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Genetics of screwworm: new genetic markers and preliminary linkage map.

Eight new genetic markers for Cochliomyia hominivorax (Diptera: Calliphoridae), the screwworm, are characterized. The markers include three eye mutants, lemon-eye (le), cherry-eye (ch), and red-eye (re); one wing mutant, curly-wing (cw); and four allozyme markers, amylase (Amy-1), glycerol-3-phosphate dehydrogenase (Gpd), phosphoglucomutase (Pgm), and octanol dehydrogenase (Odh). The markers are associated into four linkage groups. Radiation-induced translocations were used to correlate the linkage groups with their respective chromosomes. A preliminary genetic linkage map with these and three previously characterized loci is presented.

Animals↗

[Medical genetics. Between consultation and molecular genetic research--an analysis of the current status].

Apparently, there is a much misunderstood discrepancy between the enormous successes achieved by genetic research and clinical applications, which so far have been relatively modest. Rapid progress in the identification of genetic components of diseases and the pathogenetic models derived from the information gained, signals both to the clinician and the patient that "genome analysis" is already available. The present article throws light on the situations in which gene analysis can be applied.

Adult↗

Genetic counseling: a comparison of counselee's genetic knowledge before and after (Part III).

Forty-seven mothers of children with Down syndrome were evaluated on their knowledge of genetic facts pertaining to Down syndrome. We found that more knowledge of this disorder was acquired by counselees before counseling than from counseling. The data show that counseling is most effective in enhancing counselees' knowledge of general genetics, ie, the origin of the extra chromosome in a child with Down syndrome. In contrast, counselees had the most difficulty in learning the recurrence risks for others, including the risks for relatives, siblings, and the population in general. A finding of practical importance is that formal education is inversely related to the amount of information counselees learned from counseling. Mothers with less than a high school education acquired most of their genetic knowledge from counseling, while those with more than a high school education acquired most of this information before counseling.

Down Syndrome↗

Psychological aspects of genetic counseling. II: Quantitative analysis of a transcript of a genetic counseling session.

The Bales system of scoring small group interactions was used to analyze a transcript of a preamniocentesis (genetic) counseling session in which a husband (H), wife (W), and a male counselor (C) participated. Scoring required the subdivision of communication into the smallest meaningful and scorable units, assigning each unit one of twelve possible category scores and designating the initiator and intended recipient(s) of the unit. The categories included "positive" and "negative" reactions, questions and attempted answers. Over half the units were found to consist of interactions in which information, orientation, and clarification were provided. C initiated 54% of all units of which three-quarters consisted of factual information regarding amniocentesis, genetic risks, Down syndrome, and mental retardation. C interacted significantly more frequently with W than with H, but units directed toward H were significantly more positive than those toward W. One interaction, in which C responded to affective material, significantly altered the subsequent frequency and direction of units; H became more verbal and there was an increase in further affective expression. Although evidence of persuasion was present, no directiveness was demonstrated. The data show that quantitative study of genetic counseling is feasible. Further research on different counseling styles and on the influence of specific interventions on later outcome has been undertaken.

Genetic Counseling↗

Famous people and genetic disorders: from monarchs to geniuses--a portrait of their genetic illnesses.

Famous people with genetic disorders have always been a subject of interest because such news feeds the curiosity the public has for celebrities. It gives further insight into their lives and provides a medical basis for any unexplained or idiosyncratic feature or behavior they exhibit. It draws admiration from society of those who excel in their specialized fields despite the impositions of their genetic illnesses and also elicits sympathy even in the most casual observer. Such news certainly catapults a rare genetic disorder into the realm of public awareness. We hereby present six famous figures: King George III, Toulouse-Lautrec, Queen Victoria, Nicolo Paganini, Abraham Lincoln, and Vincent van Gogh, all of whom made a huge indelible mark in either the history of politics or that of the arts.

Art↗

Description of the Genetic Analysis Workshop 11 Collaborative Study on the Genetics of Alcoholism.

Problem 1 of Genetic Analysis Workshop 11 consists of data from a family study of the genetics of alcoholism and related traits contributed by the six centers making up the National Institute for Alcohol Abuse and Alcoholism sponsored by the Collaborative Study on the Genetics of Alcoholism (COGA). The family data included 1,214 members of 105 pedigrees ascertained for having three or more individuals affected with alcoholism. Data available to workshop participants included clinical phenotypes, personality measures, smoking behavior, event-related potentials, platelet monamine oxidase B activity, and a genome scan of 296 markers.

