SNP analysis to dissect human traits

Cross-disorder analysis of endometriosis and its comorbid diseases reveals shared genes and molecular pathways and proposes putative biomarkers of endometriosis

RESEARCH QUESTION

Women with endometriosis are considered to be at higher risk of several chronic diseases, such as autoimmune disorders, gynaecological cancers, asthma/atopic diseases and cardiovascular and inflammatory bowel diseases. Could the study of endometriosis-associated comorbidities help to identify potential biomarkers and target pathways of endometriosis?

DESIGN

A systematic review was performed to identify all possible endometriosis-associated comorbid conditions. Next, this list of disorders was coded into MeSH terms, and the gene expression profiles were downloaded from the Phenopedia database and subsequently analysed following a systems biology approach.

RESULTS

The results identified a group of 127 candidate genes that were recurrently expressed in endometriosis and its closest comorbidities and that were defined as 'endometriosis sibling disorders' (ESD). The enrichment analysis showed that these candidate genes are principally involved in immune and drug responses, hormone metabolism and cell proliferation, which are well-known hallmarks of endometriosis. The expression of ESD genes was then validated on independent sample cohorts (n = 207 samples), in which the involvement of 16 genes (AGTR1, BDNF, C3, CCL2, CD40, CYP17A1, ESR1, IGF1, IGF2, IL10, MMP1, MMP7, MMP9, PGR, SERPINE1 and TIMP2) in endometriosis was confirmed. Several of these genes harbour polymorphisms that associate to either endometriosis or its comorbid conditions.

CONCLUSIONS

The study results highlight the molecular processes underlying the aetiopathogenesis of endometriosis and its comorbid conditions, and identify putative endometriosis biomarkers.

Association between vitamin D receptor gene FokI and TaqI variants with autism spectrum disorder predisposition in Iranian population

BACKGROUND AND AIM

Autism spectrum disorder (ASD) is one of the neurodevelopmental and cognitive conditions that involves 1 in 160 children around the world. Several studies showed that there is a relationship between vitamin D receptor (VDR) gene polymorphisms with the neurodevelopmental behavioral disorders. In the current study, we aimed to highlight the association of VDR gene polymorphisms (FokI and TaqI) with the risk of autism in Birjand population.

MATERIAL AND METHODS

In this case-control study eighty-one patients recognized with ASD and one hundred-eight healthy controls were recruited to the study from 2017 to 2018. Genotyping was carried out by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) technique for all subjects.

RESULTS

Calculated odds ratio and P-value for the alleles of VDR gene FokI and TaqI variants between autistic patients and controls did not show a significant difference (P > 0.05). However, calculated homozygous recessive (tt) for TaqI polymorphism was statistically significant (P = 0.015) in control group and there was also statistically meaningful difference in both case and control groups in ft haplotype (P = 0.04).

CONCLUSION

These results provide preliminary evidence that genetic variants of the VDR gene (FokI and TaqI) might have a possible reduced risk of ASD occurrence in children. The additional examination is needed to acquire more decisive and precise results in this area.

Correlation between survivin polymorphism and acute leukemia of children

The correlation between the variations in the polymorphic sites of survivin, rs9904341C/G and rs8073069C/G, and the pathogenesis of acute leukemia, as well as the guiding significance in clinical practice were investigated. We enrolled a total of 182 children with acute leukemia and 200 healthy children as the subjects. In accordance with the case-control method, the polymerase chain reaction was carried out for genetic typing of the two polymorphic sites, rs9904341C/G and rs8073069C/G. In the case group and the healthy group, the frequencies of C and G alleles in rs9904341C/G of survivin were 59.3 and 41.7%, and 46.7 and 50.3%, respectively, and the pairwise comparison showed statistically significant differences (P=0.008). Additionally, the frequencies of genotypes, C/C, C/G and G/G, were 38.5 and 41.7%; 19.8 and 26.5%; 16.5 and 27.0% in the case group and the healthy group, respectively, and the differences in comparisons showed statistical significance (P=0.033). The genotype frequency of C/C in the case group was 38.5%, significantly higher than that in the healthy group (26.5%). Compared with C/C, the risk coefficient of leukemia in patients with genotypes of C/G or G/G was significantly decreased. In the case group and the healthy group, the frequencies of C and G alleles in rs8073069C/G of survivin were 30.5 and 69.5%; 27.7 and 72.3%, respectively, and the pairwise comparison showed no statistically significant differences (P=0.404). Additionally, the frequencies of genotypes, C/C, C/G and G/G, were 11 and 39.0%; 50.0 and 9.0%; 37.5 and 53.5% in the case group and the healthy group, respectively, and the differences in comparisons showed no statistical significance (P=0.62). Compared with the genotype of C/C, we found that the risk of leukemia was not affected in patients with genotypes of C/G and G/G. In conclusion, the SNP of rs9904341C/G in survivin may be correlated with the risk of acute leukemia, and compared with C/C genotype, patients with C/G or G/G may have a decreased risk of acute leukemia. In survivin, rs8073069C/G may have no correlation with the risk of acute leukemia.

