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Characterization of the risk factors associated with variability in the clinical outcomes of COVID-19 is important. Our previous study using genomic data identified a potential role of calcium and lipid homeostasis in severe COVID-19. This study aimed to identify similar combinations of features (disease signatures) associated with severe disease in a separate patient population with purely clinical and phenotypic data. The PrecisionLife combinatorial analytics platform was used to analyze features derived from de-identified health records in the UnitedHealth Group COVID-19 Data Suite. The platform identified and analyzed 836 disease signatures in two cohorts associated with an increased risk of COVID-19 hospitalization. Cohort 1 was formed of cases hospitalized with COVID-19 and a set of controls who developed mild symptoms. Cohort 2 included Cohort 1 individuals for whom additional laboratory test data was available. We found several disease signatures where lower levels of lipids were found co-occurring with lower levels of serum calcium and leukocytes. Many of the low lipid signatures were independent of statin use and 50% of cases with hypocalcemia signatures were reported with vitamin D deficiency. These signatures may be attributed to similar mechanisms linking calcium and lipid signaling where changes in cellular lipid levels during inflammation and infection affect calcium signaling in host cells. This study and our previous genomics analysis demonstrate that combinatorial analysis can identify disease signatures associated with the risk of developing severe COVID-19 separately from genomic or clinical data in different populations. Both studies suggest associations between calcium and lipid signaling in severe COVID-19., Competing Interests: SD, MP, KT, VB, GM, MS, and SG were employed by company PrecisionLife Ltd. TH and KTHT were employed by company OptumLabs at UnitedHealth Group., (Copyright © 2021 Das, Pearson, Taylor, Bouchet, Møller, Hall, Strivens, Tzeng and Gardner.)

The SARS-CoV-2 pandemic has challenged researchers at a global scale. The scientific community's massive response has resulted in a flood of experiments, analyses, hypotheses, and publications, especially in the field of drug repurposing. However, many of the proposed therapeutic compounds obtained from SARS-CoV-2 specific assays are not in agreement and thus demonstrate the need for a singular source of COVID-19 related information from which a rational selection of drug repurposing candidates can be made. In this paper, we present the COVID-19 PHARMACOME, a comprehensive drug-target-mechanism graph generated from a compilation of 10 separate disease maps and sources of experimental data focused on SARS-CoV-2/COVID-19 pathophysiology. By applying our systematic approach, we were able to predict the synergistic effect of specific drug pairs, such as Remdesivir and Thioguanosine or Nelfinavir and Raloxifene, on SARS-CoV-2 infection. Experimental validation of our results demonstrate that our graph can be used to not only explore the involved mechanistic pathways, but also to identify novel combinations of drug repurposing candidates.

Genomic imprinting arises from allele-specific epigenetic modifications that are established during gametogenesis and that are maintained throughout somatic development. These parental-specific modifications include DNA methylation and post-translational modifications to histones, which create allele-specific active and repressive domains at imprinted regions. Through the use of a high-density genomic tiling array, we generated DNA and histone methylation profiles at 11 imprinted gene clusters in the mouse from DNA and from chromatin immunoprecipitated from sperm, heart, and cerebellum. Our analysis revealed that despite high levels of differential DNA methylation at non-CpG islands within these regions, imprinting control regions (ICRs) and secondary differentially methylated regions (DMRs) were identified by an overlapping pattern of H3K4 trimethylation (active chromatin) and H3K9 trimethylation (repressive chromatin) modifications in somatic tissue, and a sperm differentially methylated region (sDMR; sperm not equal somatic tissue). Using these features as a common signature of DMRs, we identified 11 unique regions that mapped to known imprinted genes, to uncharacterized genes, and to intergenic regions flanking known imprinted genes. A common feature among these regions was the presence of a CpG island and an array of tandem repeats. Collectively, this study provides a comprehensive analysis of DNA methylation and histone H3K4me3 and H3K9me3 modifications at imprinted gene clusters, and identifies common epigenetic and genetic features of regions regulating genomic imprinting.

A concerted effort to develop myriad new phenotypic alleles through mutagenesis programs presents new challenges for the biomedical community and for the informatics infrastructure needed to support this work. To handle and co-ordinate large programs of treatment, breeding, and sequential or longitudinal testing for a variety of obvious and subtle traits requires sophisticated data management software. Further, trait analyses, heritability testing, and animal availability and status must be captured and disseminated to the wider community. The Mouse Genome Database (MGD) will serve as the central integration point for the various mutagenesis programs, registering new alleles, providing accession identifiers, and capturing phenotypic descriptions. In addition, MGD will provide public access to unified searches over all alleles with links to the centres of origin for detailed testing data.

