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PubMed1996

Age-specific patterns of genetic variance in Drosophila melanogaster. II. Fecundity and its genetic covariance with age-specific mortality.

Under the mutation accumulation model of senescence, it was predicted that the additive genetic variance (VA) for fitness traits will increase with age. We measured age-specific mortality and fecundity from 65,134 Drosophila melanogaster and estimated genetic variance components, based on reciprocal crosses of extracted second chromosome lines. Elsewhere we report the results for mortality. Here, for fecundity, we report a bimodal pattern for VA with peaks at 3 days and at 17-31 days. Under the antagonistic pleiotropy model of senescence, it was predicted that negative correlations will exist between early and late life history traits. For fecundity itself we find positive genetic correlations among age classes > 3 days but negative nonsignificant correlations between fecundity at 3 days and at older age classes. For fecundity vs. age-specific mortality, we find positive fitness correlations (negative genetic correlations) among the traits at all ages > 3 days but a negative fitness correlation between fecundity at 3 days and mortality at the oldest ages (positive genetic correlations). For age-specific mortality itself we find overwhelmingly positive genetic correlations among all age classes. The data suggest that mutation accumulation may be a major source of standing genetic variance for senescence.

Aging↗

PubMed1986

Genetic change in milk yield estimated from simultaneous genetic evaluation of bulls and cows.

Genetic trend for milk yield in the artificially sired Holstein population in the northeastern United States was estimated from solutions for simultaneous genetic evaluations of bulls and cows for an animal model using mixed model equations and including all known relationships among the population by years of birth of 1960 to 1980 (1978 for bulls). First lactation milk records of 1,074,971 artificially sired cows sired by 6000 bulls in 20,065 herds were used. Averages of estimated genetic value by year of birth were similar from solutions after 10, 20, and 30 rounds of iteration of the mixed model equations. The trend in genetic value of bulls that entered artificial insemination was marked by slight negative change for three periods totaling 9 yr and substantial positive change averaging 105 kg/yr for the other 9 yr, which suggests that the dairy industry sacrificed milk yield in genetic value of bulls put into artificial insemination during those periods to selection criteria other than milk yield. There was little change in average genetic value of registered cows from 1960 to 1970. Gain in nonregistered cows totaled 177 kg for the same period. Gain from 1970 to 1980 was similar for both registered and nonregistered cows, 39.5 and 38.1 kg/yr, respectively. Average genetic value of nonregistered cows exceeded that of registered cows each year except 1960.

Animals↗

PubMed2004

Utility and limitations of genetic disease databases in clinical genetics research: a neurofibromatosis 1 database example.

Databases that collect clinical information on patients with particular genetic diseases can be used to investigate the clinical history of a disorder, its genetics, and genotype-phenotype correlations. A database can also serve as a valuable source of patients for studies of disease pathogenesis, variability, or treatment. We review the strengths and limitations of genetic disease databases in the context of our experience with the National Neurofibromatosis Foundation International Database (NNFFID). Genetic disease databases have been developed by individual investigators, scientific consortia, patient support organizations, and commercial enterprises. Databases vary from simple lists of affected individuals to comprehensive collections of detailed clinical and genetic information. Data may be obtained from people who volunteer to be included, systematic assessments of patients seen at participating medical centers, or population-based registries. Access to information may be highly restricted or widely available. These variables all affect the possible uses and usefulness of the data for research. Technical aspects of data entry, organization, storage, and retrieval, as well as issues related to data quality, confidentiality, and security, help determine how well a system actually functions. We discuss examples of research that have been accomplished with genetic disease databases and make recommendations regarding the organization and operation of these resources.

Biomedical Research↗

PubMed1982

Genetic analysis of human lymphocyte proteins by two-dimensional gel electrophoresis: 3. Frequent occurrence of genetic variants in some abundant polypeptides of PHA-stimulated peripheral blood lymphocytes.

