How is the Human Genome Project doing, and what have we learned so far?

Genetics of Type 2 Diabetes: Past, Present, and Future

Diabetes has reached epidemic proportions worldwide. Currently, approximately 537 million adults (20–79 years) have diabetes, and the total number of people with diabetes is continuously increasing. Diabetes includes several subtypes. About 80% of all cases of diabetes are type 2 diabetes (T2D). T2D is a polygenic disease with an inheritance ranging from 30 to 70%. Genetic and environment/lifestyle factors, especially obesity and sedentary lifestyle, increase the risk of T2D. In this review, we discuss how studies on the genetics of diabetes started, how they expanded when genome-wide association studies and exome and whole-genome sequencing became available, and the current challenges in genetic studies of diabetes. T2D is heterogeneous with respect to clinical presentation, disease course, and response to treatment, and has several subgroups which differ in pathophysiology and risk of micro- and macrovascular complications. Currently, genetic studies of T2D focus on these subgroups to find the best diagnoses and treatments for these patients according to the principles of precision medicine.

Applications of Deep-Learning in Exploiting Large-Scale and Heterogeneous Compound Data in Industrial Pharmaceutical Research

In recent years, the development of high-throughput screening (HTS) technologies and their establishment in an industrialized environment have given scientists the possibility to test millions of molecules and profile them against a multitude of biological targets in a short period of time, generating data in a much faster pace and with a higher quality than before. Besides the structure activity data from traditional bioassays, more complex assays such as transcriptomics profiling or imaging have also been established as routine profiling experiments thanks to the advancement of Next Generation Sequencing or automated microscopy technologies. In industrial pharmaceutical research, these technologies are typically established in conjunction with automated platforms in order to enable efficient handling of screening collections of thousands to millions of compounds. To exploit the ever-growing amount of data that are generated by these approaches, computational techniques are constantly evolving. In this regard, artificial intelligence technologies such as deep learning and machine learning methods play a key role in cheminformatics and bio-image analytics fields to address activity prediction, scaffold hopping, de novo molecule design, reaction/retrosynthesis predictions, or high content screening analysis. Herein we summarize the current state of analyzing large-scale compound data in industrial pharmaceutical research and describe the impact it has had on the drug discovery process over the last two decades, with a specific focus on deep-learning technologies.

[Human genome project: a federator program of genomic medicine]

The Human Genome Project improves our understanding of the molecular genetics basis of the inherited and complex diseases such as diabetes, schizophrenia, and cancer. Information from the human genome sequence is essential for several antenatal and neonatal screening programmes. The new genomic tools emerging from this project have revolutionized biology and medicine and have transformed our understanding of health and the provision of healthcare. Its implications pervade all areas of medicine, from disease prediction and prevention to the diagnosis and treatment of all forms of disease. Increasingly, it will be possible to drive predisposition testing into clinical practice, to develop new treatments or to adapt available treatments more specifically to an individual's genetic make-up. This genomic information should transform the traditional medications that are effective for every members of the population to personalized medicine and personalized therapy. The pharmacogenomics could give rise to a new generation of highly effective drugs that treat causes, not just symptoms.

Lentivirus and foamy virus vectors: novel gene therapy tools

The aim of gene therapy is to modify the genetic material of living cells to achieve therapeutic benefit. Gene therapy involves the insertion of a functional gene into a cell, to replace an absent or defective gene, or to fight an infectious agent or a tumour. At present, a wide variety of somatic tissues are being explored for the introduction of foreign genes with a view towards treatment. A prime requirement for successful gene therapy is the sustained expression of the therapeutic gene without any adverse effect on the recipient. A highly desirable vector would be generated at high titres, integrate into target cells (including non-dividing cells) and have little or no associated immune reactions. Lentiviruses have the ability to infect dividing and non-dividing cells and, therefore, constitute ideal candidates for development of vectors for gene therapy. This review presents a description of available lentiviral vectors, including vector design, applications to disease treatment and safety considerations. In addition, general aspects of the biology of lentiviruses with relevance to vector development will be discussed. Recent investigations have revealed that foamy viruses, another group of retroviruses, are also capable of infecting non-dividing cells. Thus, foamy virus vectors are actively being developed in parallel to lentivirus vectors. This review will also include various aspects of the biology of foamy viruses with relevance to vector development.