Alcoholism↗

Genetic analysis of hepatitis A virus outbreak in France confirms the co-circulation of subgenotypes Ia, Ib and reveals a new genetic lineage.

Genetic analysis of selected genome regions of hepatitis A Virus (HAV) suggested that distinct genotype could be defined in different geographic locations. In order to study the degree of genetic variability among HAV isolated during a single epidemic outbreak, sequences from a 148 base pair segment within the VP1 amino terminal region were obtained for eight distinct HAV isolates from an outbreak that occurred in North Bretagne (France). These sequences were compared among themselves and with published sequences from 30 different strains that represented different HAV sub-genotypes that were isolated all over the world. Phylogenetic analysis revealed an extensive genetic heterogeneity among strains belonging to the same outbreak and revealed co-circulation of sub-genotype IA, IB, and the presence of IIIA sub-genotype for the first time in a Mediterranean country.

Adult↗

Some genetic implications of isoelectric focusing of human red cell phosphoglucomutase (PGM1) and serum protein group specific component (Gc): genetic diversity in the populations of Himachal Pradesh, India.

For the study of group specific component (Gc) and phosphoglucomutase (PGM1) polymorphism, isoelectric focusing was performed on eleven tribal and non-tribal populations of Himachal Pradesh, India. They were chosen to illustrate interregional and intraregional variations. The subtype frequencies of these two systems showed clear differences in the genetic constitution of these populations of Himachal at both levels. There is a large increase in the mean heterozygosity (H) for each system by isoelectric focusing over that shown by electrophoresis. Discriminant and distance analyses both suggest that the subtype frequencies provide greater potential for the study of genetic diversity among populations. The data on these additional alleles found by isoelectric focusing are examined for some of their genetic and anthropological implications.

Carrier Proteins↗

Genetic studies of the Macushi and Wapishana Indians. II. Data on 12 genetic polymorphisms of the red cell and serum proteins: gene flor between the tribes.

Blood samples from 509 Macushi (3 villages) and 623 Wapishana (11 villages) of Northern Brasil and Southern Guyana have been analyzed with respect to the phenotype and gene frequencies at the following 12 polymorphic loci: ABO, Kell-Cellano, MNSs, Rh, P, Duffy, Kidd, Diego, Lewis, Group-specific component, and the immunoglobulin allotypes of the Gm and Inv systems. The data suggest that 5-6% of the Wapishana gene pool is derived from non-Indians but only 1-2% of the Macushi. Inter- and intratribal genetic distances between villages are calculated for these data in an effort to understand gene flow between the tribes and to account for the unusual distribution of a newly-discovered genetic polymorphism of erythrocyte esterase A thus far limited to these 2 tribes (Neel et al., 1977). The data are puzzling and consistent with the possibility that both the Carib-speaking Macushi and the Arawak-speaking Wapishana have derived the esterase A allele in question from some third group now extinct or thus far undiscovered. Intertribal genetic distances based on gene frequencies at 6 loci are derived for 20 Amerindian tribes (including these 2); the "central" position of these 2 tribes can in part be explained by the active migration matrix connecting them.

ABO Blood-Group System↗

Identification of genetic markers to distinguish the virulent and avirulent subspecies of Pantoea stewartii by comparative proteomics and genetic analysis.

Pantoea stewartii subsp. stewartii (Pnss), the causal agent of Stewart's bacterial wilt and leaf blight of maize and sweet corn, is one of the quarantine pathogens in many countries and regions. In contrast, P. stewartii subsp. indologenes (Pnsi), the closely related subspecies of Pnss, is avirulent on these plants. In this study, the protein expression profiles of these two subspecies were compared using two-dimensional gel electrophoresis analysis. Twenty-one unique protein spots consistently detected in Pnss but not in Pnsi were analyzed by mass spectrometry. Some of these Pnss-specific proteins are known to be essential for virulence and survival in host, such as FoxR and HrcJ, which are the key components of iron uptake and Type III secretion systems, respectively. For further genetic analysis, six Pnss-specific proteins were characterized by peptide sequencing. Southern and Northern blot analyses revealed that the differences in protein expression profiles of the two subspecies were either due to the discrepancy at genome level or because of the variations in transcriptional expression. The results provide novel genetic markers to distinguish the two closely related subspecies and may also serve as useful clues for investigation of the genetic basis accounting for their sharp difference in virulence.

