A genetic and epigenetic analysis of the noradrenaline transporter

In this study the importance of epigenetic control of the NET gene was demonstrated using mouse and human tissues. Differences in the state of the NET gene were identified between healthy individuals and patients with postural orthostatic tachycardia syndrome (POTS), potentially leading to new treatment possibilities.

Morphological and biochemical alterations of abalone testicular germ cells and spawned sperm and their fertilizing ability

In this study, we aimed to detect morphological and biochemical changes in developing germ cells (Gc), testicular sperm (Tsp), and spawned sperm (Ssp) using capacitation-associated characteristics. Gradual changes in the profiles of two membrane proteins, namely NaCl- and detergent-extractable proteins, were observed as compared Gc with Tsp and Tsp with Ssp. These membrane modifications were accomplished mostly through the introduction of new protein sets, both peripheral and integral, into Tsp and Ssp membranes. Activation of serine proteases, particularly in Ssp detergent-extracted proteins with the molecular masses of 38–130 kDa was evident and marked a major difference between Ssp and Tsp. An increase in the level of tyrosine phosphorylation of the proteins ranging from 15 to 20 kDa was noted in Tsp and remained constant in Ssp. Specifically, these three capacitation-associated characteristics could be detected in Ssp, possessing full fertilizing capacity. The lack of an activated proteolytic activity in Tsp resulted in a delayed fertilization, but not affected fertilizing ability. We believe that these characteristics should be advantageous in predicting abalone sperm fertilizing capability, particularly in cases when isolated germ cells or purified Tsp are used in place of spawned sperm in abalone aquaculture.

Analytical relationship between family history and genetic and environmental risks, with application to female breast cancer

It is well established in genetic epidemiology that family history is an important indicator of familial aggregation of disease in a family. A strong genetic risk factor or an environmental risk factor with high familial correlation can result in a strong family history. In this paper, family history refers to the number of first-degree relatives affected with the disease. Cui and Hopper (Journal of Epidemiology and Biostatistics 2001; 6: 331-342) proposed an analytical relationship between family history and relevant genetic parameters. In this paper we expand the relationship to both genetic and environmental risk factors. We established a closed-form formula for family history as a function of genetic and environmental parameters which include genetic and environmental relative risks, genotype frequency, prevalence and familial correlation of the environmental risk factor. The relationship is illustrated by an example of female breast cancer in Australia. For genetic and environmental relative risks less than 10, most of the female breast cancer cases occur between the age of 40 and 60 years. A higher genetic or environmental relative risk will move the peak of the distribution to a younger age. A more common disease allele or more prevalent environmental risk factor will move the peak to an older age. For a proband with breast cancer, it is most likely (with probability ge80%) that none of her first-degree relatives is affected with the disease. To enable the probability of having a positive family history to reach 50%, the environmental relative risks must be extremely as high as 100, the familial correlation as high as 0.8 and the prevalence as low as 0.1. For genetic risk alone, even the relative risk is as high as 100, the probability of having a positive family history can only reach about 30%. This suggests that the environmental risk factor seems to play a more important role in determining a strong family history than the genetic risk factor.

Genetic and environmental influences on variation in balance performance among female twin pairs aged 21-82 years

Genetic and environmental influences on variation in balance performance were measured in 93 monozygous and 83 dizygous female twin pairs aged 21–82 years (mean age, 50.5 years) in Melbourne, Australia, between 1999 and 2003. The authors administered clinical (Lord's Balance Test and Step Test) and laboratory tests of static and dynamic balance from the Chattecx Balance System with and without distractor tasks. The authors conducted factor analysis and estimated genetic and environmental variance components and heritability (defined as additive genetic variance as a proportion of all variance, after adjustment for age) using a multivariate normal model with the statistical package FISHER. Three factors were identified and adjusted for age. Heritability was 46% (standard error (SE), 9) for the "sensory balance tests" factor and 30% (SE, 9) for the "static and dynamic perturbations" factor. For both factors, the remaining variance was attributed to unique environmental effects. There was no evidence that genetic factors influenced variation in the "dynamic weight shift tests" factor, with environmental effects shared by twins accounting for 38% (SE, 7) of variance. Neither genetic nor environmental proportions of variance differed significantly between twin subgroups by age (≤50/>50 years). An age-related decline in performance measures was found across the whole sample. These results imply that balance impairments may have a heritable element.