A library-based bioinformatics services program

Support for molecular biology researchers has been limited to traditional library resources and services in most academic health sciences libraries. The University of Washington Health Sciences Libraries have been providing specialized services to this user community since 1995. The library recruited a Ph.D. biologist to assess the molecular biological information needs of researchers and design strategies to enhance library resources and services. A survey of laboratory research groups identified areas of greatest need and led to the development of a three-pronged program: consultation, education, and resource development. Outcomes of this program include bioinformatics consultation services, library-based and graduate level courses, networking of sequence analysis tools, and a biological research Web site. Bioinformatics clients are drawn from diverse departments and include clinical researchers in need of tools that are not readily available outside of basic sciences laboratories. Evaluation and usage statistics indicate that researchers, regardless of departmental affiliation or position, require support to access molecular biology and genetics resources. Centralizing such services in the library is a natural synergy of interests and enhances the provision of traditional library resources. Successful implementation of a library-based bioinformatics program requires both subject-specific and library and information technology expertise.

A genetic strategy to eliminate self-activator baits prior to high-throughput yeast two-hybrid screens

Large-scale sequencing projects have predicted high numbers of gene products for which no functional information is yet available. Hence, large-scale projects, such as gene knockouts, gene expression profiles, and protein-interaction mapping, are currently under way to initiate the understanding of the function of these gene products. The high-throughput strategies that are currently being developed to generate protein-interaction maps include automated versions of the yeast two-hybrid system. These strategies rely on the large-scale construction of DNA-binding domain/protein-of-interest hybrid constructs (DB-X baits). An inherent problem of large-scale two-hybrid systems is that a high percentage of cloned sequences encode polypeptides that, when fused to DB, can activate transcription in the absence of any two-hybrid-interacting partner protein. Here, we describe and validate a genetic strategy that efficiently eliminates such self-activator baits prior to screening procedures. The strategy is based on a negative-growth selection and is compatible with high-throughput settings.

Detection of single-nucleotide polymorphisms with the WAVE DNA fragment analysis system

As the Human Genome Project is generating an avalanche of genetic information, molecular researchers and clinical practitioners are setting new criteria for evaluation of the links between newly discovered gene mutations and human disorders. These requirements necessitate the development of highly accurate and yet rapid automated systems for genetic testing. We describe the detection of a single nucleotide polymorphism (SNP) on the human Y chromosome with the fully automated, sensitive, and rapid system WAVE designed for DNA fragment analysis. This new technology, based on temperature-modulated liquid chromatography and a high-resolution matrix, offers new dimensions to the molecular biology research. The versatility of the WAVE makes the equipment a universal molecular biology stations for clinical and research facilities. The key aspects to setting the operating parameters are discussed.

DNA microarray technology: the anticipated impact on the study of human disease

One can imagine that, one day, there will be a general requirement that relevant array data be deposited, at the time of publication of manuscripts in which they are described, into a single site made available for the storage and analysis of array data (modeled after the GenBank submission requirements for DNA sequence information). With this system in place, one can anticipate a time when data from thousands of gene expression experiments will be available for meta-analysis, which has the potential to balance out artifacts from many individual studies, thus leading to more robust results and subtle conclusions. This will require that data adhere to some type of uniform structure and format that would ideally be independent of the particular expression technology used to generate it. The pros and cons of various publication modalities for these large electronic data sets have been discussed elsewhere [12], but, practical difficulties aside, general depositing must occur for this technology to reach the broadest range of investigators. Finally, as mentioned at the beginning of this review, it is unfortunate that this important research tool remains largely restricted to a few laboratories that have developed expertise in this area and to a growing number of commercial interests. Ultimately the real value of microarray technology will only be realized when this approach is generally available. It is hoped that issues including platforms, instrumentation, clone availability, and patents [20] will be resolved shortly, making this technology accessible to the broadest range of scientists at the earliest possible moment.

