Mapping autism risk loci using genetic linkage and chromosomal rearrangements

Autism spectrum disorders (ASDs) are common, heritable neurodevelopmental conditions. The genetic architecture of ASDs is complex, requiring large samples to overcome heterogeneity. Here we broaden coverage and sample size relative to other studies of ASDs by using Affymetrix 10K SNP arrays and 1,181 [corrected] families with at least two affected individuals, performing the largest linkage scan to date while also analyzing copy number variation in these families. Linkage and copy number variation analyses implicate chromosome 11p12-p13 and neurexins, respectively, among other candidate loci. Neurexins team with previously implicated neuroligins for glutamatergic synaptogenesis, highlighting glutamate-related genes as promising candidates for contributing to ASDs.     

Genetic variation in Mon1a affects protein trafficking and modifies macrophage iron loading in mice

We undertook a quantitative trait locus (QTL) analysis in mice to identify modifier genes that might influence the severity of human iron disorders. We identified a strong QTL on mouse chromosome 9 that differentially affected macrophage iron burden in C57BL/10J and SWR/J mice. A C57BL/10J missense allele of an evolutionarily conserved gene, Mon1a, cosegregated with the QTL in congenic mouse lines. We present evidence that Mon1a is involved in trafficking of ferroportin, the major mammalian iron exporter, to the surface of iron-recycling macrophages. Differences in amounts of surface ferroportin correlate with differences in cellular iron content. Mon1a is also important for trafficking of cell-surface and secreted molecules unrelated to iron metabolism, suggesting that it has a fundamental role in the mammalian secretory apparatus.     

Sequence variants in the autophagy gene IRGM and multiple other replicating loci contribute to Crohn's disease susceptibility

A genome-wide association scan in individuals with Crohn's disease by the Wellcome Trust Case Control Consortium detected strong association at four novel loci. We tested 37 SNPs from these and other loci for association in an independent case-control sample. We obtained replication for the autophagy-inducing IRGM gene on chromosome 5q33.1 (replication P = 6.6 x 10(-4), combined P = 2.1 x 10(-10)) and for nine other loci, including NKX2-3, PTPN2 and gene deserts on chromosomes 1q and 5p13.     

Genome-wide meta-analysis increases to 71 the number of confirmed Crohn's disease susceptibility loci

We undertook a meta-analysis of six Crohn's disease genome-wide association studies (GWAS) comprising 6,333 affected individuals (cases) and 15,056 controls and followed up the top association signals in 15,694 cases, 14,026 controls and 414 parent-offspring trios. We identified 30 new susceptibility loci meeting genome-wide significance (P < 5 × 10??). A series of in silico analyses highlighted particular genes within these loci and, together with manual curation, implicated functionally interesting candidate genes including SMAD3, ERAP2, IL10, IL2RA, TYK2, FUT2, DNMT3A, DENND1B, BACH2 and TAGAP. Combined with previously confirmed loci, these results identify 71 distinct loci with genome-wide significant evidence for association with Crohn's disease.     

WDR62 is associated with the spindle pole and is mutated in human microcephaly

Autosomal recessive primary microcephaly (MCPH) is a disorder of neurodevelopment resulting in a small brain. We identified WDR62 as the second most common cause of MCPH after finding homozygous missense and frame-shifting mutations in seven MCPH families. In human cell lines, we found that WDR62 is a spindle pole protein, as are ASPM and STIL, the MCPH7 and MCHP7 proteins. Mutant WDR62 proteins failed to localize to the mitotic spindle pole. In human and mouse embryonic brain, we found that WDR62 expression was restricted to neural precursors undergoing mitosis. These data lend support to the hypothesis that the exquisite control of the cleavage furrow orientation in mammalian neural precursor cell mitosis, controlled in great part by the centrosomes and spindle poles, is critical both in causing MCPH when perturbed and, when modulated, generating the evolutionarily enlarged human brain.     

浅谈高职网络课程的教学有效性

网络课程建设在突飞猛进,取得一些成就的同时,仍然存在着与教育学习不相适应的方面。通过分析网络课程的特点、存在的问题,提出了网络课程建设中的一些建议,以提高网络课程的教学有效性。     

Immunological and morphological consequences of vasectomy in the rabbit.

Cell-mediated immunity to spermatozoa was detected in vitro 6--18 months after vasectomy in the rabbit. The autoimmunity was accompanied by aspermatogenic orchitis in the testes and epididymides.     

Purification of canine myocardial mitochondrial creatine kinase

Summary Mitochondrial creatine kinase, purified for the first time, is a dimeric molecule with a mol.wt of 82,000 and does not hybridize with M or B subunits or react to their specific antiserum. A specific antiserum to the mitochondrial form was developed which does not cross-react with the B or M subunits. Thus, the mitochondrial form is biochemically and immunologically unique.Supported in part by the Special Center of Research in Ischemic Heart Disease (1 P17 HL 17646).I thank Ann Grace for her technical assistance and Ava Ysaguirre for typing the mansucript.     

No evidence for preservation of somatostatin-containing neurons after intrastriatal injections of quinolinic acid

Intrastriatal injections of excitotoxic amino acids and their analogues (for example kainate and ibotenate) elicit a pattern of neuronal degeneration that is similar in many respects to that observed in Huntington's disease. In this disease there is a progressive degeneration of most types of intrinsic neuron but somatostatin and neuropeptide Y levels are increased 3-5-fold. This may be attributed to the selective preservation of a sub-class of striatal aspiny neurons, in which these two peptides are co-localized together with the enzyme NADPH-diaphorase. Beal et al. reported recently that following intrastriatal injections of quinolinic acid in rats, medium-sized aspiny neurons were selectively preserved and they suggested that quinolinic acid which is found in human brain might cause the neuronal degeneration seen in Huntington's disease. We have used immunocytochemical and enzyme histochemical techniques to examine this selective toxicity but find no evidence to support this finding. We conclude that there are substantial differences between the immunocytochemical changes detected in postmortem Huntington's disease brain and those following quinolinic-acid-induced degeneration.