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The population of a Wiltshire village in the nineteenth century: a reconstitution study of Berwick St James, 1841-71.

This paper reports an exploratory reconstruction of the village of Berwick St James in Wiltshire using nominative information from nineteenth-century English censuses and ecclesiastical registers of baptisms, marriages and burials between 1841 and 1871. The data are first described, and a procedure for sorting and linking records from different censuses, and for linking census records to registration records, is outlined. A detailed analysis of population turnover in the village reveals that after 1851 there was a period of heavy net out-migration. Those who left the parish were overwhelmingly young people, and females were more likely to move out than males: almost all the females born in the parish between 1841 and 1851 had moved away by 1871. A consequence of this pattern of out-migration was that by 1871 there was a shortage of females in the marriageable age-groups (15-29 years). It is clear that this method of reconstructing English village populations promises new insights into the demography of rural England in the nineteenth-century, including, in addition to population turnover and migration patterns, such aspects as fertility levels and trends. A number of problems with the technique remain, however, notably our ignorance of the typical length of the period between birth and baptism.

Demography↗

The fate of ingested Brugia pahangi microfilariae in susceptible and refractory strains of Culex pipiens and Aedes aegypti.

The uptake and migration of microfilariae of Brugia pahangi in susceptible and refractory Culex pipiens and Aedes aegypti were compared after membrane-feeding the mosquitoes on infected blood and anti-coagulant. There was no difference between the strains within each species in the pattern of migration, but in C pipiens only 24% of the microfilariae reached the thorax whereas in A. aegypti 73-6% were successful. In both susceptible strains the filariae in the thorax developed normally to maturity, but in both refractory strains almost all filariae died within a few days.

Aedes↗

Patterns of genetic diversity and migration in increasingly fragmented and declining orang-utan (Pongo pygmaeus) populations from Sabah, Malaysia.

We investigated the genetic structure within and among Bornean orang-utans (Pongo pygmaeus) in forest fragments of the Lower Kinabatangan flood plain in Sabah, Malaysia. DNA was extracted from hair and faecal samples for 200 wild individuals collected during boat surveys on the Kinabatangan River. Fourteen microsatellite loci were used to characterize patterns of genetic diversity. We found that genetic diversity was high in the set of samples (mean H(E) = 0.74) and that genetic differentiation was significant between the samples (average F(ST) = 0.04, P < 0.001) with F(ST) values ranging from low (0.01) to moderately large (0.12) values. Pairwise F(ST) values were significantly higher across the Kinabatangan River than between samples from the same river side, thereby confirming the role of the river as a natural barrier to gene flow. The correlation between genetic and geographical distance was tested by means of a series of Mantel tests based on different measures of geographical distance. We used a Bayesian method to estimate immigration rates. The results indicate that migration is unlikely across the river but cannot be completely ruled out because of the limited F(ST) values. Assignment tests confirm the overall picture that gene flow is limited across the river. We found that migration between samples from the same side of the river had a high probability indicating that orang-utans used to move relatively freely between neighbouring areas. This strongly suggests that there is a need to maintain migration between isolated forest fragments. This could be done by restoring forest corridors alongside the river banks and between patches.

Animals↗

Spatial and space-time correlations in systems of subpopulations with stochastic migration.

The great majority of models of the population genetics of subdivided populations have made the simplifying assumption that the gene frequencies in migrant groups are deterministic. The present paper examines models which more closely mimic natural conditions, in which the gene frequencies in migrant groups are subject to stochastic effects. It is shown that some types of stochastic migration can cause dramatic changes in spatial correlations and variance. These changes depend on how the stochastic migration effects in the gene frequency recursion equations are shared among nearby subpopulations during the same generation. Only for cases where the effects are completely unshared are the equilibrium spatial and space-time correlations among adult subpopulations unaffected, but the variance is always inflated. The analyses here use novel methods, by recasting population genetic migration-drift models as space-time autoregressive moving average (STARMA) processes. Recent theorems for STARMA processes are employed for finding the spatial correlations, and for the first time in population genetics theory the complete set of space-time correlations, for systems with general patterns of migration rates and numbers of spatial dimensions. The space-time correlations provide a uniquely detailed description of a system, and thus form a link between observed spatial autocorrelation statistics and the underlying space-time population genetic process. STARMA theoretical processes have direct statistical analogues that can be applied for process identification, parameter estimation, model fitting, and forecasting in real systems.