A genome search identifies major quantitative trait loci on human chromosomes 3 and 4 that influence cholesterol concentrations in small LDL particles

Small, dense LDL particles are associated with increased risk of cardiovascular disease. To identify the genes that influence LDL size variation, we performed a genome-wide screen for cholesterol concentrations in 4 LDL size fractions. Samples from 470 members of randomly ascertained families were typed for 331 microsatellite markers spaced at approximately 15 cM intervals. Plasma LDLs were resolved by using nondenaturing gradient gel electrophoresis into 4 fraction sizes (LDL-1, 26.4 to 29.0 nm; LDL-2, 25.5 to 26.4 nm; LDL-3, 24.2 to 25.5 nm; and LDL-4, 21.0 to 24.2 nm) and cholesterol concentrations were estimated by staining with Sudan Black B. Linkage analyses used variance component methods that exploited all of the genotypic and phenotypic information in the large extended pedigrees. In multipoint linkage analyses with quantitative trait loci for the 4 fraction sizes, only LDL-3, a fraction containing small LDL particles, gave peak multipoint log10 odds in favor of linkage (LOD) scores that exceeded 3.0, a nominal criterion for evidence of significant linkage. The highest LOD scores for LDL-3 were found on chromosomes 3 (LOD=4.1), 4 (LOD=4.1), and 6 (LOD=2.9). In oligogenic analyses, the 2-locus LOD score (for chromosomes 3 and 4) increased significantly (P=0.0012) to 6.1, but including the third locus on chromosome 6 did not significantly improve the LOD score (P=0.064). Thus, we have localized 2 major quantitative trait loci that influence variation in cholesterol concentrations of small LDL particles. The 2 quantitative trait loci on chromosomes 3 and 4 are located in regions that contain the genes for apoD and the large subunit of the microsomal triglyceride transfer protein, respectively.

Expression profiling in cancer using cDNA microarrays

Currently there are over 1,000,000 human expressed sequence tag (EST) sequences available on the public database, representing perhaps 50-90% of all human genes. The cDNA microarray technique is a recently developed tool that exploits this wealth of information for the analysis of gene expression. In this method, DNA probes representing cDNA clones are arrayed onto a glass slide and interrogated with fluorescently labeled cDNA targets. The power of the technology is the ability to perform a genome-wide expression profile of thousands of genes in one experiment. In our review we describe the principles of the microarray technology as applied to cancer research, summarize the literature on its use so far, and speculate on the future application of this powerful technique.

Missense mutations in disease genes: a Bayesian approach to evaluate causality

The problem of interpreting missense mutations of disease-causing genes is an increasingly important one. Because these point mutations result in alteration of only a single amino acid of the protein product, it is often unclear whether this change alone is sufficient to cause disease. We propose a Bayesian approach that utilizes genetic information on affected relatives in families ascertained through known missense-mutation carriers. This method is useful in evaluating known disease genes for common disease phenotypes, such as breast cancer or colorectal cancer. The posterior probability that a missense mutation is disease causing is conditioned on the relationship of the relatives to the proband, the population frequency of the mutation, and the phenocopy rate of the disease. The approach is demonstrated in two cancer data sets: BRCA1 R841W and APC I1307K. In both examples, this method helps establish that these mutations are likely to be disease causing, with Bayes factors in favor of causality of 5.09 and 66.97, respectively, and posterior probabilities of .836 and .985. We also develop a simple approximation for rare alleles and consider the case of unknown penetrance and allele frequency.

Transcriptional sequencing: A method for DNA sequencing using RNA polymerase

We have developed a sequencing method based on the RNA polymerase chain termination reaction with rhodamine dye attached to 3'-deoxynucleoside triphosphate (3'-dNTP). This method enables us to conduct a rapid isothermal sequencing reaction in <30 min, to reduce the amount of template required, and to do PCR direct sequencing without the elimination of primers and 2'-dNTP, which disturbs the Sanger sequencing reaction. An accurate and longer read length was made possible by newly designed four-color dye-3'-dNTPs and mutated RNA polymerase with an improved incorporation rate of 3'-dNTP. This method should be useful for large-scale sequencing in genome projects and clinical diagnosis.

