Genetic mapping of mutations in model systems has facilitated the identification of genes contributing to fundamental biological processes including human diseases. However, this approach has historically required the prior characterization of informative markers. Here we report a fast and cost-effective method for genetic mapping using next-generation sequencing that combines single nucleotide polymorphism discovery, mutation localization, and potential identification of causal sequence variants. In contrast to prior approaches, we have developed a hidden Markov model to narrowly define the mutation area by inferring recombination breakpoints of chromosomes in the mutant pool. In addition, we created an interactive online software resource to facilitate automated analysis of sequencing data and demonstrate its utility in the zebrafish and mouse models. Our novel methodology and online tools will make next-generation sequencing an easily applicable resource for mutation mapping in all model systems.[Supplemental material is available for this article.]There can be little argument that genetic mapping has made a substantial contribution to our understanding of biology. For many years these studies used phenotypically defined markers, such as those used by Morgan in Drosophila and Haldane in mice (Morgan 1911;Haldane et al. 1915). The modern era of genetic analysis was heralded by the recognition that variation in genomic DNA sequence itself could be used as a facile assay for mapping (Botstein et al. 1980). This was initially accomplished using analysis of restriction fragmentlength polymorphisms, which were later replaced by microsatellites and subsequently by single nucleotide polymorphisms (SNPs). Despite the remarkable technological advances, these approaches hold in common with those of Morgan and Haldane the utilization of prespecified markers. Next-generation sequencing (NGS) technology enables simultaneous discovery of very dense sets of informative markers and actual gene mapping in the same experiment. Here, we present a strategy and computational tools to map genes in model organisms using sequencing of pooled samples. The approach can be applied to any model organism with a characterized genome and also to both spontaneous and induced mutants. We demonstrate the utility of the strategy and efficiency of the computational approach by mapping spontaneous and ethylnitrosourea (ENU)-induced developmental mutants in zebrafish and mouse.Large-scale forward mutagenesis screens in zebrafish have been used with success to investigate fundamental developmental processes. While the recent completion of the zebrafish genome has greatly aided in the identification of genes, mapping analyses continue to rely on the use of traditional microsatellite markers. However, the utilization of SNPs for mapping of zebrafish mutants was proposed almost a decade ago (Stickney et al. 2002), large numbers of SNPs have been identified (Guryev et al. 2006;Bradley et al. 2007), and the application of NGS for SNP discovery and mutat...

Mammalian brain glycome remains a relatively poorly understood area compared to other large-scale “omics” studies, such as genomics and transcriptomics due to the inherent complexity and heterogeneity of glycan structure and properties. Here, we first performed spatial and temporal analysis of glycome expression patterns in the mammalian brain using a cutting-edge experimental tool based on liquid chromatography-mass spectrometry, with the ultimate aim to yield valuable implications on molecular events regarding brain functions and development. We observed an apparent diversity in the glycome expression patterns, which is spatially well-preserved among nine different brain regions in mouse. Next, we explored whether the glycome expression pattern changes temporally during postnatal brain development by examining the prefrontal cortex (PFC) at different time point across six postnatal stages in mouse. We found that glycan expression profiles were dynamically regulated during postnatal developments. A similar result was obtained in PFC samples from humans ranging in age from 39 d to 49 y. Novel glycans unique to the brain were also identified. Interestingly, changes primarily attributed to sialylated and fucosylated glycans were extensively observed during PFC development. Finally, based on the vast heterogeneity of glycans, we constructed a core glyco-synthesis map to delineate the glycosylation pathway responsible for the glycan diversity during the PFC development. Our findings reveal high levels of diversity in a glycosylation program underlying brain region specificity and age dependency, and may lead to new studies exploring the role of glycans in spatiotemporally diverse brain functions.

We propose the use of tongue range of motion ratio as an initial screening tool to assess for restrictions in tongue mobility. "Functional" ankyloglossia can thus be defined and treatment effects followed objectively by using the proposed grading scale: grade 1: tongue range of motion ratio is >80%, grade 2 50-80%, grade 3 < 50%, grade 4 < 25%.

A major question in the process of dendrite development and complexity is not whether neuronal activity plays a role, but how it contributes to specific components of the mature dendrite pattern. Neurons interpret activity into the influx of calcium ions leading to activation of signaling pathways. The dynamics of calcium-activated signaling pathways after neuronal activity and the contribution to formation of dendrite complexity remain unclear. Here, we show that one calcium activated signaling pathway, extracellular signal-regulated kinase (ERK), showed differential activity in cortical neurons. In response to depolarizing stimuli, ERK was active for less than an hour in most neurons, whereas in others ERK remained active for several hours. Further, neurons in which ERK activity was sustained, displayed greater dendrite complexity than neurons that did not display sustained ERK activity. Interestingly, this difference in dendrite complexity was detected in some, but not all, morphological parameters. Pharmacological inhibition of sustained ERK activity inhibited calcium-activated dendrite complexity. Increasing the duration and degree of ERK phosphorylation, and thus activity, with dominant negative MAP kinase phosphatase-1 accentuated dendrite complexity. Neurons in which ERK activity was sustained activated downstream nuclear targets including RSK, MSK, cAMP response element binding protein (CREB), CRE-mediated gene transcription, and stabilized c-Fos. Further, the increase in dendrite complexity mediated by sustained ERK activity was inhibited by expression of a dominant negative CREB. These data indicate that ERK-mediated activity induced dendrite complexity via sustained signaling and CREB-mediated signaling.

Restricted tongue mobility was associated with narrowing of the maxillary arch and elongation of the soft palate in this study. These findings suggest that variations in tongue mobility may affect maxillofacial development.