Vitamin D Receptor Gene Polymorphisms Associated with Childhood Autism

Background: Autism spectrum disorder (ASD) is a group of heterogeneous, behaviorally defined disorders whereby currently no biological markers are common to all affected individuals. A deregulated immune response may be contributing to the etiology of ASD. The active metabolite of vitamin D₃ has an immunoregulatory role mediated by binding to the vitamin D receptor (VDR) in monocyte, macrophages, and lymphocytes. The effects of vitamin D and interaction with the VDR may be influenced by polymorphism in the VDR gene. Methods: Genetic association of four different VDR polymorphisms (Apa-I, Bsm-I, Taq-I, Fok-I) associated with susceptibility to the development of autism in children was investigated. Results: We uniquely found an association between the presence of the T allele at position Taq-I and presence of the a allele at position Apa-I of the VDR gene with decreased ASD incidence. There was also an association between female gender and the presence of the T allele. We found no statistical significant correlation between VDR single nucleotide polymorphisms (SNPs) and vitamin D₃ concentration in serum of ASD children. Conclusion: Genetic polymorphism in two SNP in VDR may be correlated with development of ASD symptoms by influencing functionality of vitamin D₃ metabolism, while vitamin D₃ levels were not significantly different between ASD and non-ASD children.

Influence of candidate polymorphisms on the dipeptidyl peptidase IV and μ-opioid receptor genes expression in aspect of the β-casomorphin-7 modulation functions in autism

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with population prevalence of approximately 60-70 per 10,000. Data shows that both opioid system function enhancement and opiate administration can result in autistic-like symptoms. Cow milk opioid peptides, including β-casomorphin-7 (BCM7, Tyr-Pro-Phe-Pro-Gly-Pro-Ile), affect the μ-opioid receptor (MOR) and are subjected to degradation resulting from the proline dipeptidyl peptidase IV (DPPIV, EC 3.4.14.5) enzyme activity. The presence of MOR and DPPIV activity are crucial factors determining biological activity of BCM7 in the human body. Our study examined the effect of β-casomorphin-7 on the MOR and DPPIV genes expression according to specific point mutations in these genes. In addition, we investigated frequency of A118G SNP in the MOR gene and rs7608798 of the DPPIV (A/G) gene in healthy and autistic children. Our research indicated correlation in DPPIV gene expression under the influence of BCM7 and hydrolyzed milk between healthy and ASD-affected children with genotype GG (P<0.0001). We also observed increased MOR gene expression in healthy children with genotype AG at polymorphic site A118G under influence of BCM7 and hydrolyzed milk. The G allele frequency was 0.09 in MOR gene and 0.68 in the DPPIV gene. But our results suggest no association between presence of the alleles G and A at position rs7608798 in DPPIV gene nor alleles A and G at position A118G of the MOR and increased incidence of ASD. Our studies emphasize the compulsion for genetic analysis in correlation with genetic factors affecting development and enhancement of autism symptoms.

Cloud computing-based TagSNP selection algorithm for human genome data

Single nucleotide polymorphisms (SNPs) play a fundamental role in human genetic variation and are used in medical diagnostics, phylogeny construction, and drug design. They provide the highest-resolution genetic fingerprint for identifying disease associations and human features. Haplotypes are regions of linked genetic variants that are closely spaced on the genome and tend to be inherited together. Genetics research has revealed SNPs within certain haplotype blocks that introduce few distinct common haplotypes into most of the population. Haplotype block structures are used in association-based methods to map disease genes. In this paper, we propose an efficient algorithm for identifying haplotype blocks in the genome. In chromosomal haplotype data retrieved from the HapMap project website, the proposed algorithm identified longer haplotype blocks than an existing algorithm. To enhance its performance, we extended the proposed algorithm into a parallel algorithm that copies data in parallel via the Hadoop MapReduce framework. The proposed MapReduce-paralleled combinatorial algorithm performed well on real-world data obtained from the HapMap dataset; the improvement in computational efficiency was proportional to the number of processors used.