A ribozyme-mediated, gene "knockdown" strategy for the identification of gene function in zebrafish

The zebrafish system offers many unique opportunities for the study of molecular biology. To date, only random mutagenesis, and not directed gene knockouts, have been demonstrated in this system. To more fully develop the potential of the zebrafish system, an approach to effectively inhibit the expression of any targeted gene in the developing zebrafish embryo has been developed. This approach uses a transient, cytoplasmic, T7 expression system, injected into the fertilized zebrafish egg to rapidly produce high levels of a ribozyme directed against the mRNA encoded by the targeted gene to inhibit its expression. In a demonstration of this strategy, expression of the recessive dominant zebrafish no tail gene was effectively inhibited by using this strategy to yield a phenotype identical to that resulting from a known defective mutation in this same gene. This, ribozyme-mediated, message deletion strategy may have use in determining the function of genetic coding sequences of unknown function.

Fractionation, phosphorylation and ligation on oligonucleotide microchips to enhance sequencing by hybridization

Oligonucleotide microchips are manufactured by immobilizing presynthesized oligonucleotides within 0.1 x 0.1 x 0.02 mm or 1 x 1 x 0.02 mm polyacrylamide gel pads arranged on the surface of a microscope slide. The gel pads are separated from each other by hydrophobic glass spacers and serve as a kind of 'microtest tube' of 200 pl or 20 nl volume, respectively. Fractionation of single-stranded DNAs is carried out by their hybridization with chip pads containing immobilized 10mers. DNA extracted separately from each pad is transferred onto a sequencing chip and analyzed thereon. The chip, containing a set of 10mers, was enzymatically phosphorylated, then hybridized with DNA and ligated in a site-directed manner with a contiguously stacked 5mer. Several cycles of successive hybridization-ligation of the chip-bound 10mers with different contiguously stacked 5mers and hybridized with DNA were carried out to sequence DNA containing tetranucleotide repeats. Combined use of these techniques show significant promise for sequence comparison of homologous regions in different genomes and for sequence analysis of comparatively long DNA fragments or DNA containing internal repeats.

Molecular cloning of the interleukin-1 gene cluster: construction of an integrated YAC/PAC contig and a partial transcriptional map in the region of chromosome 2q13

Genes of the interleukin-1 (IL-1) gene cluster localized on chromosome 2q13 are implicated in many physiological and pathophysiological processes. We present here a high-resolution physical map of this region between markers D2S2008 and D2S4/PAX8. An integrated YAC/PAC contig and a partial transcriptional map were constructed by STS-constent mapping using the CEPH YAC library and three PAC libraries. A total of 3 YACs, 34 PACs, and 56 STSs were integrated: 33 newly generated probes to PAC end sequences, 9 polymorphic and 4 nonpolymorphic markers, 5 known genes, 4 expressed sequence tags, and 1 pseudogene. Within the map, a complete PAC contig of > 1 Mb encompasses the IL-1 gene cluster and PAX8, a paired-box-containing gene. This allowed us to define the transcriptional orientation of GLVR1, IL1B, and IL1RN and to show that PAX8 is localized outside the IL-1 gene cluster. FISH analysis localized PAC clones containing the IL-1 gene cluster to 2q12-q13. The data provide the basis for further characterization of the IL-1 gene cluster and for the construction of a sequence-ready PAC contig of this region.

Sequencing the human genome

By 2005, or sooner, the three billion code letters of a representative human genome will be known, along with the locations of all of its genes. Even today, however, the work is greatly accelerating identification of disease-related genes. One outcome will be tests for genetic components of risk in the majority of common illnesses. In the longer run, genetic discoveries will surely lead to new treatments.

