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PubMed1994

Genetic diversity of cultured Penaeus vannamei shrimp using three molecular genetic techniques.

Three molecular genetic techniques, restriction fragment length polymorphisms (RFLPs), random amplification of polymorphic DNA (RAPD), and allozyme variability, were used to evaluate the genetic diversity of two specific-pathogen-free (SPF) populations (numbers 1 and 2) and one candidate SPF population (number 4) of Penaeus vannamei developed and maintained by the U.S. Marine Shrimp Farming Program. A total of 114 individuals were tested, which included 30 each from families 1.5 and 1.6 of population 1 and from population 2, and 24 from population 4. Two HhaI mitochondrial DNA polymorphisms (A and B) were found in all the animals examined, with family 1.5 and population 2 showing type A and family 1.6 showing type B. After scoring 73 bands obtained with six different RAPD primers, the percentage of polymorphic bands was: 55% for families 1.5 and 1.6 of population 1, 48% for population 2, and 77% for population 4, suggesting that population 4 is the most polymorphic of all three populations. The allozymic variation at 30 loci showed no fixed differences in isozyme genotypes between families 1.5 and 1.6. The percentage of polymorphic loci, under the criterion that the frequency of the most common allele was less than 0.95 in each population, was 6.67%, 3.33% and 16.67% for family 1.5 of population 1, family 1.6 of population 1, and population 2, respectively. Mean heterozygosities (+/- SE) were 0.023 +/- 0.017, 0.018 +/- 0.016, and 0.064 +/- 0.026, respectively. The low levels of allozyme polymorphisms indicate that mitochondrial DNA and nuclear DNA techniques are more useful for examining genetic diversity in order to follow individual stocks within a breeding program and to correlate genotypes with desirable growth and reproductive performance of SPF P. vannamei stocks.

Animals↗
PubMed1995

Prenatal genetic counseling for hemoglobinopathy carriers: a comparison of primary providers of prenatal care and professional genetic counselors.

Health personnel trained in medical genetics are insufficient to meet the demand for genetic services. Methods must be found to enable primary care providers to offer commonly needed genetic services themselves. In our recently reported community-wide prenatal screening program for hemoglobinopathies, 36% of women detected to have a hemoglobinopathy did not come to a tertiary center for counseling and thus may have not benefited from testing. To determine whether the efficiency of the program could be increased if counseling were provided by the prenatal care provider (obstetrician or family practitioner), we developed a pilot training program on the basis of our experience in offering such services and enlisted 68% of regional prenatal care providers to participate. The proportion of patients detected to have a hemoglobinopathy who received counseling was similar in the primary and tertiary provider groups: 59% versus 50%, respectively, for sickle trait, and 69% versus 66%, respectively, for beta-thalassemia trait. Knowledge after counseling was also similar for the primary and tertiary provider groups: 64% versus 66% (mean % correct), respectively, for sickle trait, and 79% versus 78%, respectively, for beta-thalassemia trait. However, the two provider groups significantly differed with regard to whether or not the patient had her partner tested. For sickle trait, it was 25% for the primary providers but 49% for the tertiary providers (P < .001). For beta-thalassemia trait, it was 47% for the primary providers but 78% for the tertiary providers (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1997

[Does a genetic predisposition for infarction expansion exist? Evaluation of genetic polymorphisms of the renin-angiotensin system].

