Project description:In the family Fagaceae, fertilization is delayed by several weeks to more than one year after pollination, leading to one- or two-year fruiting species depending on whether fruiting occurs in the same or the next year of flowering. Although delayed fertilization was recorded over a century ago, underlying mechanisms remain to be explored. To uncover the key genes associated with delayed fertilization, we obtain and analyze the comparative molecular phenology data over two years in one-year (Quercus glauca) and two-year fruiting species (Lithocarpus edulis).
Project description:In the family Fagaceae, fertilization is delayed by several weeks to more than one year after pollination, leading to one- or two-year fruiting species depending on whether fruiting occurs in the same or the next year of flowering. Although delayed fertilization was recorded over a century ago, underlying mechanisms remain to be explored. To uncover the key genes associated with delayed fertilization, we obtain and analyze the comparative molecular phenology data over two years in one-year (Quercus glauca) and two-year fruiting species (Lithocarpus edulis).
Project description:To identify novel mechanisms regulating allogeneic hematopoietic cell engraftment, we previously used a forward genetic approach and described identification, in mice, of the Bmgr5 bone marrow (BM) engraftment quantitative trait locus (QTL). This QTL confers dominant and large allele effects for engraftment susceptibility. It was localized to chromosome 16 by classical quantitative genetic techniques in a segregating backcross bred from susceptible BALB.K and resistant B10.BR mice. We now report verification of the Bmgr5 QTL using reciprocal chromosome 16 consomic strains. The BM engraftment phenotype in these consomic mice shows that Bmgr5 susceptibility alleles are not only sufficient but also indispensable for conferring permissiveness for allogeneic BM engraftment. Using panels of congenic mice, we resolved the Bmgr5 QTL into two separate subloci, termed Bmgr5a and Bmgr5b, each conferring permissiveness for the engraftment phenotype and both fine mapped to an interval amenable to positional cloning. Candidate Bmgr5 genes were then prioritized using whole exome DNA sequencing and microarray gene expression profiling. Further studies are needed to elucidate the genetic interaction between Bmgr5a and Bmgr5b and identify causative genes and underlying gene variants. This may lead to new approaches for overcoming the problem of graft rejection in clinical hematopoietic cell transplantation.
Project description:Myxococcus xanthus is a model organism for studying social behaviors and cell differentiation in bacteria. Upon nutrient depletion, M. xanthus cells initiate a developmental program that culminates in formation of spore-filled fruiting bodies and peripheral rods outside of fruiting bodies. Completion of this developmental program depends on fine-tuned spatial and temporal regulation of gene expression, intercellular communication, signaling by nucleotide-based second messengers, and motility. In order to understand stage-specific gene expression during growth and development, we extracted total RNA from vegetative cells (referred as 0 h of development) and from cells developed for 6, 12, 18 and 24 h under submerged conditions in two replicates.
Project description:Positional gene isolation requires either a local or global reference genome sequence or an inference of gene content based on conservation of synteny with a genomic model. In the large unsequenced genomes of the Triticeae cereals the latter, i.e. conservation of synteny with the rice and Brachypodium genomes, provides a powerful proxy for establishing local gene content and order. However, exploiting conservation of synteny requires 'homology bridges' between the model genome and the target region that contains a gene of interest. As effective homology bridges are generally the sequences of genetically mapped genes, increasing the density of mapped these genes around a target locus is an important step in the process. We used Bbulked Ssegregantte Aanalysis (BSA) of transcript abundance data to identify genes located in a specific region of the barley genome. The approach is valuable because only a relatively small proportion of barley genes are currently placed on a genetic map. We analyzed eQTL datasets from the reference Steptoe x Morex doubled haploid population and showed a strong association between differential gene expression and cis-regulation, with 83% of differentially expressed genes co-locating with their eQTL. We then performed bulked segregant analysis (BSA) by assembling allele-specific bulks pools based on the genotypes of individuals at the partial resistance QTL Rphq11. BSA identified a total of 411 genes as differentially expressed, including HvPHGPx, that was previously identified as being a promising candidate for Rphq11. The genetic location of 276 of these genes could be determined from both eQTL datasets and conservation of synteny, and 254 (92%) of these were located on the target chromosome. We conclude that identification of differential expression by BSA constitutes a novel method to identify genes located in specific regions of interest. The datasets obtained from such studies provide a high-profile repertoirerobust set of candidate genes for analysis and serve as valuable resources for targeted marker development and comparative mapping with other grass species.