A new method of diagnosing constitutional types based on vocal and facial features for personalized medicine

The aim of the present study is to develop an accurate constitution diagnostic method based solely on the individual's physical characteristics, irrespective of psychologic traits, characteristics of clinical medicine, and genetic factors. In this paper, we suggest a novel method for diagnosing constitutional types using only speech and face characteristics. Based on 514 subjects, the area under the receiver operating characteristics curve (AUC) values of classification models in age and gender groups ranged from 0.64 to 0.89. We identified significant features showing statistical differences among three constitutional types by performing statistical analysis. Also, we selected a compact and discriminative feature subset for constitution diagnosis in each age and gender group. Our method may support the direction of improved diagnosis prediction and will serve to develop a personal and automatic constitution diagnosis software for improvement of the effectiveness of prescribed medications and development of personalized medicine.

EphB4 gene polymorphism and protein expression in non-small-cell lung cancer

The objective of this study was to identify new diagnostic, prognostic or therapeutic molecules for non-small- cell lung cancer (NSCLC). We investigated the expression of EphB4, a tyrosine kinase receptor which has been shown to act as a tumor promoter in other cancers. Using immunohistochemistry, we visualized EphB4 expression in 28 samples of NSCLC and 12 samples of adjacent normal tissues. Additionally, we assessed a single-nucleotide polymorphism in EphB4 to determine its effect on protein expression. The correlation of both genotype and protein expression with disease severity was determined. EphB4 was expressed in 53.6% of patients with lung cancer, a significant increase compared to control lung samples (0.0%, P<0.05). Furthermore, EphB4 expression was correlated with differentiation, lymph node metastasis and TNM stage of tumors (P<0.05). Additionally, the polymorphism in EphB4 at rs314310 appeared to correspond to protein expression and disease susceptibility. While the frequencies of CC, CA and AA genotypes were not different between lung cancer patients and healthy controls, the frequencies of C and A alleles were significantly different between these groups (P<0.05). Further analysis showed that the positive rate of EphB4 expression in patients with the AA genotype was significantly higher compared to that in patients with other genotypes (P<0.05). Overexpression of EphB4 plays a role in the occurrence and development of NSCLC, and the polymorphism at rs314310 may predispose individuals to this disease.

A novel efficient dynamic programming algorithm for haplotype block partitioning

In this paper, a new efficient algorithm is presented for haplotype block partitioning based on haplotype diversity. In this algorithm, finding the largest meaningful block that satisfies the diversity condition is the main goal as an optimization problem. The algorithm can be performed in polynomial time complexity with regard to the number of haplotypes and SNPs. We apply our algorithm on three biological data sets from chromosome 21 in three different population data sets from HapMap data bulk; the obtained results show the efficiency and better performance of our algorithm in comparison with three other well known methods.

Do Estrogen Receptor beta Polymorphisms Play A Role in the Pharmacogenetics of Estrogen Signaling?

Estrogen hormones play critical roles in the regulation of many tissue functions. The effects of estrogens are primarily mediated by the estrogen receptors (ER) alpha and beta. ERs are ligand-activated transcription factors that regulate a complex array of genomic events that orchestrate cellular growth, differentiation and death. Although many factors contribute to their etiology, estrogens are thought to be the primary agents for the development and/or progression of target tissue malignancies. Many of the current modalities for the treatment of estrogen target tissue malignancies are based on agents with diverse pharmacology that alter or prevent ER functions by acting as estrogen competitors. Although these compounds have been successfully used in clinical settings, the efficacy of treatment shows variability. An increasing body of evidence implicates ERalpha polymorphisms as one of the contributory factors for differential responses to estrogen competitors. This review aims to highlight the recent findings on polymorphisms of the lately identified ERbeta in order to provide a functional perspective with potential pharmacogenomic implications.

Genetic variation in human disease and a new role for copy number variants

While complex diseases, such as inflammatory bowel disease, do not follow distinctive Mendelian inheritance patterns, there is now considerable evidence from twin and pedigree studies to show that there are significant genetic influences in the development of many such diseases. In times past, this type of information was considered to be interesting, and was used mainly to alert other members of the families that they may also be at increased risk of developing the disease. However, with the ability to evaluate the genetic basis of common disease, this information will have important consequences for the diagnosis, prevention and treatment of the disorder. The genetic basis for common disease is likely to be more complicated than we had previously anticipated, since we now recognise epigenetic causes of disease, and other subtle gene regulatory mechanisms. Copy number variants have been highlighted in this review, as being a phenomenon that we have known about for a long time, but that has not previously been clearly associated with human disease. As complex disease is related to changes in gene expression, any variation in the human genome that alters gene expression is now a candidate for being involved in the disease process.