Aim of this study is to carry out a genetic analysis of polymorphisms of the renin-angiotensin system in a genetically homogeneous population, in patients with and without myocardial infarction (AMI) expansion and to evaluate the influence of non genetic, mechanical factors. The study was conducted on 299 patients with first AMI. Ecocardiography studies were performed on all patients on day 1 and 3 from the onset of AMI and before discharge. Eighty-four patients were excluded because of inadequate quality of echocardiograms and 215 (163 males, 52 females) were admitted. Of these, 157 had no evidence of AMI expansion (EXP-) while 58 had expansion (EXP+). DNA was extracted by standard methods from blood samples. Age and gender had no influence on AMI expansion. Anterior infarction (p < 0.000001) and Q-wave infarction (p < 0.00002) were found more frequently in EXP+. Peak of creatine phosphokinase was higher in EXP+ than in EXP- (p < 0.00001). The percent of patients treated with thrombolysis or with hypertension and/or left ventricular hypertrophy was not significantly different in the two groups. AGT MT235 polymorphism of angiotensinogen gene, I/D polymorphism of ACE gene and AT1 A1166C of AT1 receptor of angiotensin II were not significantly different in two groups. Stratified analysis showed that in patients with anterior AMI (n = 87), with a higher risk of AMI expansion, there is a significant difference (p < 0.02) in ACE genotype between EXP- and EXP+. Odds ratio assuming the dominant effect of I allele (II+ ID < DD) was 3.35 (confidence interval 1.41-7.56) with increased risk of expansion. More extension studies are need to verify if these results can contribute to early identification of patients at higher risk and to optimize therapeutic approach.

Aged↗
PubMed2002

Genetic counseling in hereditary breast/ovarian cancer in Israel: psychosocial impact and retention of genetic information.

Genetic counseling for individuals at high risk for developing breast and ovarian cancer (oncogenetic counseling) involves evaluation of cancer risk, psychological assessment, and genetic testing for germline mutations in BRCA1/BRCA2 genes. The long-term psychosocial impact of oncogenetic counseling on consultees and the retention of oncogenetic information are uncertain. We retrospectively interviewed 155 women who underwent oncogenetic counseling in a single medical center in Israel in 1996 (N = 50) and 1998 (N = 105). There were 29 (18.7%) BRCA1/BRCA2 mutation carriers and 126 non-carriers; 58 (37.4%) had a past or present history of cancer, and 97 (62.6%) were first-degree relatives within breast/ovarian cancer families. A questionnaire evaluating self-reported distress and anxiety symptoms before and after counseling, as well as the retention of relevant information (e.g., individual and offspring cancer risk, early detection schemes), one and three years after the initial consultation was administered. Overall, oncogenetic counseling had a minimal effect on anxiety-related symptoms. Mutation carriers reported anxiety-associated symptoms, such as sleeplessness and "bad mood", more frequently than non-carriers following oncogenetic counseling. As expected, 61.8% of carriers and only 30% of non-carriers accurately remembered the personal and offspring cancer risk and preventive and early detection schemes. We conclude that although there seemed to be slight worsening of anxiety-related symptoms following oncogenetic counseling in BRCA1/BRCA2 mutation carriers, these symptoms were minimal and did not affect everyday life activities. In addition, there is an ongoing need to emphasize oncogenetic information to high-risk individuals.

Adult↗
PubMed2006

When is a "positive" association truly a "positive" in psychiatric genetics? A commentary based on issues debated at the World Congress of Psychiatric Genetics, Boston, October 12-18, 2005.

The accumulated literature on candidate gene findings in psychiatric genetics is extensive. There is concern that many of the published findings to data are false positives. At the October 2005 World Congress of Psychiatric Genetics this issue was discussed by a panel of experts. This manuscript describes the panel discussion, its implications for the reporting of association studies of psychiatric disorders and suggestions for when to decide that a positive finding is truly positive.

Genetic Linkage↗
PubMed1974

Alpha-hydroxyacid oxidase genetics in the mouse: evidence for two genetic loci and a tetrameric subunit structure for the liver isozyme.

We have examined a polymorphism for liver GOX in inbred strains of the mouse Mus musculus. Genetic studies demonstrated that the two phenotypes for this enzyme present in BALB/C and NZC parental strains segregated as though they were controlled by codominant alleles at a single autosomal locus (GOX) which mapped closely to the agouti locus in linkage group V. Kidney HAOX activity is invariant in these inbred strains and is encoded by a separate genetic locus designated HAOX. BALB/C x NZC F(1) hybrid mice exhibited three intermediate forms of liver GOX activity, in addition to the parental enzymes, which is consistent with a tetrameric subunit structure.