Reinventing public health

This chapter is a review of the current state of public health in light of the social, political, economic, scientific, and technological changes buffeting the United States. As an assessment of progress in current public health efforts, we address the five major issues in public health for the 1990s raised by Breslow (8): reconstruction of public health; setting objectives for public health; from disease control to health promotion; determinants of health and health policy; continuing social inequities and their impacts on health; and the health implications of accelerating developments in technology. Finally, we look to the twenty-first century and provide five clear paths necessary to strengthen the capacity of public health agencies to protect and improve the health status of the population.

Individual variation in recombination among human males

Studies of recombination between the markers D6S291 and D6S109 in individuals by sperm typing provide direct evidence for significant variation in recombination among humans. A statistically significant difference in the recombination fraction (range 5.1%-11.2%) was detected among five donors. This variation could reflect polymorphisms in genes affecting recombination or in chromosome structure. Ignoring this variability in studies designed to examine the relationship between physical and genetic distances could lead to incorrect inferences. Individual variation in recombination makes it difficult to predict the recombination fraction for an interval in any particular individual. This could be important in certain genetic counseling situations.

Biodiversity, genomes, and DNA sequence databases

There are approximately 1.4 million organisms on this planet that have been described morphologically but there is no comparable coverage of biodiversity at the molecular level. Little more than 1% of the known species have been subject to any molecular scrutiny and eukaryotic genome projects have focused on a group of closely related model organisms. The past year, however, has seen an approximately 80% increase in the number of species represented in sequence databases and the completion of the sequencing of three prokaryotic genomes. Large-scale sequencing projects seem set to begin coverage of a wider range of the eukaryotic diversity, including green plants, microsporidians and diplomonads.

Genes responsible for human hereditary deafness: symphony of a thousand

Hearing loss is the most frequent sensory defect in humans. Dozens of genes may be responsible for the early onset forms of isolated deafness and several hundreds of syndromes with hearing loss have been described. Both the difficulties encountered by linkage analysis in families affected by isolated deafness and the paucity of data concerning the molecular components specifically involved in the peripheral auditory process, have long hampered the identification of genes responsible for hereditary hearing loss. Rapid progress is now being made in both fields. This should allow completion of major pieces of the jigsaw for understanding the development and function of the ear.

DNA sequencing using a four-color confocal fluorescence capillary array scanner

The design, construction and operation of a four-color capillary array electrophoresis scanner are presented. The use of sensitive energy transfer primers facilitates four-color detection of the DNA sequencing fragments following excitation at a single laser wavelength (488 nm). This scanner collects fluorescence data from up to 25 capillaries in parallel. The resulting four-color image files are automatically reduced to four-color line plots, and a base-calling program (Sax) is used to call the sequence. The performance of this system for DNA sequencing is demonstrated by examining twelve different motifs of the hypervariable region I of human mitochondrial (mt) DNA obtained from a Sierra Leone population.

Highly selective isolation of human DNAs from rodent-human hybrid cells as circular yeast artificial chromosomes by transformation-associated recombination cloning

Transformation-associated recombination (TAR) can be exploited in yeast to clone human DNAs. TAR cloning was previously accomplished using one or two telomere-containing vectors with a common human repeat(s) that could recombine with human DNA during transformation to generate yeast artificial chromosomes (YACs). On basis of the proposal that broken DNA ends are more recombinogenic than internal sequences, we have investigated if TAR cloning could be applied to the generation of circular YACs by using a single centromere vector containing various human repeats at opposite ends. Transformation with these vectors along with human DNA led to the efficient isolation of circular YACs with a mean size of approximately 150 kb. The circular YACs are stable and they can be easily separated from yeast chromosomes or moved into bacterial cells if the TAR vector contains an Escherichia coli F-factor cassette. More importantly, circular TAR cloning enabled the selective isolation of human DNAs from monochromosomal human-rodent hybrid cell lines. Although < 2% of the DNA in the hybrid cells was human, as much as 80% of transformants had human DNA YACs when a TAR cloning vector contained Alu repeats. The level of enrichment of human DNA was nearly 3000-fold. A comparable level of enrichment was demonstrated with DNA isolated from a radiation hybrid cell line containing only 5 Mb of human DNA. A high selectivity of human DNA cloning was also observed for linear TAR cloning with two telomere vectors. No human-rodent chimeras were detected among YACs generated by TAR cloning. The results with a circular TAR cloning vector or two vectors differed from results with a single-telomere vector in that the latter often resulted in a series of terminal deletions in linear YACs. This could provide a means for physical mapping of cloned material.

