Contrasting patterns of Y chromosome and mtDNA variation in Africa: evidence for sex-biased demographic processes

To investigate associations between genetic, linguistic, and geographic variation in Africa, we type 50 Y chromosome SNPs in 1122 individuals from 40 populations representing African geographic and linguistic diversity. We compare these patterns of variation with those that emerge from a similar analysis of published mtDNA HVS1 sequences from 1918 individuals from 39 African populations. For the Y chromosome, Mantel tests reveal a strong partial correlation between genetic and linguistic distances (r=0.33, P=0.001) and no correlation between genetic and geographic distances (r=-0.08, P>0.10). In contrast, mtDNA variation is weakly correlated with both language (r=0.16, P=0.046) and geography (r=0.17, P=0.035). AMOVA indicates that the amount of paternal among-group variation is much higher when populations are grouped by linguistics (Phi(CT)=0.21) than by geography (Phi(CT)=0.06). Levels of maternal genetic among-group variation are low for both linguistics and geography (Phi(CT)=0.03 and 0.04, respectively). When Bantu speakers are removed from these analyses, the correlation with linguistic variation disappears for the Y chromosome and strengthens for mtDNA. These data suggest that patterns of differentiation and gene flow in Africa have differed for men and women in the recent evolutionary past. We infer that sex-biased rates of admixture and/or language borrowing between expanding Bantu farmers and local hunter-gatherers played an important role in influencing patterns of genetic variation during the spread of African agriculture in the last 4000 years.     

Moderate chronic pain, weight and dietary intake in African-American adult patients with sickle cell disease

In this exploratory study, we evaluated weight status and dietary intake patterns during painful episodes in adult patients with SCD. Specifically, we explored the relation between pain severity and body mass index (BMI), and we tested the hypothesis that dietary intake would be reduced and dietary content altered during periods of increased pain. We conducted an analysis of survey data from 62 patients involved in a longitudinal evaluation of the relationship of medical and psychosocial factors to pain. Nearly half of patients with SCD were overweight, and 20% were obese. BMI was positively related to interference associated with pain. Although BMI was not statistically associated with reported pain severity, >40% of patients reported that they perceived their pain to be affected by their weight. Less than 20% of patients reported that they perceived that their weight affected their pain. Regarding dietary patterns, the majority of patients reported eating less during episodes of pain and significantly decreasing their intake of fats and proteins. We conclude that there is a need to better understand the relation among weight, dietary patterns and pain in patients with SCD in order to provide patients with accurate education and effective treatment recommendations for managing their disease and reducing current and future risks of lifestyle and disease-related morbidities.     

Doublecortin interacts with the ubiquitin protease DFFRX, which associates with microtubules in neuronal processes

Doublecortin (DCX) is a microtubule-associated protein involved in neuronal migration, which causes X-linked lissencephaly and subcortical laminar heterotopia (SCLH) when mutated. Here we show that DCX interacts with the ubiquitin-specific protease Drosophila fat facets related on X chromosome (DFFRX). This interaction was confirmed by targeted mutagenesis, colocalization, and immunoprecipitation studies. DFFRX is thought to deubiquitinate specific substrates including beta-catenin, preventing their degradation by the proteasome. Interestingly, unlike beta-catenin, no ubiquitinated forms of DCX could be detected, and indeed we show that DCX interacts with a novel recognition domain in DFFRX, located outside of its catalytic site. We also show that DFFRX associates with microtubules at specific subcellular compartments, including those enriched in DCX. These results thus suggest that in addition to vesicular trafficking, DCX may play a role in the regulation of cell adhesion via its interaction with DFFRX in migrating and differentiating neurons.     

Animal allergens

Animal allergen exposure in early childhood and its relationship to the development of atopic disease is a subject that has been evolving rapidly. Recently, several well-designed studies have helped elucidate previous, often conflicting findings on this topic. In addition, results from studies on farm-animal exposure have added strength to data on early dog and cat exposure. In this paper, we review several recent studies that have helped clarify the relationship between early animal-allergen exposure and childhood atopic disease.     

The EPICure study: associations and antecedents of neurological and developmental disability at 30 months of age following extremely preterm birth

AIMS: To describe perinatal factors associated with later morbidity among extremely preterm children at 30 months of age corrected for prematurity. POPULATION: Of 308 surviving children born at 相似文献