of linkage analysis are discussed under the assumption that identity by descent data from a dense set of polymorphic markers are available. Three methods, single locus search, simultaneous search and conditional search, are described and compared.     

Effect of Er,Cr:YSGG Laser at Different Output Powers on the Micromorphology and the Bond Property of Non-Carious Sclerotic Dentin to Resin Composites

Background

The objective of this study was to investigate the influence of Er,Cr:YSGG laser irradiated at different powers on the micromorphology and the bonding property of non-carious sclerotic dentin to resin composites.

Methods

Two hundred bovine incisors characterized by non-carious sclerotic dentin were selected, and the seventy-two teeth of which for surface morphological analysis were divided into nine groups according to various treatments (A: the control group, B: only treated with the adhesive Adper Easy One, C: diamond bur polishing followed by Adper Easy One, D-I: Er,Cr:YSGG laser irradiating at 1W, 2W, 3W, 4W, 5W, 6W output power, respectively, followed by Adper Easy One). The surface roughness values were measured by the non-contact three-dimensional morphology scanner, then the surface micromorphologies of surfaces in all groups were assessed by scanning electron microscopy (SEM); meanwhile, Image Pro-Plus 6.0 software was used to measure the relative percentage of open tubules on SEM images. The rest, one hundred twenty-eight teeth for bond strength test, were divided into eight groups according to the different treatments (A: only treated with the adhesive Adper Easy One, B: diamond bur polishing followed by the above adhesive, C-H: Er,Cr:YSGG laser irradiating at 1 W, 2 W, 3 W, 4 W, 5 W, 6 W output power, respectively, followed by the above adhesive), and each group was subsequently divided into two subgroups according to whether aging is performed (immediately tested and after thermocycling). Micro-shear bond strength test was used to evaluate the bond strength.

Results

The 4W laser group showed the highest roughness value (30.84±1.93μm), which was statistically higher than the control group and the diamond bur groups (p<0.05). The mean percentages ((27.8±1.8)%, (28.0±2.2)%, (30.0±1.9)%) of open tubules area in the 4W, 5W, 6W group were higher than other groups (p<0.05). The 4W laser group showed the highest micro-shear bond strength not only in immediately tested (17.60±2.55 PMa) but after thermocycling (14.35±2.08MPa).

Conclusion

The Er,Cr:YSGG laser at 4W power can effectively improve the bonding property between non-carious sclerotic dentin and resin composites by increasing the roughness and mean percentage area of open tubules.     

Determinants of Adherence to Treatment in Hypertensive Patients of African Descent and the Role of Culturally Appropriate Education

Background

In Western countries, better knowledge about patient-related determinants of treatment adherence (medication and lifestyle) is needed to improve treatment adherence and outcomes among hypertensive ethnic minority patients of African descent.

Objective

To identify patient-related determinants of adherence to lifestyle and medication recommendations among hypertensive African Surinamese and Ghanaian patients with suboptimal treatment results (SBP≥140) living in the Netherlands and how culturally appropriate hypertension education (CAHE) influenced those determinants.

Methods

This study analysed data of 139 patients who participated in the CAHE trial. Univariate logistic regression analysis was used to measure the association between patient-related determinants (medication self-efficacy, beliefs about medication and hypertension, social support, and satisfaction with care) and treatment adherence. We also tested whether CAHE influenced the determinants.

Results

Medication self-efficacy and social support were associated with medication adherence at baseline. At six months, more medication self-efficacy and fewer concerns about medication use were associated with improved medication adherence. Self-efficacy was also associated with adherence to lifestyle recommendations at baseline. CAHE influenced patients’ illness perceptions by creating more understanding of hypertension, its chronic character, and more concerns about the associated risks.

Conclusion

In this high-risk population, health care providers can support medication adherence by paying attention to patients’ medication self-efficacy, the concerns they may have about medication use and patients’ perceptions on hypertension. The CAHE intervention improved patients’ perception on hypertension.     

Where Have All Their Lineages Gone? Cattle and Descent Among the Nuer

Evans-Pritchard's The Nuer not only served as the paradigm of "segmentary lineage systems," but it also inspired a wide range of ethnographic literature which contributed to the elaboration of "descent theory." The Nuer ethnography was reanalyzed many times and most recently it was declared that the "segmentary lineage system" constituted a "representational model" only, quite different from the actors' "operational rules" (Holy 1979a). Despite the remarkable insight that it proved in the formation of Nuer local groups and the mechanics of Nuer politics, Holy's analysis falls short of a satisfactory reinterpretation of the Nuer polity for those interested in comparison because it restricted itself to local groups and failed to tackle the Nuer concepts of buth, thok dwiel and mar, central to Evans-Pritchard's interpretation. By relegating lineages to the status of "representation," Holy further obscures the course of comparative analysis since he does not provide any criterion to discover when lineages belong to the "representational" or the "operational" levels. Using a different conceptual framework, it is demonstrated that the groups which Evans-Prit chard interpreted as lineages are not "representations" but are in fact defined around cattle. It is concluded that the Nuer simply did not have any lineages, segmentary or not.