Sequence tag identification of intact proteins by matching tanden mass spectral data against sequence data bases

Molecular and fragment ion data of intact 8- to 43-kDa proteins from electrospray Fourier-transform tandem mass spectrometry are matched against the corresponding data in sequence data bases. Extending the sequence tag concept of Mann and Wilm for matching peptides, a partial amino acid sequence in the unknown is first identified from the mass differences of a series of fragment ions, and the mass position of this sequence is defined from molecular weight and the fragment ion masses. For three studied proteins, a single sequence tag retrieved only the correct protein from the data base; a fourth protein required the input of two sequence tags. However, three of the data base proteins differed by having an extra methionine or by missing an acetyl or heme substitution. The positions of these modifications in the protein examined were greatly restricted by the mass differences of its molecular and fragment ions versus those of the data base. To characterize the primary structure of an unknown represented in the data base, this method is fast and specific and does not require prior enzymatic or chemical degradation.

Identification and mapping of human cDNAs homologous to Drosophila mutant genes through EST database searching

Cross-species comparison is an effective tool used to identify genes and study their function in both normal and pathological conditions. We have applied the power of Drosophila genetics to the vast resource of human cDNAs represented in the expressed sequence tag (EST) database (dbEST) to identify novel human genes of high biological interest. Sixty-six human cDNAs showing significant homology to genes causing Drosophila mutant phenotypes were identified by screening dbEST using the "text string' option, and their map position was determined using both fluorescence in situ hybridization (FISH) and radiation hybrid mapping. Comparison between these genes and their putative partners in Drosophila may provide important insights into their function in mammals. Furthermore, integration of these genes into the transcription map of the human genome contributes to the positional candidate approach for disease gene identification.

S-pyridylethylation of intact polyacrylamide gels and in situ digestion of electrophoretically separated proteins: a rapid mass spectrometric method for identifying cysteine-containing peptides

In-gel proteolytic digestion of acrylamide-gel separated proteins is a method widely used for generating peptide fragments for the purpose of identifying proteins by Edman degratation, tandem mass spectrometry, and peptide-mass fingerprinting. However, it is well recognised for disulfide-bonded proteins electrophoresed under reducing conditions that if no precautions are taken to minimise disulfide bond formation during protein digestion or peptide isolation, complex peptide maps can result. Here, we describe an improved method for in-gel protein digestion. It consists of first reducing and S-pyridylethylating Coomassie Brilliant Blue R-250-stained proteins immobilised in the whole gel slab with dithiothreitol and 4-vinylpyridine, excising the individual stained and alkylated proteins, and then digesting them in situ in the gel matrix with trypsin or Achromobacter lyticus protease I. Peptide fragments generated in this manner are extracted from the gel piece and purified to homogeneity by a rapid (< or = 12 min) reversed-phase high performance liquid chromatography (HPLC) procedure, based upon conventional silica supports. Recoveries of peptides are increased by S-pyridylethylation of acrylamide-immobilised proteins prior to in-gel digestion. Further, the levels of gel-related contaminants, which otherwise result in suppression of sample signals during electrosprayionisation mass spectrometry, are greatly reduced by the reduction/alkylation step. Additionally, we demonstrate that S-beta-(4-pyridylethyl)-cysteine containing peptides can be readily identified during reversed-phase HPLC by absorbance at 254 nm, and during electrospray ionisation tandem mass spectrometry by the appearance of a characteristic-pyridylethyl fragment ion of 106 Da. The position of cysteine residues in a sequence can be determined as phenylthiohydantoin S-beta-(4-pyridylethyl)-cysteine during Edman degradation, and by tandem mass spectrometry.