With the completion of the first draft of the human genome sequence, the next major challenge is assigning function to genes. One approach is genome-wide random chemical mutagenesis, followed by screening for mutant phenotypes of interest and subsequent mapping and identification of the mutated genes in question. We (a consortium made up of GlaxoSmithKline, the MRC Mammalian Genetics Unit and Mouse Genome Centre, Harwell, Imperial College, London, and the Royal London Hospital) have used ENU mutagenesis in the mouse for the rapid generation of novel mutant phenotypes for use as animal models of human disease and for gene function assignment (Nolan et al., 2000). As of 2003, 35,000 mice have been produced to date in a genome-wide screen for dominant mutations and screened using a variety of screening protocols. Nearly 200 mutants have been confirmed as heritable and added to the mouse mutant catalogue and, overall, we can extrapolate that we have recovered over 700 mutants from the screening programme. For further information on the project and details of the data, see http://www.mgu.har.mrc.ac.uk/mutabase.

A comprehensive gene-based map of a genome is a powerful tool for genetic studies and is especially useful for the positional cloning and positional candidate approaches. The availability of gene maps for multiple organisms provides the foundation for detailed conserved-orthology maps showing the correspondence between conserved genomic segments. These maps make it possible to use cross-species information in gene hunts and shed light on the evolutionary forces that shape the genome. Here we report a radiation hybrid map of mouse genes, a combined project of the Whitehead Institute/Massachusetts Institute of Technology Center for Genome Research, the Medical Research Council UK Mouse Genome Centre, and the National Center for Biotechnology Information. The map contains 11,109 genes, screened against the T31 RH panel and positioned relative to a reference map containing 2,280 mouse genetic markers. It includes 3,658 genes homologous to the human genome sequence and provides a framework for overlaying the human genome sequence to the mouse and for sequencing the mouse genome.

The Del(13)Svea36H deletion was recovered from a radiation mutagenesis experiment and represents a valuable resource for investigating gene content and function at this region of mouse Chromosome (Chr) 13 and human Chr 6p21.3-23 and 6p25. In this paper we examine the physical extent of chromosome loss and construct an integrated genetic and radiation hybrid map of the deleted segment. We show that embryos which are homozygous for the deletion die at or before implantation and that heterozygotes are subviable, with a substantial proportion of carriers dying after mid-gestation but before weaning. The majority of viable carriers exhibit a variety of phenotypes including decreased size, eyes open at birth, corneal opacity, tail kinks, and craniofacial abnormalities. Both the heterozygous viability and the penetrance of the visible phenotypes vary with genetic background.

This paper is aimed principally at bioinformaticians and biologists as an introduction to recent advances in mouse mutagenesis, concentrating on genome-wide screens utilising the powerful mutagen N-ethyl-N-nitroso-urea (ENU). It contains a brief background to the underlying genetics as well as details of the practical aspects of organisation and data capture for such projects.

As the human genome project approaches completion, the challenge for mammalian geneticists is to develop approaches for the systematic determination of mammalian gene function. Mouse mutagenesis will be a key element of studies of gene function. Phenotype-driven approaches using the chemical mutagen ethylnitrosourea (ENU) represent a potentially efficient route for the generation of large numbers of mutant mice that can be screened for novel phenotypes. The advantage of this approach is that, in assessing gene function, no a priori assumptions are made about the genes involved in any pathway. Phenotype-driven mutagenesis is thus an effective method for the identification of novel genes and pathways. We have undertaken a genome-wide, phenotype-driven screen for dominant mutations in the mouse. We generated and screened over 26,000 mice, and recovered some 500 new mouse mutants. Our work, along with the programme reported in the accompanying paper, has led to a substantial increase in the mouse mutant resource and represents a first step towards systematic studies of gene function in mammalian genetics.

Systematic approaches to mouse mutagenesis will be vital for future studies of gene function. We have begun a major ENU mutagenesis program incorporating a large genome-wide screen for dominant mutations. Progeny of ENU-mutagenized mice are screened for visible defects at birth and weaning, and at 5 weeks of age by using a systematic and semi-quantitative screening protocol-SHIRPA. Following this, mice are screened for abnormal locomotor activity and for deficits in prepulse inhibition of the acoustic startle response. Moreover, in the primary screen, blood is collected from mice and subjected to a comprehensive clinical biochemical analysis. Subsequently, secondary and tertiary screens of increasing complexity can be used on animals demonstrating deficits in the primary screen. Frozen sperm is archived from all the male mice passing through the screen. In addition, tail tips are stored for DNA. Overall, the program will provide an extensive new resource of mutant and phenotype data to the mouse and human genetics communities at large. The challenge now is to employ the expanding mouse mutant resource to improve the mutant map of the mouse. An improved mutant map of the mouse will be an important asset in exploiting the growing gene map of the mouse and assisting with the identification of genes underlying novel mutations-with consequent benefits for the analysis of gene function and the identification of novel pathways.