Animals↗

Return and dynamics: the path of labor migration when workers differ in their skills and information is asymmetric.

"An implementation of the theory of labor migration under asymmetric information shows that return migration arises from the reinstatement of informational symmetry which induces low-skill workers, who are no longer pooled with high-skill workers, to return. When workers in an occupation constitute more than two skill levels, say four (without loss of generality), the following patterns emerge: Migration is sequential, that is, it proceeds in waves. Each wave breaks into workers who return and workers who stay; within waves the returning migrants are the low-skill workers. The average skill level of migrants is rising in the order of their wave."

Demography↗

Genetic variation and evolution of Polaskia chichipe (Cactaceae) under domestication in the Tehuacán Valley, central Mexico.

Polaskia chichipe is a columnar cactus under artificial selection in central Mexico because of its edible fruits. Our study explored the effect of human manipulation on levels and distribution of genetic variation in wild, silviculturally managed and cultivated sympatric populations. Total genetic variation, estimated in nine populations with five microsatellite loci, was H(T) = 0.658 +/- 0.026 SE, which was mainly distributed within populations (H(S) = 0.646) with low differentiation among them (F(ST) = 0.015). Fixation index (F(IS)) in all populations was positive, indicating a deficit of heterozygous individuals with respect to Hardy-Weinberg expectations. When populations were pooled by management type, the highest expected heterozygosity (H(E) = 0.631 +/- 0.031 SE) and the lowest fixation index (F(IS) = 0.07) were observed in wild populations, followed by cultivated populations (H(E) = 0.56 +/- 0.03 SE, F(IS) = 0.14), whereas the lowest variation was found in silviculturally managed populations (H(E) = 0.51 +/- 0.05 SE, F(IS) = 0.17). Low differentiation among populations under different management types (F(ST) 0.005, P < 0.04) was observed. A pattern of migration among neighbouring populations, suggested from isolation by distance (r2 = 0.314, P < 0.01), may have contributed to homogenizing populations and counteracting the effects of artificial selection. P. chichipe, used and managed for at least 700 generations, shows morphological differentiation, changes in breeding system and seed germination patterns associated with human management, with only slight genetic differences detected by neutral markers.

Biological Evolution↗

In vitro studies of the possible mechanisms whereby tumour promoters mediate their responses.

Carcinogenesis is commonly considered to be a multi-step process, comprising "initiation" and "promotion" events. Skin fibroblasts from patients with hereditary retinoblastoma (RB) and familial polyposis coli (FPC) were chosen for study since their predisposition to the tumour may be due to an inherited "initiation" event which is present in every somatic cell. Thus, one might predict that skin fibroblasts from these patients might exhibit an increased susceptibility to in vitro transformation, by either tumour promoters alone or by the complete carcinogen, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). In the case of skin fibroblasts from RB patients, transformation as measured by the ability of cells to grow in semi-solid medium and their migration in collagen gels, did not occur with either class of agent. However, experiments involving skin fibroblasts from FPC patients, showed these cells to grow in semi-solid medium following treatment with the tumour promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) alone, although their pattern of migration in collagen gels was unchanged and they were non-tumorigenic in nude mice. The clones which grew in semi-solid medium were also unaltered in terms of their migration in collagen gels and tumorigenicity in nude mice and were considered not to be completely transformed. These results are discussed in relation to theories that tumour promoters are only involved in cell selection and clonal expansion of initiated cells a second "mutational" event being required for complete transformation.

Carcinogens↗

Race and intra-urban migration.

Data from the urban renewal experience in Syracuse, New York are used to examine the impact of race on patterns of intra-urban migration. The results show that, overall, the migration patterns exhibited an exponential decay in frequency with increasing distance. Both blacks and whites display this pattern, but blacks tend to cluster more closely around the point of origin. Indirect evidence is developed to show that this phenomenon is due to blacks and whites having different access to information about housing, which ultimately maintains housing segregation.

Black or African American↗

Migrating endothelial cells are distinctly hyperglycosylated and express specific migration-associated cell surface glycoproteins.