Alcohol Oxidoreductases↗
PubMed1998

Evaluation of genetic variability and genetic distances between eight chicken lines using microsatellite markers.

The genetic variability and divergence of eight chicken lines were evaluated using nine microsatellite markers. The chicken lines included three White Leghorn hybrids, three Finnish Landrace lines, a Rhode Island Red line, and a broiler hybrid line. All the microsatellite loci were found to be polymorphic, the number of alleles varying from 4 to 13 per locus and 1 to 10 per line, respectively. Observed heterozygosities ranged from 0.00 to 0.91. The highest (0.67) and lowest (0.29) mean heterozygosity per line was observed in the broiler and in White Leghorn of Mäkelä, respectively. Three of the microsatellite loci deviated from the Hardy-Weinberg equilibrium in some populations. F statistics indicated clearly the subdivision of the total population into different lines. The genetic distances confirmed the classification of Finnish Landraces into different lines. A phylogenetic consensus tree was constructed from resampled data (1,000 times) using the neighbor-joining method. According to the phylogenetic tree, the lines were grouped into three clusters, in which the White Leghorns formed one group, two Landraces a second group, and a Landrace, the Rhode Island Red, and the broiler lines a third group. Allele distribution at the loci does not support either the stepwise or the infinite alleles mutation model, but the distribution pattern was quite irregular at different loci.

Animals↗
PubMed1999

Genetic markers to predict polygenic disease: a new problem for social genetics.

Many genetic markers that relate to common multifactorial disease in adults have been identified during the past 15 years. Their use as adjuncts for the diagnosis, prognosis, prediction of disease or targeting therapy for these disorders has begun, good examples being the Factor V Leiden mutation for venous-thromboembolism, lipoprotein lipase mutations for hypertriglyceridaemia and the apolipoprotein E4 variant for Alzheimer's dementia. However, extensive gene-gene and gene-environment interactions make their use more complex than markers for the simpler monogenic disorders (such as cystic fibrosis, or Duchenne's muscular dystrophy). Possible misapplication of the genetic markers for multifactorial disease in the fields of risk prediction, direct sales to the public, life assurance, employment rights, and legislation for regulation of their use are discussed.

Adult↗
PubMed2006

Community genetics and dignity in diversity in the Quebec Network of Genetic Medicine.

The Quebec Network of Genetic Medicine (QNGM), implemented in 1971, has been an integrated program of community genetics serving the population (approximately 7.5 million) of Quebec province in Canada. QNGM reported to the Minister of Social Affairs and operated under an umbrella of universal health insurance in the province. The Network's programs have been run by members of the four university medical schools of the province under the direction of a central committee. A global annual budget was awarded to QNGM from its inception. Among its many programs, QNGM supported: (1) two newborn screening programs (using blood and urine samples) for early diagnosis, treatment and research in phenylketonuria, hereditary tyrosinemia, congenital hypothyroidism, and in a large number of other hereditary metabolic diseases; (2) follow-up of confirmatory diagnostic tests at regional centers, followed by supervision of ambulatory treatment modalities; (3) carrier screening and reproductive counseling for Tay-Sachs and beta-thalassemia diseases; (4) a spectrum of feasibility (research) studies (e.g., screening for biotinidase deficiency, neuroblastoma, hemoglobinopathies, and cystic fibrosis) to inform policy decisions. QNGM performed economic analyses of its major programs and followed prevailing ethical guidelines. Its global budget and integrated structure terminated in 1994, although some of its programs continue independently.

Cystic Fibrosis↗
PubMed2000

"What do you think about genetic medicine?" Facilitating sociable public discourse on developments in the new genetics.

