MYH9 is associated with nondiabetic end-stage renal disease in African Americans

As end-stage renal disease (ESRD) has a four times higher incidence in African Americans compared to European Americans, we hypothesized that susceptibility alleles for ESRD have a higher frequency in the West African than the European gene pool. We carried out a genome-wide admixture scan in 1,372 ESRD cases and 806 controls and found a highly significant association between excess African ancestry and nondiabetic ESRD (lod score = 5.70) but not diabetic ESRD (lod = 0.47) on chromosome 22q12. Each copy of the European ancestral allele conferred a relative risk of 0.50 (95% CI = 0.39-0.63) compared to African ancestry. Multiple common SNPs (allele frequencies ranging from 0.2 to 0.6) in the gene encoding nonmuscle myosin heavy chain type II isoform A (MYH9) were associated with two to four times greater risk of nondiabetic ESRD and accounted for a large proportion of the excess risk of ESRD observed in African compared to European Americans.     

Common variants near MC4R are associated with fat mass, weight and risk of obesity

To identify common variants influencing body mass index (BMI), we analyzed genome-wide association data from 16,876 individuals of European descent. After previously reported variants in FTO, the strongest association signal (rs17782313, P = 2.9 x 10(-6)) mapped 188 kb downstream of MC4R (melanocortin-4 receptor), mutations of which are the leading cause of monogenic severe childhood-onset obesity. We confirmed the BMI association in 60,352 adults (per-allele effect = 0.05 Z-score units; P = 2.8 x 10(-15)) and 5,988 children aged 7-11 (0.13 Z-score units; P = 1.5 x 10(-8)). In case-control analyses (n = 10,583), the odds for severe childhood obesity reached 1.30 (P = 8.0 x 10(-11)). Furthermore, we observed overtransmission of the risk allele to obese offspring in 660 families (P (pedigree disequilibrium test average; PDT-avg) = 2.4 x 10(-4)). The SNP location and patterns of phenotypic associations are consistent with effects mediated through altered MC4R function. Our findings establish that common variants near MC4R influence fat mass, weight and obesity risk at the population level and reinforce the need for large-scale data integration to identify variants influencing continuous biomedical traits.     

The insecticidal potential of venom peptides

Pest insect species are a burden to humans as they destroy crops and serve as vectors for a wide range of diseases including malaria and dengue. Chemical insecticides are currently the dominant approach for combating these pests. However, the de-registration of key classes of chemical insecticides due to their perceived ecological and human health risks in combination with the development of insecticide resistance in many pest insect populations has created an urgent need for improved methods of insect pest control. The venoms of arthropod predators such as spiders and scorpions are a promising source of novel insecticidal peptides that often have different modes of action to extant chemical insecticides. These peptides have been optimized via a prey–predator arms race spanning hundreds of millions of years to target specific types of insect ion channels and receptors. Here we review the current literature on insecticidal venom peptides, with a particular focus on their structural and pharmacological diversity, and discuss their potential for deployment as insecticides.     

Common variants at 12q14 and 12q24 are associated with hippocampal volume

Aging is associated with reductions in hippocampal volume that are accelerated by Alzheimer's disease and vascular risk factors. Our genome-wide association study (GWAS) of dementia-free persons (n = 9,232) identified 46 SNPs at four loci with P values of <4.0 × 10(-7). In two additional samples (n = 2,318), associations were replicated at 12q14 within MSRB3-WIF1 (discovery and replication; rs17178006; P = 5.3 × 10(-11)) and at 12q24 near HRK-FBXW8 (rs7294919; P = 2.9 × 10(-11)). Remaining associations included one SNP at 2q24 within DPP4 (rs6741949; P = 2.9 × 10(-7)) and nine SNPs at 9p33 within ASTN2 (rs7852872; P = 1.0 × 10(-7)); along with the chromosome 12 associations, these loci were also associated with hippocampal volume (P < 0.05) in a third younger, more heterogeneous sample (n = 7,794). The SNP in ASTN2 also showed suggestive association with decline in cognition in a largely independent sample (n = 1,563). These associations implicate genes related to apoptosis (HRK), development (WIF1), oxidative stress (MSR3B), ubiquitination (FBXW8) and neuronal migration (ASTN2), as well as enzymes targeted by new diabetes medications (DPP4), indicating new genetic influences on hippocampal size and possibly the risk of cognitive decline and dementia.     

Mouse ooplasm confers context-specific reprogramming capacity

Enucleated oocytes have the distinctive ability to reprogram somatic nuclei back to totipotency. Here, we investigate genome-scale DNA methylation patterns after nuclear transfer and compare them to the dynamics at fertilization. We identify specific targets for DNA demethylation after nuclear transfer, such as germline-associated promoters, as well as unique limitations that include certain repetitive element classes.     