Amino Acid Sequence↗

Pathology and genetics of multiple system atrophy: an approach to determining genetic susceptibility spectrum.

Recent advances in the molecular pathology and genetics of multiple system atrophy (MSA) indicate that the disease involves plural pathogenic mechanisms. The determination of the morphological spectrum of MSA using quantitative pathological analysis points to the need for further investigation to determine the population-bound phenotype distribution of MSA. These notions support the hypothesis that a spectrum of genetic susceptibility factors underlies MSA pathogenesis. A possibly effective strategy for determining this genetic susceptibility spectrum is to perform an association study of important genes for neurodegenerative diseases, which are prevalent in a population, using linkage disequilibrium mapping in MSA patients with well-characterized morphological phenotypes.

Genetic Predisposition to Disease↗

Genetic analysis of a complex trait in the Utah Genetic Reference Project: a major locus for PTC taste ability on chromosome 7q and a secondary locus on chromosome 16p.

The ability to taste phenylthiocarbamide (PTC) shows complex inheritance in humans. We obtained a quantitative measure of PTC tasting ability in 267 members of 26 large three-generation families that were part of a set of CEPH families that had been used for genetic mapping. Significant bimodality was found for the distribution of age and gender adjusted scores (P<0.001), with estimated means of 3.16 (SD=1.80) and 9.26 (SD=1.54). Using the extensive genotyping available in these families from the genetic mapping efforts, we performed a genome scan by using 1324 markers with an average spacing of 4 cM. Analyses were first carried out with a recessive genetic model that has traditionally been assumed for the trait, and a threshold score of 8.0 delineating tasters from non-tasters. In this qualitative analysis, the maximum genome-wide lod score was 4.74 at 246 cM on chromosome 7; 17 families showed segregation of the dichotomous PTC phenotype. No other lod scores were significant; the next highest score was on chromosome 10 (lod=1.64 at 85 cM), followed by chromosome 3 (lod=1.29 at 267 cM). Because PTC taste ability exhibited substantial quantitative variation, the quantitative trait was also analyzed by using a variance components approach in SOLAR. The maximum quantitative genome-wide lod score was 8.85 at 246 cM on chromosome 7. Evidence for other possible quantitative loci was found on chromosomes 1 (lod=2.31 at 344 cM) and 16 (lod=2.01 at 14 cM). A subsequent two-locus whole-genome scan conditional on the chromosome 7 quantitative trait locus identified the chromosome 16 locus (two-locus lod=3.33 at 14 cM).

Adolescent↗

The genetics of obesity: from genetic epidemiology to molecular markers.

Obesity is a highly prevalent disease that carries enormous human and economic costs in western nations. The complexity and diversity of the paths leading to an overweight or an obesity status are enormous. The etiology, causes, associated morbidity, treatment, benefits versus risks of weight loss, prevention, and other aspects of obesity are all highly complex and intimately associated with other diseases, the prevalence of which is augmented by our present way of life. This article gives a brief overview of the current status of knowledge of the genetic basis of human obesity from a genetic epidemiology, experimental genetic and molecular biology perspective. It appears likely that the susceptibility to obesity depends, to a large extent, on several autosomal genes.

Agouti Signaling Protein↗

Genetic tumor archeology: microdissection and genetic heterogeneity in squamous and basal cell carcinoma.

Carcinogenesis is a multi-step series of somatic genetic events. The complexity of this multi-hit process makes it difficult to determine each single event and the definitive outcome of such events. To investigate the genetic alterations in cancer-related genes, sensitive and reliable detection methods are of major importance for generating relevant results. Another critical issue is the quality of starting material which largely affects the outcome of the analysis. Microdissection of cells defined under the microscope ensures a selection of representative material for subsequent genetic analysis. Skin cancer provides an advantageous model for studying the development of cancer. Detectable lesions occur early during tumor progression, facilitating molecular analysis of the cell populations from both preneoplastic and neoplastic lesions. Alterations of the p53 tumor suppressor gene are very common in non-melanoma skin cancer, and dysregulation of p53 pathways appear to be an early event in the tumor development. A high frequency of epidermal p53 clones has been detected in chronically sun-exposed skin. The abundance of clones containing p53 mutated keratinocytes adjacent to basal cell (BCC) and squamous cell carcinoma (SCC) suggests a role in human skin carcinogenesis. Studies using p53 mutations as a clonality marker have suggested a direct link between actinic keratosis, SCC in situ and invasive SCC. Microdissection-based studies have also shown that different parts of individual BCC tumors can share a common p53 mutation yet differ with respect to additional alterations within the p53 gene, consistent with subclonal development within tumors. Here, we present examples of using well-defined cell populations, including single cells, from complex tissue in combination with molecular tools to reveal features involved in skin carcinogenesis.