An important aspect of any meaningful public discussion about developments in gene technology is the provision of opportunities for interested publics to engage in sociable public discourse with other lay people and with experts. This article reports on a series of peer group conversations conducted in late 1996 and early 1997 with sixteen community groups in Perth, Western Australia, interested in gene therapy technology. With the case of cystic fibrosis as a particular focus, and using background resource material as a stimulus for discussion, the participating groups explored a range of value issues arising from the new genetic medicine. This more discursive context enabled participants to express a number of background or life-world concerns about genetic medicine, concerns that are often obscured by the dominant biomedical and bioethical discourses.

Attitude↗
PubMed2004

Genetics and genetic testing: are GPs likely to attend training courses?

BACKGROUND: GPs must make difficult screening and diagnostic decisions regarding genetic testing for different cancers. Educational programs may improve knowledge and enable more appropriate referral. METHODS: A postal survey of all general practitioners (GPs) in Northern Ireland (N = 534; response rate = 49.4%) asked GPs if they would attend 3 different types of training courses in genetics. RESULTS: Almost 75% indicated that they would be likely and/or very likely to attend such courses. Women and GPs who had been qualified recently were most likely to attend (P < .005, P < .05). CONCLUSION: The results suggest that GPs are interested in training courses. Male GPs and GPs who have been qualified for longer should be specifically targeted.

Data Collection↗
PubMed2005

Genetic bases of estrogen-induced pituitary tumorigenesis: identification of genetic loci determining estrogen-induced pituitary growth in reciprocal crosses between the ACI and Copenhagen rat strains.

Estrogens stimulate proliferation and enhance survival of the prolactin (PRL)-producing lactotroph of the anterior pituitary gland and induce development of PRL-producing pituitary tumors in certain inbred rat strains but not others. The goal of this study was to elucidate the genetic bases of estrogen-induced pituitary tumorigenesis in reciprocal intercrosses between the genetically related ACI and Copenhagen (COP) rat strains. Following 12 weeks of treatment with the synthetic estrogen diethylstilbestrol (DES), pituitary mass, an accurate surrogate marker of absolute lactotroph number, was increased 10.6-fold in ACI rats and 4.5-fold in COP rats. Composite interval mapping analyses of the phenotypically defined F(2) progeny from the reciprocal crosses identified six quantitative trait loci (QTL) that determine the pituitary growth response to DES. These loci reside on chromosome 6 [Estrogen-induced pituitary tumor (Ept)1], chromosome 3 (Ept2 and Ept6), chromosome 10 (Ept9), and chromosome 1 (Ept10 and Ept13). Together, these six Ept loci and one additional suggestive locus on chromosome 4 account for an estimated 40% of the phenotypic variance exhibited by the combined F(2) population, while 34% of the phenotypic variance was estimated to result from environmental factors. These data indicate that DES-induced pituitary mass behaves as a quantitative trait and provide information that will facilitate identification of genes that determine the tumorigenic response of the pituitary gland to estrogens.

Animals↗
PubMed2000

Molecular genetic testing in pediatric practice: A subject review. Committee on Genetics.

Although many types of diagnostic and carrier testing for genetic disorders have been available for decades, the use of molecular methods is a relatively recent phenomenon. Such testing has expanded the range of disorders that can be diagnosed and has enhanced the ability of clinicians to provide accurate prognostic information and institute appropriate health supervision measures. However, the proper application of these tests may be difficult because of their scientific complexity and the potential for negative, sometimes unexpected, consequences for many patients. The purposes of this subject review are to provide background information on molecular genetic tests, to describe specific testing modalities, and to discuss some of the benefits and risks specific to the pediatric population. It is likely that pediatricians will use these testing methods increasingly for their patients and will need to evaluate critically their diagnostic and prognostic implications.

Adolescent↗
PubMed1984

Molecular genetics, recombinant DNA techniques, and genetic neurological disease.