A new sceloporine lizard from Oaxaca, Mexico

Sceloporus megalepidurus halli, subsp. nov., is described from San Jos&eacute; Lachiguiri, Oaxaca, Mexico, from one adult male.     

Pocket gophers ( Thomomys talpoides ) in successional stages of spruce-fir forest in Idaho

This study examined (1) the relative abundance of the pocket gopher ( Thomomys talpoides ) in four successive stages (1&ndash;10, 11&ndash;39, 40&ndash;79, and 80+ years following disturbance) of spruce-fir forest; (2) the relationship between number of gopher sign (mounds and earth plugs) with gopher density; and (3) a method of sampling pocket gopher populations using a 500 by 4 m strip transect. The number of gopher mounds was significantly correlated with the number of earth plugs. Data were pooled and a categorical log linear analysis used to test for significant differences in pocket gopher sign between the four successive stages. The 1&ndash;10 and the 80+ -year-old sites had significantly more gopher sign than the 11&ndash;39 and the 40&ndash;79 year-old sites. No significant differences were found between the 11&ndash;39 and the 40&ndash;79-year-old sites, or between the 1&ndash;10 and the 80+ -year-old sites. The difference in population densities may be due to understory vegetation differences between the successional stages. There was a significant correlation between amount of gopher sign and gophers caught in each of the study sites. This indicates that counts of pocket gopher sign may be used to estimate pocket gopher density. The strip transect is recommended as the most appropriate method when sampling heterogeneous habitats or when there is cause to suspect gopher populations may be aggregated within the area rather than spaced randomly or regularly.     

Mutations in genes encoding melanosomal proteins cause pigmentary glaucoma in DBA/2J mice.

Pigmentary glaucoma is a significant cause of human blindness. Abnormally liberated iris pigment and cell debris enter the ocular drainage structures, leading to increased intraocular pressure (IOP) and glaucoma. DBA/2J (D2) mice develop a form of pigmentary glaucoma involving iris pigment dispersion (IPD) and iris stromal atrophy (ISA). Using high-resolution mapping techniques, sequencing and functional genetic tests, we show that IPD and ISA result from mutations in related genes encoding melanosomal proteins. IPD is caused by a premature stop codon mutation in the Gpnmb (GpnmbR150X) gene, as proved by the occurrence of IPD only in D2 mice that are homozygous with respect to GpnmbR150X; otherwise, similar D2 mice that are not homozygous for GpnmbR150X do not develop IPD. ISA is caused by the recessive Tyrp1b mutant allele and rescued by the transgenic introduction of wildtype Tyrp1. We hypothesize that IPD and ISA alter melanosomes, allowing toxic intermediates of pigment production to leak from melanosomes, causing iris disease and subsequent pigmentary glaucoma. This is supported by the rescue of IPD and ISA in D2 eyes with substantially decreased pigment production. These data indicate that pigment production and mutant melanosomal protein genes may contribute to human pigmentary glaucoma. The fact that hypopigmentation profoundly alleviates the D2 disease indicates that therapeutic strategies designed to decrease pigment production may be beneficial in human pigmentary glaucoma.     

Effects of the adenylate cyclase activator forskolin and its inactive derivative 1,9-dideoxyforskolin on insect cytochrome P-450 dependent steroid hydroxylase activity

The adenylate cyclase activator forskolin and its pharmacologically inactive derivative 1,9-dideoxyforskolin were found to inhibit in a dose-dependent fashion the ecdysone 20-monooxygenase activity associated with wandering stage larvae ofDrosophila melanogaster and fat body and midgut from last instar larvae of the tobacco hornworm,Manduca sexta. The concentrations of these labdane diterpenes required to elicit a 50% inhibition of the cytochrome P-450 dependent steroid hydroxylase activity in the insect tissues ranged from approximately 5×10^–6 to 5×10^–4 M.     

Mutations in ATP2A2, encoding a Ca2+ pump, cause Darier disease

Darier disease (DD) is an autosomal-dominant skin disorder characterized by loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. Recently we constructed a 2.4-Mb, P1-derived artificial chromosome contig spanning the DD candidate region on chromosome 12q23-24.1. After screening several genes that mapped to this region, we identified mutations in the ATP2A2 gene, which encodes the sarco/endoplasmic reticulum Ca2(+)-ATPase type 2 isoform (SERCA2) and is highly expressed in keratinocytes. Thirteen mutations were identified, including frameshift deletions, in-frame deletions or insertions, splice-site mutations and non-conservative missense mutations in functional domains. Our results demonstrate that mutations in ATP2A2 cause DD and disclose a role for this pump in a Ca(2+)-signalling pathway regulating cell-to-cell adhesion and differentiation of the epidermis.