Migration of endothelial cells is one of the first cellular responses in the cascade of events that leads to re-endothelialization of an injured vessel and neovascularization of growing tissues and tumors. To examine the hypothesis that endothelial cells express a specific migration-associated phenotype, we analyzed the cell surface glycoprotein expression of migrating bovine aortic endothelial cell (BAECs). Light microscopic analysis revealed an upregulation of binding sites for the lectins Concanavalin A (Con A), wheat germ agglutinin (WGA), and peanut agglutinin after neuraminidase treatment (N-PNA) on migrating endothelial cells relative to contact-inhibited cells. These findings were confirmed and quantitated with an enzyme-linked lectin assay (ELLA) of circularly scraped BAEC monolayers. The expression of migration-associated cell surface glycoproteins was also analyzed by SDS-PAGE. The overall expression of cell surface glycoproteins was upregulated on migrating BAECs. Migrating BAECs expressed Con A- and WGA-binding glycoproteins with apparent molecular masses of 25 and 48 kD that were not expressed by contact-inhibited BAEC monolayers and, accordingly, disappeared as circularly scraped monolayers reached confluence. Subconfluent BAEC monolayers expressed the same cell surface glycoconjugate pattern as migrating endothelial cells. FACS analysis of circularly scraped BAEC monolayers showed that the phenotypic changes of cell surface glycoprotein expression after release from growth arrest occurred before the recruitment of the cells into the cell cycle (3 vs. 12 h). Suramin, which inhibits endothelial cell migration, abrogated the expression of the migration-associated phenotype and induced the expression of a prominent 28-kD Con A- and WGA-binding cell surface glycoprotein. These results indicate that endothelial cells express a specific migration-associated phenotype, which is characterized by the upregulation of distinct cellular glycoconjugates and the expression of specific migration-associated cell surface glycoproteins.

Animals↗

Epithelial migration on the guinea-pig tympanic membrane: the influence of perforation and ventilating tube insertion.

The guinea-pig tympanic membrane was used to study epithelial migration by using an ink-dot staining technique. The normal tympanic membrane exhibited clear-cut migratory pathways, mainly in a superior direction. Tympanic membranes were acutely perforated and others had ventilating tubes inserted in them to determine their influence on the migratory process. The overall pattern of migration was found to be unaltered; only those cells were affected whose normal pathways had been disrupted by these procedures. The possible relationship of epithelial migration to ventilating tube extrusion is discussed.

Animals↗

Atypical migration of an impacted lower third molar.

This report describes the atypical migration of an impacted lower third molar tooth in a 42-year-old woman. Serial radiographs showed that, over a period of 13 years, the tooth migrated from its original disto-angular position posterior to and beneath the roots of the adjacent second molar to a more horizontal position beneath the roots of the first permanent molar. The tooth was surgically removed under general anaesthesia, with biopsy and curettage of soft tissue found in the bone posterior to the tooth along the path of migration. This pattern of tooth movement is highly unusual in an adult patient.

Adult↗

Specificity and plasticity of memory lymphocyte migration.

To exert immunological activity, T and B cells must leave the blood and enter different extravascular compartments in the body. An essential step in this process is their adhesion to microvascular endothelium and subsequent diapedesis into a target tissue. Naive and effector/memory T and B cells possess distinct repertoires of traffic molecules that restrict their ability to interact with specialized microvessels in different anatomic compartments and thus exhibit distinct patterns of migration. In addition, antigen-experienced lymphocytes are subdivided into different subsets based on their expression of characteristic sets of adhesion receptors that favor their accumulation in certain target organs, such as the skin and the gut. This article focuses on recent discoveries that have broadened our understanding of the "imprinting" mechanisms responsible for the generation of tissue-specific effector/memory lymphocytes, especially in the intestine. We discuss how gut-specific homing is acquired, maintained, and modulated and how these mechanisms might be harnessed to develop improved vaccine protocols and treatments for intestinal autoimmune diseases.

Animals↗

Migration of teeth in shortened dental arches.

In shortened dental arches (SDA) the remaining premolars tend to migrate distally. This may lead to a decrease of the vertical dimension, resulting in an increased load on the anterior teeth. Consequently the number and intensity of the occlusal contacts between the front teeth increase. This may result in interdental spacing in the upper front region. In this study the pattern of migration of the teeth in subjects with SDA (n = 60) is described. The SDA group is compared with subjects having complete dental arches (n = 72). Although a systemic effect of SDA has been found on interdental spacing for subjects under 40 years of age, it is concluded that this migration is within acceptable levels.

Adult↗

The story of the British special migration statistics.