The molecular defects responsible for Huntington's disease, the spinocerebellar degenerations, myotonic muscular dystrophy, neurofibromatosis, and tuberous sclerosis, among other major dominant inherited diseases of the nervous system, will be identified using the new techniques of molecular genetics. With synthesized nucleic acid segments complementary to portions of the patient's DNA, known as complementary DNA probes, it will be possible to identify and isolate the mutant gene responsible for a particular disease. These events are referred to as gene cloning. In addition, complex genetic regulatory mechanisms involved in cell differentiation during neuroembryogenesis will be elucidated with the application of these strategies. It is important for the clinician to become familiar with the precision and potential of these new methodologies, because they will soon influence significantly the practice of neurology.

Chromosome Mapping↗
PubMed2004

Multiple hybrid origins, genetic diversity and population genetic structure of two endemic Sorbus taxa on the Isle of Arran, Scotland.

Understanding the processes that have given rise to polyploid hybrid taxa is central to our understanding of plant evolution. In this study, we use an array of genetic markers in a population analysis to elucidate the hybrid origins of the Arran whitebeams Sorbus arranensis and S. pseudofennica, two woody plant taxa endemic to the Isle of Arran, Scotland. It has been proposed that S. arranensis was derived by hybridization between S. aucuparia and S. rupicola, and that subsequent hybridization between S. arranensis and S. aucuparia gave rise to S. pseudofennica. Analyses of species-specific isozyme, nuclear intron and chloroplast DNA markers confirm the proposed origin of S. arranensis, and indicate that S. aucuparia was the female parent in the hybridization. Analysis of microsatellite markers suggests that there have been at least three origins of S. arranensis on Arran. Microsatellite markers also support the proposed hypothesis for the origin of S. pseudofennica, and indicate at least five hybrid origins of this taxon. In total, three multilocus genotypes of S. arranensis and eight of S. pseudofennica were detected on Arran and multilocus genotypic diversity levels Hg were 0.09 and 0.63, respectively. Genetic differentiation (thetaST) values based on multilocus genotypes are substantial (0.344 and 0.470 for S. arranensis and S. pseudofennica, respectively) implying limited seed flow among populations. These results indicate that the endemic Sorbus taxa on Arran are the products of multiple and ongoing evolutionary events. This information must be incorporated into management policies for their future conservation.

Conservation of Natural Resources↗
PubMed2004

Genetic variation in cancer predisposition: mutational decay of a robust genetic control network.

A computational model of cancer progression is used to study how mutations in genes that control tumor initiation and progression accumulate in populations. The model assumes that cancer occurs only after a cell lineage has progressed through a series of stages. The greater the number of stages, the more strongly the individual is protected against cancer. It is shown that an extra stage initially improves the survival of individuals by decreasing mortality from cancer. However, the additional buffering by an extra stage reduces the impact of any single hereditary mutation and therefore allows the accumulation of more nonlethal mutations in the population. Extra stages thereby lead to the evolution of partially decreased cancer mortality and significantly increased genetic predisposition to disease in the population as a whole. In general, the model illustrates how all robust control networks allow the accumulation of deleterious mutations. An increase in the number of buffering components leads to significant mutational decay in the protection provided by each buffering component and increased genetic predisposition to disease. An extra buffering component's net contribution to survival and reproduction is often small.

Aging↗
PubMed1981

Estimating genetic divergence and genetic variability with restriction endonucleases.

Restriction endonucleases cut DNA at specific sites determined by the local nucleotide sequence. By comparing related DNA segments with respect to where such cuts are made, one can estimate the extent of sequence homology between the segments. Empirical methods are presented here for using these data to measure the proportion of mismatches between two sequences, the proportion of polymorphic positions in a series of sequences, or the degree of heterozygosity in a population. These methods do not require any assumptions concerning the evolutionary or population genetic processes involved. One can also use the data to calculate the precision of each of these estimates. When the positions of the cuts are not determined, these estimates can be made, using only the lengths of the resulting DNA fragments, by means of a maximum likelihood procedure. Several examples demonstrate the usefulness of these methods to study genetic differences in regions of the genome not amenable to study by other methods.

DNA↗