Mitochondrial phylogeography of the killifish Aphanius fasciatus (Teleostei, Cyprinodontidae) reveals highly divergent Mediterranean populations

We studied the genetic structure of the Mediterranean killifish Aphanius fasciatus. Analysis of the sequence variation in a 372-bp portion of the mitochondrial control region in 623 fish from 27 sampling sites along the species’ distributional range (Tyrrhenian coast, Sardinia, Sicily, Adriatic coast, Malta, Tunisia, and Greece) yielded 120 distinct haplotypes. Most of the haplotypes are unique, and only 15 % are shared among different populations. The high F _ST value (=0.80) suggests a strong population genetic structuring. The phylogenetic analysis based on Bayesian inference, maximum likelihood and maximum parsimony, and the median-joining network show a sharp separation of the Southeastern Sicilian populations (belonging to the Hyblean region) and of the fluvial Tunisian population of Rio Melah from the others. The Adriatic, the Eastern Sicilian, and the Greek populations are well differentiated, while the group of populations from the Central-Western Mediterranean does not show a clear pattern of differentiation. Our findings indicate that the current genetic structuring of A. fasciatus reflects historical geographical patterns occurring within the Mediterranean basin from the Late Miocene to the Pleistocene. The presence of divergent evolutionary entities in the Hyblean region and the Tunisian Rio Melah supports their inclusion as target areas for the conservation of A. fasciatus.     

Brain cortical assessment by MRI in fetuses with left congenital diaphragmatic hernia

Objective

To evaluate fetal brain development using MRI (magnetic resonance imaging) in CDH (congenital diaphragmatic hernia).

Methods

52 isolated left CDH and 104 control fetuses were imaged using MRI. Brain morphometry (Biparietal diameter—BPD, brain fronto-occipital diameter—BFOD, third ventricle, posterior ventricles, transcerebellar diameter—TCD, anteroposterior and craniocaudal cerebellar vermis diameter—AP and CC) and cortical structures (bilateral cingulate fissure—CF, insular fissure—IF, insular depth - ID) were compared with controls using Mann–Whitney test.

Results

Median gestational age at MRI (p = 0.95)and the median biparietal diameter (p = 0.737) were comparable. Among morphometric parameters, only the brain fronto-occipital diameter was significantly smaller in CDH (p = 0.001) and the third ventricle was significantly greater in CDH (<0.0001). Among cortical structures, the cingulate and insular fissures were significantly deeper in CDH fetuses (p < 0.0001) as the insular depth ID was smaller in CDH (p < 0.03).

Conclusions

CDH fetuses have a smaller fronto-occipital diameter, reduced insular depth, deeper cingulate and insular fissure, and greater third ventricle width as compared to controls. These findings suggest that left CDH may have an impact on fetal brain development with an overall reduction in brain volume.     

Maternally inherited autosomal dominant PLAG-1 related Silver Russell syndrome in a fetus with intra-uterine growth restriction

We report a case of maternally inherited autosomal dominant PLAG-1 related Silver Russell syndrome (SRS) in a fetus with IUGR and a mother who had growth and feeding problems in early life, dextrocardia and an atrio-ventricular septal defect. Amniocentesis was performed due to marked intra-uterine growth restriction (IUGR). The array was normal. Whole exome sequencing (WES) revealed a maternally inherited heterozygous likely pathogenic variant in PLAG1 (NM_002655.3): c.402delT p.(Gly135Aspfs*94). This variant has not been reported previously. PLAG1 pathogenic variants are associated with autosomal dominant Silver Russell syndrome, which fits with the clinical phenotypes of both fetus and mother. PLAG1 variants have previously been reported post-natally in Silver Russell syndrome, but the phenotype tends to be milder than in 11p15.5 methylation-related cases with fewer physical features. Although cardiac anomalies are uncommon in SRS, they have been previously reported. To our knowledge, dextrocardia has not been previously associated with SRS and there were no other potential causative genetic variants found. This report aims to highlight this rare type of SRS as a cause of IUGR.     

Lateral flow assay applied to pesticides detection: recent trends and progress

Environmental Science and Pollution Research - Devices based on lateral flow assay (LFA) have been gaining more and more space in the detection market mainly due to their simplicity, speed, and low...     

Selection of both habitat and genes in specialized and endangered caribou

Genetic mechanisms determining habitat selection and specialization of individuals within species have been hypothesized, but not tested at the appropriate individual level in nature. In this work, we analyzed habitat selection for 139 GPS-collared caribou belonging to 3 declining ecotypes sampled throughout Northwestern Canada. We used Resource Selection Functions comparing resources at used and available locations. We found that the 3 caribou ecotypes differed in their use of habitat suggesting specialization. On expected grounds, we also found differences in habitat selection between summer and winter, but also, originally, among the individuals within an ecotype. We next obtained Single Nucleotide Polymorphisms (SNPs) for the same caribou individuals, we detected those associated to habitat selection, and then identified genes linked to these SNPs. These genes had functions related in other organisms to habitat and dietary specializations, and climatic adaptations. We therefore suggest that individual variation in habitat selection was based on genotypic variation in the SNPs of individual caribou, indicating that genetic forces underlie habitat and diet selection in the species. We also suggest that the associations between habitat and genes that we detected may lead to lack of resilience in the species, thus contributing to caribou endangerment. Our work emphasizes that similar mechanisms may exist for other specialized, endangered species.     

Spiking organic chemicals onto sediments for ecotoxicological analyses: an overview of methods and procedures

Environmental Science and Pollution Research - Laboratory testing with spiked sediments with organic contaminants is a valuable tool for ecotoxicologists to study specific processes such as effects...