In the developing brain, heightened plasticity during the critical period enables the proper formation of neural circuits. Here we identify the “navigator” neurons, a group of perinatally born olfactory sensory neurons, as playing an essential role in establishing the olfactory map during the critical period. The navigator axons project circuitously in the olfactory bulb and traverse multiple glomeruli before terminating in perspective glomeruli. These neurons undergo a phase of exuberant axon growth and exhibit a shortened lifespan. Single cell transcriptome analyses reveal distinct molecular signatures for the navigators. Extending their lifespan prolongs the period of exuberant growth and perturbs axon convergence. Conversely, genetic ablation experiment indicates that, despite postnatal neurogenesis, only the navigators are endowed with the ability to establish a convergent map. The presence and the proper removal of the navigator neurons are both required to establish tight axon convergence into the glomeruli.
No associated publication
Sex, Specimen part, Cell line
View SamplesThe hair of all mammals consists of terminally differentiated cells that undergo a specialized form of apoptosis called cornification. While DNA is destroyed during cornification, the extent to which RNA is lost is unknown. Here we find that multiple types of RNA are incompletely degraded after hair shaft formation in both mouse and human. Notably, mRNAs and short regulatory microRNAs (miRNAs) are stable in the hair as far as 10 cm from the scalp. To better characterize the post-apoptotic RNAs that escape degradation in the hair, we performed sequencing (RNA-seq) on RNA isolated from hair shafts pooled from several individuals. This hair shaft RNA library, which encompasses different hair types, genders, and populations, revealed 7,193 mRNAs, 449 miRNAs and thousands of unannotated transcripts that remain in the post-apoptotic hair. A comparison of the hair shaft RNA library to that of viable keratinocytes revealed surprisingly similar patterns of gene coverage and indicates that degradation of RNA is highly inefficient during apoptosis of hair lineages. The generation of a hair shaft RNA library could be used as months of accumulated transcriptional history useful for retrospective detection of disease, drug response and environmental exposure.
The post-apoptotic fate of RNAs identified through high-throughput sequencing of human hair.
No sample metadata fields
View SamplesMaize exhibits levels of structural variation (SV) of non-repeat sequences that are unprecedented among higher eukaryotes. This SV includes hundreds of copy number variants (CNVs) and thousands of presence/absence variants (PAVs). Many of the PAVs contain intact, expressed, single-copy genes that are present in one haplotype but absent from another. The goal of this project is to test the hypothesis that differences in gene copy number (both gains and losses) contribute to the extraordinary phenotypic diversity and plasticity of maize. Maize is a good model for these studies because it exhibits a rapid decay of linkage disequilibrium (LD) and because a draft genome sequence of the B73 inbred and mapping populations are available. As a first step, the "Zeanome", a near-complete set of genes present in B73, other maize lines and the wild ancestor of maize (teosinte), is being defined using transcriptomic data.
No associated publication
No sample metadata fields
View SamplesNo description.
No associated publication
Cell line
View SamplesRNA-seq transcriptome profiles of genetically fate-mapped serotonin neurons, manually sorted from multiple anatomic domains, at both population and single cell resolution.
No associated publication
Sex, Specimen part, Cell line
View SamplesHeterosis which is the improved vigor of F1-hybrids compared to their parents is widely exploited in maize (Zea mays L.) breeding to produce elite hybrids of superior yield. The transcriptomes of the maize inbred lines B73 and Mo17 and their reciprocal hybrid offspring were surveyed in the meristematic zone, the elongation zone, cortex and stele tissues of primary roots, prior to the developmental manifestation of heterosis. Single parent expression (SPE) is consistent with the dominance model for heterosis in that it denotes genes that are expressed in only one parent but in both reciprocal hybrids. In primary root tissues, between 1,027 (elongation zone) and 1,206 (stele) SPE patterns were observed. As a consequence, hybrids displayed in each tissue >400 active genes more than either parent. Analysis of tissue-specific SPE dynamics revealed that 1,233 of 2,233 SPE genes displayed SPE in all tissues in which they were expressed while 1,000 SPE genes displayed in at least one tissue a non-SPE pattern. In addition, 64% (17,351/ 27,164) of all expressed genes were assigned to the two subgenomes which are the result of an ancient genome duplication. By contrast, only between 18 and 25% of the SPE genes were assigned to a subgenome suggesting that a disproportionate number of SPE genes are evolutionary young and emerged after genome duplication. We hypothesize that this phenomenon is associated with human selection of favorable maize genotypes which might primarily affect younger genes rather than genes whose functions have been conserved for millions of years.
Nonsyntenic genes drive highly dynamic complementation of gene expression in maize hybrids.
No sample metadata fields
View SamplesRNA-Seq of reciprocally crossed Black6 x CAST hybrid mouse tissues.
No associated publication
Sex, Cell line
View SamplesThe genomic distribution of trait-associated SNPs (TASs) discovered in genome-wide association studies (GWAS) can provide insight into the genetic architecture of complex traits and the design of future studies. Here we report on a maize GWAS that identified TASs underlying five quantitative traits measured across a large panel of samples and examine the characteristics of these TASs. A set of SNPs obtained via RNA sequencing (RNA-seq), most of which are located within annotated genes (~87%) were complemented with additional SNPs from the maize HapMap Project that contains approximately equal proportions of intragenic and intergenic SNPs. TASs were identified via a genome scan while controlling for polygenic background effects. The diverse functions of TAS-containing candidate genes indicate that complex genetic networks shape these traits. The vast majority of the TAS-containing candidate genes have dynamic expression levels among developmental stages. Overall, TASs explain 44~54% of the total phenotypic variation for these traits, with equal contributions from intra- and inter-genic TASs. Association of ligueless2 with upper leaf angle was implicated by two intragenic TASs; rough sheath1 was associated with leaf width by an upstream intergenic TAS; and Zea agamous5 was associated with days to silking by both intra- and inter-genic TASs. A large proportion (82%) of these TASs comes from noncoding regions, similar to findings from human diseases and traits. However, TASs were enriched in both intergenic (53%) and promoter 5kb (24%) regions, but under-represented in a set of nonsynonymous SNPs.
No associated publication
No sample metadata fields
View SamplesStudy on sex biased gene expression during multiple life stages and different strains in malaria vector Anopheles gambiae
No associated publication
Sex, Specimen part, Cell line, Treatment
View SamplesCirculating cell-free RNA in the blood provides a potential window into the health, phenotype, and developmental programs of a variety of human organs. We used high-throughput methods of RNA analysis such as microarrays and next-generation sequencing to characterize the global landscape of circulating RNA in human subjects. By focusing on tissue-specific genes, we were able to identify the relative contributions of these tissues to circulating RNA and monitor changes during tissue development and neurodegenerative disease states.
Noninvasive in vivo monitoring of tissue-specific global gene expression in humans.
No sample metadata fields
View Samples