Complex genetics of complex traits: the case of primary open-angle glaucoma

Glaucoma, which is a complex heterogeneous disease, presents an ideal case for genetic investigation. Primary open-angle glaucoma (POAG) is the commonest subtype and will be the focus of this review. When detected early, POAG is amenable to therapeutic intervention. Unfortunately, current population-based clinical screening lacks efficacy. If individuals with a genetic predisposition for developing POAG can be identified, then efficient and cost-effective population-based screening programs could be designed. Although considerable inroads have been made in understanding the natural history of POAG caused by mutations in the myocilin and optineurin genes, other POAG genes accounting for most cases remain to be identified. This review explores the genetic mechanisms that have been unequivocally linked to the glaucomatous process and then discusses potential avenues for future breakthroughs.

Smoking-gene interaction and disease development: relevance to pancreatic cancer and atherosclerosis

There is little doubt that cigarette smoking remains a major environmental health risk that humans are facing in the twenty-first century. Cigarette smokers are more likely to develop many forms of diseases than nonsmokers, including cancers and vascular diseases. With the availability of the human genome sequence, we become more aware of the genetic contributions to these common diseases, especially the interactive relations between environmental factors (e.g., smoking) and genes on disease susceptibility, development, and prognosis. Although smoking is responsible for up to 30% of pancreatic cancers and about 10% of cases are ascribed to genetic reasons, some genetic variants do not predispose carriers to disease development unless they are exposed to a specific adverse environment such as smoking. This smoke-gene interaction could potentially be responsible for most of the cases. Certain polymorphisms in genes such as CYP1A1 have been shown particularly sensitive to smoking-induced pathogenesis, including pancreatic cancer and atherosclerosis. We found that individuals with CYP1A1 CC genotype had a more than three fold increase in risk for severe coronary atherosclerosis when they smoked. Patients with endothelial nitric oxide synthase (eNOS) intron 4 27 repeat homozygotes were more likely to develop severe coronary stenosis when they smoked. On the other hand, DNA variants at the eNOS gene also dictate how smoking affects the expression of eNOS. We showed that GSTM1 deficiency was not involved in smoking-induced vascular diseases, but p53 polymorphisms tended to modify the disease severity in smokers. We are still at an early stage of defining the pairs and mechanisms of smoke-gene interaction, and this etiologic mechanism may hold great potential for risk assessment, treatment strategy, and prognostic predictions.

Estimating haplotype frequencies in pooled DNA samples when there is genotyping error

Background

Maximum likelihood estimates of haplotype frequencies can be obtained from pooled DNA using the expectation maximization (EM) algorithm. Through simulation, we investigate the effect of genotyping error on the accuracy of haplotype frequency estimates obtained using this algorithm. We explore model parameters including allele frequency, inter-marker linkage disequilibrium (LD), genotyping error rate, and pool size.

Results

Pool sizes of 2, 5, and 10 individuals achieved comparable levels of accuracy in the estimation procedure. Common marker allele frequencies and no inter-marker LD result in less accurate estimates. This pattern is observed regardless of the amount of genotyping error simulated.

Conclusion

Genotyping error slightly decreases the accuracy of haplotype frequency estimates. However, the EM algorithm performs well even in the presence of genotyping error. Overall, pools of 2, 5, and 10 individuals yield similar accuracy of the haplotype frequency estimates, while reducing costs due to genotyping.

An Alternative Way to Individualized Medicine: Psychological and Physical Traits of Sasang Typology

BACKGROUND

Disease susceptibility and drug response of individuals are presumed to be different depending on their personality traits. The Sasang typology, a traditional Korean medical typology, explains the individual differences of vulnerability to pathology and proposes guidelines for the safe and effective use of medical herbs depending on individual traits.

OBJECTIVE

The purpose of the present study was to evaluate psychologic and physical characteristics of Sasang types from the perspective of personality theory.

DESIGN

After determining the Sasang type of 79 college students based on the Questionnaire for the Sasang Constitution Classification, the psychologic and physical traits of each type were analyzed by the Meyers-Briggs Type Indicator (MBTI) and Bioelectrical Impedance Analysis, respectively.