Conflict between genetic and phenotypic differentiation : the evolutionary history of a ‘lost and rediscovered’ shorebird

Understanding and resolving conflicts between phenotypic and genetic differentiation is central to evolutionary research. While phenotypically monomorphic species may exhibit deep genetic divergences, some morphologically distinct taxa lack notable genetic differentiation. Here we conduct a molecular investigation of an enigmatic shorebird with a convoluted taxonomic history, the White-faced Plover (Charadrius alexandrinus dealbatus), widely regarded as a subspecies of the Kentish Plover (C. alexandrinus). Described as distinct in 1863, its name was consistently misapplied in subsequent decades until taxonomic clarification ensued in 2008. Using a recently proposed test of species delimitation, we reconfirm the phenotypic distinctness of dealbatus. We then compare three mitochondrial and seven nuclear DNA markers among 278 samples of dealbatus and alexandrinus from across their breeding range and four other closely related plovers. We fail to find any population genetic differentiation between dealbatus and alexandrinus, whereas the other species are deeply diverged at the study loci. Kentish Plovers join a small but growing list of species for which low levels of genetic differentiation are accompanied by the presence of strong phenotypic divergence, suggesting that diagnostic phenotypic characters may be encoded by few genes that are difficult to detect. Alternatively, gene expression differences may be crucial in producing different phenotypes whereas neutral differentiation may be lagging behind.

Genes and song : genetic and social connections in fragmented habitat in a woodland bird with limited dispersal

Understanding the processes leading to population declines in fragmented landscapes is essential for successful conservation management. However, isolating the influence of disparate processes, and dispersal in particular, is challenging. The Grey Shrike-thrush, Colluricincla harmonica, is a sedentary woodland-dependent songbird, with learned vocalizations whose incidence in suitable habitat patches falls disproportionally with decline in tree cover in the landscape. Although it has been suggested that gaps in tree cover might act as barriers to its dispersal, the species remains in many remnants of native vegetation in agricultural landscapes, suggesting that it may have responded to habitat removal and fragmentation by maintaining or even increasing dispersal distances. We quantified population connectivity of the Grey Shrike-thrush in a system fragmented over more than 120 years using genetic (microsatellites) and acoustic (song types) data. First, we tested for population genetic and acoustic structure at regional and local scales in search of barriers to dispersal or gene flow and signals of local spatial structuring indicative of restricted dispersal or localized acoustic similarity. Then we tested for effects of habitat loss and fragmentation on genetic and acoustic connectivity by fitting alternative models of mobility (isolation-by-distance [the null model] and reduced and increased movement models) across treeless vs. treed areas. Birds within 5 km of each other had more similar genotypes and song types than those farther away, suggesting that dispersal and song matching are limited in the region. Despite restricted dispersal detected for females (but not males), populations appeared to be connected by gene flow and displayed some cultural (acoustic) connectivity across the region. Fragmentation did not appear to impact greatly the dispersal of the Grey Shrike-thrush: none of the mobility models fit the genetic distances of males, whereas for females, an isolation-by-distance model could not be rejected in favor of the models of reduced or increased movement through treeless gaps. However, dissimilarities of the song types were more consistent with the model of reduced cultural connectivity through treeless areas, suggesting that fragmentation impedes song type sharing in the Grey Shrike-thrush. Our paper demonstrates that habitat fragmentation hinders important population processes in an Australian woodland bird even though its dispersal is not detectably impacted.

Evidence from genetic and Lagrangian drifter data for transatlantic transport of small juvenile green turtles

Aim  A key life-history component for many animals is the need for movement between different geographical locations at particular times. Green turtle (Chelonia mydas) hatchlings disperse from their natal location to spend an early pelagic stage in the ocean, followed by a neritic stage where small juveniles settle in coastal areas. In this study, we combined genetic and Lagrangian drifter data to investigate the connectivity between natal and foraging locations. In particular we focus on the evidence for transatlantic transport. Location  Atlantic Ocean.

Methods  We used mitochondrial DNA (mtDNA) sequences (n = 1567) from foraging groups (n = 8) and nesting populations (n = 12) on both sides of the Atlantic. Genetic data were obtained for Cape Verde juvenile turtles, a foraging group not previously sampled for genetic study. Various statistical methods were used to explore spatial genetics and population genetic structure (e.g. exact tests of differentiation, Geneland and analysis of molecular variance). Many-to-many mixed stock analysis estimated the connectivity between nesting and foraging groups.