The increasing use of high-throughput methods for the production of biologically important information and the increasing diversity of that information pose considerable bioinformatics challenges. These challenges will be met by implementing electronic data management systems not only to capture the data, but increasingly to provide a platform for data integration and mining as we enter the post-genomic era. We discuss the design and implementation of such a data capture system, 'Mutabase', as a model of how such electronic systems might be designed and implemented. Mutabase was created in support of a large-scale, phenotype-driven mouse mutagenesis program at MRC Mammalian Genetics Unit, Harwell, in collaboration with SmithKline Beecham Pharmaceuticals, Queen Mary and Westfield College, London, and Imperial College of Science, Technology and Medicine, London. The aim of this mutagenesis project is to make a significant contribution to the existing mouse mutant resource, closing the phenotype gap and providing many more models for fundamental research and disease modeling. Mutabase records experimental details at the 'point of generation' and provides a number of dissemination and analysis tools for the experimental data, as well as providing a means of assessing various aspects of progress of the program. Mutabase uses a hypertext-based interface to provide interaction between a number of intranet-based client workstations and a central industrial strength database. Mutabase utilizes a variety of techniques in order to implement the user interface system including Perl/CGI, Java Servlets, and an experimental CORBA server. We discuss the relative merits of these methods in the context of the need to provide sound informatics approaches for the support of systematic mutagenesis programs.

A physical map of the mouse genome is an essential tool for both positional cloning and genomic sequencing in this key model system for biomedical research. Indeed, the construction of a mouse physical map with markers spaced at an average interval of 300 kb is one of the stated goals of the Human Genome Project. Here we report the results of a project at the Whitehead Institute/MIT Center for Genome Research to construct such a physical map of the mouse. We built the map by screening sequenced-tagged sites (STSs) against a large-insert yeast artificial chromosome (YAC) library and then integrating the STS-content information with a dense genetic map. The integrated map shows the location of 9,787 loci, providing landmarks with an average spacing of approximately 300 kb and affording YAC coverage of approximately 92% of the mouse genome. We also report the results of a project at the MRC UK Mouse Genome Centre targeted at chromosome X. The project produced a YAC-based map containing 619 loci (with 121 loci in common with the Whitehead map and 498 additional loci), providing especially dense coverage of this sex chromosome. The YAC-based physical map directly facilitates positional cloning of mouse mutations by providing ready access to most of the genome. More generally, use of this map in addition to a newly constructed radiation hybrid (RH) map provides a comprehensive framework for mouse genomic studies.

X-linked dominant disorders that are exclusively lethal prenatally in hemizygous males have been described in human and mouse. None of the genes responsible has been isolated in either species. The bare patches (Bpa) and striated (Str) mouse mutations were originally identified in female offspring of X-irradiated males. Subsequently, additional independent alleles were described. We have previously mapped these X-linked dominant, male-lethal mutations to an overlapping region of 600 kb that is homologous to human Xq28 (ref. 4) and identified several candidate genes in this interval. Here we report mutations in one of these genes, Nsdhl, encoding an NAD(P)H steroid dehydrogenase-like protein, in two independent Bpa and three independent Str alleles. Quantitative analysis of sterols from tissues of affected Bpa mice support a role for Nsdhl in cholesterol biosynthesis. Our results demonstrate that Bpa and Str are allelic mutations and identify the first mammalian locus associated with an X-linked dominant, male-lethal phenotype. They also expand the spectrum of phenotypes associated with abnormalities of cholesterol metabolism.

We describe progress in a continuing project aimed at the generation of an overlapping cosmid DNA clone map of the short arm of human chromosome 11. The automated procedures used to prepare DNA samples and the computerized data collection and recording systems are described. We also demonstrate the use of the clones as reagents for the rapid isolation of genomic DNAs containing smaller probed regions. We have isolated approximately 4700 human cosmid DNA clones from mouse/human hybrid cell lines that contain predominantly human chromosomal region 11p. Of the DNA in the cell lines, 60% is derived from this chromosomal region, and the remaining 40% is derived from regions of chromosomes 3, 19, and 20. A total of 4159 clones have been fingerprinted to identify potential overlaps, and we have developed 535 sets ("contigs"). Using random modeling, it is estimated that 65% of 11p must be contained in the analyzed cosmids. The database of clones has been used to identify single or overlapping clones from noncosmid DNA probes. Examples are presented. It is proposed that cosmid reference filters be distributed to requesting laboratories.