Project description:RAD-seq genotyping of galactose-tolerant progeny from a backcross between disomic strain YPG3121 (chromosome XIII disome) and parent YO795
Project description:RAD-seq genotyping of galactose-tolerant progeny from a backcross between disomic strain YPG3104 (chromosome XIII disome) and parent YO796
Project description:Restriction site Associated DNA (RAD) tags are a genome-wide representation of every site of a particular restriction enzyme by short DNA tags. Most organisms segregate large numbers of DNA sequence polymorphisms that disrupt restriction sites, which allow RAD tags to serve as genetic markers spread at a high-density throughout the genome. Here, we demonstrate the applicability of RAD markers for both individual and bulk-segregant genotyping. First, we show that these markers can be identified and typed on pre-existing microarray formats. Second, we present a method that uses RAD marker DNA to rapidly produce a low-cost microarray genotyping resource that can be used to efficiently identify and type thousands of RAD markers. We demonstrate the utility of the former approach by using a tiling path array for the fruit fly to map a recombination breakpoint, and the latter approach by creating and utilizing an enriched RAD marker array for the threespine stickleback. The high number of RAD markers enabled localization of a previously identified region, as well as a second novel region also associated with the lateral plate phenotype. Taken together, our results demonstrate that RAD markers, and the method to develop a RAD marker microarray resource, allow high-throughput, high-resolution genotyping in both model and non-model systems. Keywords: microarray genotyping
Project description:Aspergillus flavus and A. parasiticus are two of the most important aflatoxin-producing species that contaminate agricultural commodities worldwide. Both species are heterothallic and undergo sexual reproduction in laboratory crosses. Here, we examine the possibility of interspecific matings between A. flavus and A. parasiticus. These species can be distinguished morphologically and genetically, as well as by their mycotoxin profiles. Aspergillus flavus produces both B aflatoxins and cyclopiazonic acid (CPA), B aflatoxins or CPA alone, or neither mycotoxin; Aspergillus parasiticus produces B and G aflatoxins or the aflatoxin precursor O-methylsterigmatocystin, but not CPA. Only four out of forty-five attempted interspecific crosses between compatible mating types of A. flavus and A. parasiticus were fertile and produced viable ascospores. Single ascospore strains from each cross were isolated and were shown to be recombinant hybrids using multilocus genotyping and array comparative genome hybridization. Conidia of parents and their hybrid progeny were haploid and predominantly monokaryons and dikaryons based on flow cytometry. Multilocus phylogenetic inference showed that experimental hybrid progeny were grouped with naturally occurring A. flavus L strain and A. parasiticus. Higher total aflatoxin concentrations in some F1 progeny strains compared to midpoint parent aflatoxin levels indicate synergism in aflatoxin production; moreover, three progeny strains synthesized G aflatoxins that were not produced by the parents, and there was evidence of putative allopolyploidization in one strain. These results suggest that hybridization is an important diversifying force resulting in the genesis of novel toxin profiles in these agriculturally important species.
Project description:Cryptococcus neoformans is a ubiquitous free-living soil yeast and opportunistic pathogen that causes ~223,100 cases of cryptococcal meningitis per year, killing over 180,000 people. The pathogenicity of C. neoformans relies on its adaptation to the host conditions. An important difference between its natural environment and the mammalian host is the concentration of CO2. CO2 levels in the host fluctuate around 5%, which is ~125-fold higher than in ambient air. We recently found that while clinical isolates are tolerant to host levels ofCO2, many environmental isolates are CO2-sensitive and virulence-attenuated in animal models. The genetic basis responsible for cryptococcal adaptation to high levels of CO2 is unknown. Here, we utilized quantitative trait loci (QTL) mapping with 374 progeny from a cross between a CO2-tolerant clinical isolate and a CO2-sensitive environmental isolate to identify genetic regions regulating CO2 tolerance. To identify specific quantitative trait genes (QTGs), we applied fine mapping through backcrossing and bulk segregant analysis coupled with pooled genome sequencing of near-isogenic progeny but with distinct tolerance levels to CO2. The roles of the identified QTGs in CO2 tolerance were verified by targeted gene deletion. We further demonstrated that virulence levels among near-isogenic strains in a murine model of cryptococcosis correlate with their levels of CO2 tolerance. Moreover, we discovered that sensitive strains may adapt in vivo to become more tolerant to increased CO2 levels and more virulent. These findings highlight the underappreciated role of the host CO2 tolerance and its importance in the ability of an opportunistic environmental pathogen to cause disease.
Project description:IL-33 is constitutively expressed in many epithelial tissues at steady state and signals through the receptor, ST2. IL-33 is released upon tissue injury and functions as an endogenous danger signal to alert the immune system to tissue damage. Here we investigate the physiological role of the IL-33/ST2 axis in skin homeostasis and cancer development. We show that expression of IL-33 differentiates malignant from normal/benign human tissues and that in mouse models of cutaneous squamous cell carcinoma the IL-33/ST2 axis protects against carcinogenesis. Tissue Treg are the predominant cells expressing ST2 in the skin and localise around the hair follicle and IL-33+ epithelial cells (EC). Adoptive transfer experiments demonstrate that skin Treg regulate EC differentiation, minimizes mutational load and retrains cancer development following exposure to an environmental carcinogen. Our findings indicate an important role for direct EC-Treg cross-talk as an early checkpoint to contain tissue damage and carcinogenesis.
Project description:We profiled gene expression in hypothalamus tissue from F2 progeny from a cross between the outbred M16 (selectively bred for rapid weight gain) and ICR (control) mouse strains. We developed a framework for reconstructing tissue-to-tissue coexpression networks between genes in hypothalamus, liver or hypothalamus tissues that are independent of networks constructed from single tissue analyses. The subnetworks we identify as specific to tissue-to-tissue interactions associate with multiple obesity-relevant biological functions like circadian rhythm, energy balance, stress response, or immune response. Keywords: Tissue profiling in a mouse F2 cross.
Project description:We profiled gene expression in liver tissue from F2 progeny from a cross between the outbred M16 (selectively bred for rapid weight gain) and ICR (control) mouse strains. We developed a framework for reconstructing tissue-to-tissue coexpression networks between genes in hypothalamus, liver or liver tissues that are independent of networks constructed from single tissue analyses. The subnetworks we identify as specific to tissue-to-tissue interactions associate with multiple obesity-relevant biological functions like circadian rhythm, energy balance, stress response, or immune response. Keywords: Tissue profiling in a mouse F2 cross.
Project description:We profiled gene expression in adipose tissue from F2 progeny from a cross between the outbred M16 (selectively bred for rapid weight gain) and ICR (control) mouse strains. We developed a framework for reconstructing tissue-to-tissue coexpression networks between genes in hypothalamus, adipose or adipose tissues that are independent of networks constructed from single tissue analyses. The subnetworks we identify as specific to tissue-to-tissue interactions associate with multiple obesity-relevant biological functions like circadian rhythm, energy balance, stress response, or immune response. Keywords: Tissue profiling in a mouse F2 cross.