Results  Our key new finding is robust evidence for connectivity between a nesting population on the South American coast (25% of the Surinam nesting population are estimated to go to Cape Verde) and a foraging group off the coast of West Africa (38% of Cape Verde juveniles are estimated to originate from Surinam), thus extending the results of previous investigations by confirming that there is substantial transatlantic dispersal in both directions. Lagrangian drifter data demonstrated that transport by drift across the Atlantic within a few years is possible.

Main conclusions  Small juvenile green turtles seem capable of dispersing extensively, and can drop out of the pelagic phase on a transatlantic scale (the average distance between natal and foraging locations was 3048 km). Nevertheless, we also find support for the ‘closest-to-home’ hypothesis in that the degree of contribution from a nesting population to a foraging group is correlated with proximity. Larger-sized turtles appear to feed closer to their natal breeding grounds (the average distance was 1133 km), indicating that those that have been initially transported to far-flung foraging grounds may still be able to move nearer to home as they grow larger.

Myopia : why study the mechanisms of myopia? Novel approaches to risk factors Signaling eye growth- how could basic biology be translated into clinical insights? Where are genetic and proteomic approaches leading? How does visual function contribute to an

On July 26–29, 2010 the 13th International Myopia Conference was held in Tübingen, Germany and included 17 separate symposia, each with 3–5 presentations. Here, in a single paper, the chairs of those Symposia describe the scientific advances noted at the conference and include the full abstracts of the individual myopia papers presented in each symposium along with the authors and their institutions. The 17 Symposia covered 7 topics: Why Study the Mechanisms of Myopia?; Novel Approaches to Risk Factors; Signaling Eye Growth- How Could Basic Biology Be Translated into Clinical Insights?; Where Are Genetic and Proteomic Approaches Leading?; How Does Visual Function Contribute to and Interact with Ametropia?; Does Eye Shape Matter?; Why Ametropia at All?

Population-level perspectives on global change : genetic and demographic analyses indicate various scales, timing, and causes of scyphozoan jellyfish blooms

Whether a perceived increase in the abundance of jellyfishes is related to changing marine environments has been considered primarily using large-scale analyses of multi-species assemblages. Yet jellyfish blooms-rapid increases in the biomass of pelagic coelenterate species-are single-species demographic events. Using published and new genetic analyses and population surveys, we investigate whether there may be a critical knowledge gap between the scales of recent analyses and the scales of natural phenomena. We find that scyphomedusae may show population genetic structure over scales of tens to hundreds of kilometers, that environments vary regionally and locally, and that populations of medusae can display uncorrelated dynamics on these scales. These findings suggest genetic differences between populations and/or environmental differences between sites are important determinants of population dynamics in these jellyfishes. Moreover, the local abundance of medusae may be most strongly correlated with preceding rather than current local environmental conditions, indicating there is a cumulative time-course to the formation of 'blooms'. Broad-scale macro-ecological analyses will need to build from coordinated, long-term, fine-grained studies to synthesize, rather than mask, population-level phenomena in larger-scale analyses. © 2014 Springer International Publishing Switzerland.

Age-related proteostasis and metabolic alterations in Caspase-2-deficient mice.

Ageing is a complex biological process for which underlying biochemical changes are still largely unknown. We performed comparative profiling of the cellular proteome and metabolome to understand the molecular basis of ageing in Caspase-2-deficient (Casp2(-/-)) mice that are a model of premature ageing in the absence of overt disease. Age-related changes were determined in the liver and serum of young (6-9 week) and aged (18-24 month) wild-type and Casp2(-/-) mice. We identified perturbed metabolic pathways, decreased levels of ribosomal and respiratory complex proteins and altered mitochondrial function that contribute to premature ageing in the Casp2(-/-) mice. We show that the metabolic profile changes in the young Casp2(-/-) mice resemble those found in aged wild-type mice. Intriguingly, aged Casp2(-/-) mice were found to have reduced blood glucose and improved glucose tolerance. These results demonstrate an important role for caspase-2 in regulating proteome and metabolome remodelling during ageing.