Basal Cell Carcinoma↗

Genetic characterization of Trypanosoma cruzi directly from tissues of patients with chronic Chagas disease: differential distribution of genetic types into diverse organs.

We have previously shown that a low-stringency single-specific primer-polymerase chain reaction (LSSP- PCR) is a highly sensitive and reproducible technique for the genetic profiling of Trypanosoma cruzi parasites directly in tissues from infected animals and humans. By applying LSSP-PCR to the study of the variable region of kinetoplast minicircle from T. cruzi, the intraspecific polymorphism of the kinetoplast-deoxyribonucleic acid (kDNA) sequence can be translated into individual kDNA signatures. In the present article, we report on our success using the LSSP-PCR technique in profiling the T. cruzi parasites present in the hearts of 13 patients with chagasic cardiopathy and in the esophagi of four patients (three of them with chagasic megaesophagus). In two patients, one with the cardiodigestive clinical form of Chagas disease and the other with cardiopathy and an esophageal inflammatory process, we could study both heart and esophagus and we detected distinct kDNA signatures in the two organs. This provides evidence of a differential tissue distribution of genetically diverse T. cruzi populations in chronic Chagas disease, suggesting that the genetic variability of the parasite is one of the determining factors of the clinical form of the disease.

Adult↗

Genetic and environmental influences on antisocial behaviors: evidence from behavioral-genetic research.

This article reviews behavioral-genetic research into human antisocial behavior. The focus is on studies of antisocial behavior that have been leading the way in investigating environmental and genetic influences on human behavior. The first generation of studies, which provided quantitative estimates attesting that genes and environments each influence about half of the population's variation in antisocial behaviors is interpreted. Then how behavioral-genetic methods are being applied to test developmental theory and to detect environmental causes of antisocial behavior is illustrated. Evidence for interactions between genes and the environment in the etiology of antisocial behavior is also examined. The article ends by envisioning future work on gene-environment interplay in the etiology of antisocial behavior.

Antisocial Personality Disorder↗

The status of genetic material and genetic information in The Netherlands.

The moral status of genetic material and information, and the ethics of controlling and manipulating them, is a topic of hot debate in many European countries, including The Netherlands. That heat is due partly to the complexity of the topic, and partly to researchers' fear that their investigations will be hampered by restrictions on the use of personal data or body material. But there is little doubt that manifold diverging interpretations about the status of the human body, body materials, and personal information in Dutch law, written and unwritten, contribute to the intensity of the debates. This article intends to structure the debate by creating more clarity at the conceptual level. By carefully examining relevant articles of the Constitution and Civil Codes, as well as policy documents and authoritative publications, notably in reference to prominent legal concepts such as property, ownership and privacy, and answer should be provided to the following crucial question: is the status of genetic material and information in any sense special in comparison with other body parts and other kinds of information about a person? This paper first discusses the status of human body materials and personal information in general, and then continues with a more specific discussion about the status of genetic material and information. It concludes that the Dutch legislature had carefully avoided (or not felt the need to employ) the concept of ownership in regulating biomedical research; rather, privacy is found to be the prime regulatory concept.

Confidentiality↗

Measuring the genetic influence in modulating the human life span: gene-environment interaction and the sex-specific genetic effect.

New approaches are needed to explore the different ways in which genes affect the human life span. One needs to assess the genetic effects themselves, as well as gene-environment interactions and sex dependency. In this paper, we present a new model that combines both genotypic and demographic information in the estimation of the genetic influence on life spans. Based on Cox's proportional hazard assumption, the model measures the risks for each gene as well as for gene-environment and gene-sex interactions, while controlling for confounding factors. A two-step MLE is introduced to obtain a non-parametric form of the baseline hazard function. The model is applied to genotypic data from Italian centenarian studies to estimate relative risks of candidate genes, risks due to interactions and initial frequencies of different genes in the population. Results from models that either do or do not take into consideration individual heterogeneity are compared. It is shown that ignoring the existence of heterogeneity can lead to a systematic underestimation of genetic effects and effects due to interactions.

Alleles↗