"This paper describes a new data set from the 1991 Census called the Special Migration Statistics. Before release for general use by the U.K. social science and geographic community, it was essential to understand and to thoroughly check the data. This paper reports on the structure of the database and the checks carried out to verify its internal and external consistency. Finally, the paper summarises the pattern of migration revealed by the statistics for two illustrative spatial systems: wards in a large northern city and regions in Great Britain." The focus is on internal migration.

Censuses↗

Comparative migration, growth and development of Typhlocoelum cucumerinum sisowi in dabbling ducks and Typhlocoelum cucumerinum cucumerinum in diving ducks.

Experimental infections of mallards (Anas platyrhynchos L.) with Typhlocoelum cucumerinum sisowi (Skrjabin, 1913) and of canvasbacks (Aythya valisineria (Wilson)) with Typhlocoelum cucumerinum cucumerinum (Rudolphi, 1809) revealed significant differences in various parameters of the life-cycle in the definitive host. Both T. c. sisowi and T. c. cucumerinum migrate to the trachea via the abdominal cavity, air sacs and lungs, although T. c. cucumerinum migrate more quickly and more synchronously than T. c. sisowi. Typhlocoelum c. sisowi has a shorter expected life-span than T. c. cucumerinum but grows and reaches maturity more quickly than T. c. cucumerinum. Evidence suggests that T. c. cucumerinum has a higher fecundity than T. c. sisowi. These differences in the patterns of migration, growth and development are related not only to differences between the two host species but also to differences intrinsic to the parasites, and serve to provide biological support for considering them as separate sub-species.

Animals↗

Allele-specific patterns of the mouse parathyroid hormone-related protein: influences on cell adhesion and migration.

The mouse parathyroid hormone-like hormone Pthlh(Pro) and Pthlh(Thr) variants are linked with susceptibility and resistance to skin carcinogenesis of Car-S and Car-R mice, respectively, and with in vitro effects (Oncogene, 19: 5324-5328, 2000). We have identified an additional Pthlh variant, consisting of Thr and three amino-acid changes in the C-terminus (Pthlh(SerAspTyr)), carried by an evolutionarily distant Mus spretus (SPRET/Ei) inbred strain. When transfected into NCI-H520 tumor cells, this Pthlh(SerAspTyr) variant did not stimulate tumor growth in nude mice. Analysis of cell adhesion, migration, and invasion patterns of Pthlh(Pro)-, Pthlh(Thr)-, and Pthlh(SerAspTyr)-transfected NCI-H520 cells revealed a 1.5-fold decrease in adhesion efficiency on both collagen type I and Matrigel, and a 5-6-fold increase in migration capability in Pthlh(Pro) transfectants as compared to nontransfected, vector-transfected, Pthlh(Thr)-, or Pthlh(SerAspTyr)-transfected cells. These findings suggest that the cancer modifier effects of the mouse Pthlh gene are mediated by differential cell adhesion and migration effects of PTHrP variants.

Alleles↗

Analysis of EphA4 in the lesser spotted catshark identifies a primitive gnathostome expression pattern and reveals co-option during evolution of shark-specific morphology.

The Eph family is the largest known group of structurally related receptor tyrosine kinases (RTKs). Each Eph receptor has a specific Ephrin ligand, and these function to define spatial boundaries during development. Analyses of EphA4 in mouse, chick, frog and zebrafish embryos have implicated this gene in a number of developmental processes, including maintenance of segmental boundaries, axon guidance, limb development, neural crest migration and patterning of the ear. In order to determine which components of EphA4 function may be primitive for gnathostomes, we cloned EphA4 from the lesser spotted catshark ( Scyliorhinus canicula) and examined its expression pattern during shark embryonic development. Consistent with the patterns reported for bony fish and tetrapods, we observed segmental expression of EphA4 in the developing hindbrain and later in the pharyngeal arches of shark embryos. EphA4 was also detected during sensory organogenesis, in the developing ear, eye, nasal pits and lateral line. A dynamic pattern of EphA4expression occurs during shark fin development, suggesting an early role in outgrowth and patterning of the fin buds and a later role in tissue differentiation. We also observed several novel domains of EphA4expression that have not been reported in other vertebrates, including external gill buds, dermal denticles, median fins and claspers. While some of these domains may reflect co-option of EphA4expression to novel sites for development of shark-specific characters, others are more likely to be ancestral patterns of expression that were lost in other vertebrate lineages.

Amino Acid Sequence↗