RESULTS

Each of the Sasang types showed significantly different profiles based on the MBTI scores (generalized estimation equation, coefficient = 11.88, z = 2.13, p = 0.033) and could be distinctively classified based on their MBTI scores (discriminant analysis Wilks' lambda = 0.611, df = 8, chi(2) = 36.7, p < 0.001). Subjects with the So-Eum type (Introversion and Judging) and the So-Yang type (Extroversion and Perceiving) showed contrasting psychologic features. However, they had similar anthropometric characteristics. Subjects with Tae-Eum type had relatively higher body fat mass.

CONCLUSION

Current results demonstrated distinctive personality traits associated with Sasang types using reproducible psychometric and anthropometric instruments. With further study, the Sasang typology could serve as a scientific tool for individualized and integrative medicine.

New approaches to investigating heterogeneity in complex traits

Great advances in the field of genetics have been made in the last few years. However, resolving the complexity that underlies the susceptibility to many polygenic human diseases remains a major challenge to researchers. The fast increase in availability of genetic data and the better understanding of the clinical and pathological heterogeneity of many autoimmune diseases such as multiple sclerosis, but also Parkinson's disease, Alzheimer's disease, and many more, have changed our views on their pathogenesis and diagnosis, and begins to influence clinical management. At the same time, more powerful methods that allow the analysis of large numbers of genes and proteins simultaneously open opportunities to examine their complex interactions. Using multiple sclerosis as a prototype, we review here how new methodologies such as gene expression profiling can be exploited to gain insight into complex trait diseases.

Bioinformatics in neurosurgery

WITH THE COMPLETION of the Human Genome Project, the amount of molecular biological sequence data available in public databases has reached staggering proportions. Data continue to accumulate at an exponential rate in the postgenomic era. Compilation, storage, searching, sharing, studying, and transmitting of all these data present formidable challenges. To keep pace with this extant database, the science of bioinformatics (sometimes called computational biology) has evolved. Bioinformatics is the combination of biology and computers and usually involves the storage or analysis of molecular biological sequence data at either the deoxyribonucleic acid, ribonucleic acid, or protein (amino acid) level. Most bioinformatics tools are freely available on the Internet for use by investigators around the globe. The collective wisdom from bioinformatics databases worldwide will continue to spawn advances in the neurological sciences for generations to come. Neurosurgeons must be aware of the power and potential applications of bioinformatics for the analysis of neurosurgical diseases.

Genetic influence on cigarette-induced cardiovascular disease

Cigarette smoking as an addictive habit has accompanied human beings for more than 4 centuries. It is also one of the most potent and prevalent environmental health risks human beings are exposed to, and it is responsible for more than 1000 deaths each day in the United States. With recent research progress, it becomes clear that cigarette smoking can cause almost all major diseases prevalent today, such as cancer or heart disease. These detrimental effects are not only present in active smokers who choose the risk, but also to innocent bystanders, as passive smokers, who are exposed to cigarettes not-by-choice. While the cigarette-induced harm to human health is indiscriminate and severe, the degree of damage also varies from individual to individual. This intersubject variability in cigarette-induced pathologies is partly mediated by genetic variants of genes that may participate in detoxification process, eg, cytochrome P450 (CYP), cellular susceptibility to toxins, such as p53, or disease development. Through population studies, we have learned that certain CYP1A1 variants, such as Mspl polymorphism, may render the carriers more susceptible to cigarette-induced lung cancer or severe coronary atherosclerosis. The endothelial nitric oxide synthase intron 4 rare allele homozygotes are more likely to have myocardial infarction if they also smoke. In vitro experimental approach has further demonstrated that cigarettes may specifically regulate these genes in genotype-dependent fashion. While we still know little about genetic basis and molecular pathways for cigarette-induced pathological changes, understanding these mechanisms will be of great value in designing strategies to further reduce smoking in targeted populations, and to implement more effective measures in prevention and treatment of cigarette-induced diseases.

Techniques patents for SNP genotyping

Single nucleotide polymorphisms (SNPs) are the most abundant form of genetic variation in the human genome, accounting for more than 90% of all differences between individuals. Many complex phenotypes in humans have a significant genetic component and most of the variability is therefore likely to stem from differences in patterns of SNPs. Association studies involving the large-scale analysis of SNPs can help to identify genes affecting many human phenotype variations, including complex diseases and drug responses. SNPs therefore play a major role in all stages of the drug development process, from target identification through to clinical trials. SNPs are also the basis of pharmacogenomics, the tailoring of medicines to suit an individual's genome. Given the potential impact of SNPs on healthcare, the biotechnology industry has focussed urgently on the development of high-throughput methods for SNP genotyping. All genotyping methods are a mix and match of different allele discrimination and signal detection technologies and as such may represent the intellectual property of several individuals or organizations. In this review, we explore the patent issues surrounding SNP genotyping and how this is influencing large scale, commercially valuable projects involving SNPs.

Genotyping of Essential Hypertension Single-Nucleotide Polymorphisms by a Homogeneous PCR Method with Universal Energy Transfer Primers

Background: Human hypertension is a complex, multifactorial disease with a heritability of more than 30–50%. A genetic screening test based on analysis of multiple single-nucleotide polymorphisms (SNPs) to assess the likelihood of developing hypertension would be helpful for disease management.

Methods: Tailed allele-specific primers were designed to amplify by PCR six biallelic SNP loci [three in G protein-coupled receptor kinase type 4 (GRK4): R65L, A142V, and A486V; two in angiotensinogen: −6G→A and M235T; and one in aldosterone synthase: −344C→T] associated with essential hypertension. PCRs of SNP loci were coupled (via a common sequence of 21 nucleotide tails) to incorporate Universal Amplifluor™ primers labeled with fluorescein or sulforhodamine in a homogeneous format. Use of Amplifluors in SNP PCRs produced labeled amplicons, the fluorescence of which was quantified by a microplate reader and then analyzed via an Excel macro to provide genotypes for all six SNP loci. Unique restriction endonucleases were identified for five SNP loci that could independently confirm homogeneous PCR results when needed.

Results: We developed six homogeneous PCR assays that were set up, performed, and fluorometrically analyzed in 96-well microplates. Allele frequencies were determined for six SNPs in 60 Italian hypertensive patients and a control group of 60 normotensive persons. A significant correlation (P = 0.034) between one SNP [GRK4 (A486V)] and the hypertensive patients was observed. Genotyping results for five of six SNPs were confirmed by digesting corresponding amplicons with locus-specific restriction endonucleases.

Conclusions: We developed a simple and homogeneous fluorescent protocol that has been used to determine the SNP genotype for six loci in a population of hypertensive and normotensive persons. We also observed a significant association (P = 0.034) between one SNP (A486V) and an Italian population of mildly hypertensive patients.

Descobrindo Genes no Século XXI: Enfoque na Área de Onco-Endocrinologia

A área de endocrinologia genética e oncológica tem sido alvo de enorme avanço nos anos recentes. A descoberta de genes responsáveis por neoplasias hereditárias nas últimas décadas representou uma fonte importante de informações concernentes à avaliação de risco, prevenção e aconselhamento genético. Neste particular, a caracterização do gene responsável pela neoplasia endócrina múltipla tipo 2 (MEN 2) representou a "pedra angular" para o desenvolvimento do campo de oncogenética clínica. Portanto, estima-se que o estudo genético e funcional das neoplasias hereditárias será igualmente capaz de liderar o avanço para um melhor manuseio clínico e terapêutico destas doenças. Um dos grandes desafios do futuro reside em se entender o intrincado mecanismo de interação entre genes e proteínas no controle do desenvolvimento e regulação dos diferentes sistemas biológicos. Uma das conseqüências mais antecipadas deste avanço é a sua aplicação para o tratamento específico e "individualizado" de todas as doenças humanas. Esta breve revisão tratará de aspectos gerais que envolvem o processo de identificação de novos genes e sua associação com condições clínicas específicas. As técnicas clássicas de clonagem serão apresentadas ao lado de estratégias modernas de identificação e análise de genes. O papel da bioinformática no Projeto Genoma Humano e o imenso potencial que esta informação traz para acelerar o processo de caracterização de novos grupos de genes serão brevemente discutidos.

Genomics versus orphan nuclear receptors--a half-time report

Following the successful cloning of the orphan nuclear receptors during the 1990s we entered the 21st century with knowledge of the full complement of human nuclear receptors. Many of these proteins are ligand-activated transcription factors that act as the cognate receptors for steroid, retinoid, and thyroid hormones. In addition to these well characterized endocrine hormone receptors, there are a large number of orphan receptors of which less is known about the nature and function of their ligands. The task of deciphering the physiological function of these orphan receptors has been aided by a new generation of genomic technologies. Through application of chemical, structural, and functional genomics, several orphan nuclear receptors have emerged as pharmaceutical drug targets for the treatment of important human diseases. The significant progress that has been made in the functional analysis of more than half of the nuclear receptor gene family provides an opportunity to review the impact of genomics in this endeavor.