The 100 or so most intensely Coomassie blue-stained polypeptides from PHA-stimulated peripheral blood lymphocytes were analyzed by two-dimensional electrophoresis in combination with family and population studies. Besides polymorphic lymphocyte cytosol 64k polypeptide reported previously, genetic variants were frequently observed in three polypeptides with molecular weights of 100,000, 49,000, and 40,000. All of them occur in the cytosol. These variant polypeptides are charge variants, because they are separated in the isoelectric focusing dimension. It is indicated by family and population studies and cell distribution analysis that the polypeptide with a molecular weight of 100,000 shows a genetic polymorphism determined by two alleles at a new autosomal locus, as described in the following paper. Family and population studies also suggest that a genetic polymorphism defined by alleles at an autosomal locus is present in each of the polypeptides with molecular weights of 49,000 and 40,000. In contrast to the previous reports of the extremely restricted genetic variability of the 100 or so most abundant fibroblast polypeptides, the present data indicate that common genetic variants are present at least in four of the 100 or so most intensely Coomassie blue-stained lymphocyte polypeptides. The result also shows that careful side-by-side comparison of two-dimensional electrophoresis patterns among both parents and their children is an effective method to detect genetic variant polypeptides.

Blood Protein Electrophoresis↗

PubMed1978

Variation in the genetic structure of Peromyscus populations. I. Genetic heterozygosity--its relationship to adaptive divergence.

The genetic structure of nine Peromyscus maniculatus nebrascensis demes from southeastern Wyoming was determined by analyzing allozymes encoded by 23 genetic loci with polyacrylamide gel electrophoresis. Genetic variability is extremely high for two genetic parameters; the proportion of loci polymorphic per deme averaged 0.41. Previous estimates of genetic heterozygosity for species within the genus Peromyscus have a mean of 0.06. The results of the present study suggest that genetic heterozygosity is considerably higher within P. maniculatus demes than within demes of other species in the genus. Geographic range is correlated with heterozygosity among Peromyscus species, as is adaptive divergence into broad-niched species. These correlates suggest that high heterozygosity may reflect an adaptation to a variable environment.

Adaptation, Physiological↗

PubMed1992

Genetic Tobit factor analysis: quantitative genetic modeling with censored data.

Parameters of quantitative genetic models have traditionally been estimated by either algebraic manipulation of familial correlations (or familial mean squares), biometric model fitting, or multiple-group covariance structure analysis. With few exceptions, researchers who have used these methods for the analysis of twin data have assumed that their data were multinormal and, consequently, have used normal-theory estimation methods. It is shown that normal-theory methods produce biased genetic and environmental parameter estimates when data are censored. Specifically, with censored data, (1) normal-theory estimates of narrow-sense heritability are either positively or negatively biased, whereas (2) estimates of shared-familial environmental variance are always biased downward. An alternative method for estimating genetic and environmental parameters from censored twin data is proposed. The method is called genetic Tobit factor analysis (GTFA) and is an extension of the Tobit factor analysis model developed by Muthén (Br. J. Math. Stat. Psychol. 42, 241-250, 1989). Using a Monte Carlo design, the performance of GTFA is compared to traditional quantitative genetic methods in both large and small data sets. The results of this study suggest that GTFA is the preferred method for the genetic modeling of censored data obtained from twins.

Genetics, Behavioral↗

PubMed2004

Genetic differentiation and trade among populations of peach palm ( Bactris gasipaes Kunth) in the Peruvian Amazon-implications for genetic resource management.

Peach palm ( Bactris gasipaes Kunth) is cultivated for fruit and 'heart of palm', and is an important component of agroforestry systems in the Peruvian Amazon. In this study, AFLP was used to compare genetic diversity among domesticated populations along the Paranapura and Cuiparillo rivers, which are managed by indigenous and colonist farming communities, respectively. Gene diversity was 0.2629 for the populations in indigenous communities and 0.2534 in colonist communities. Genetic differentiation among populations ( G(st)) was 0.0377-0.0416 ( P<0.01) among populations along both rivers. There was no relation between genetic differentiation and the geographical location of populations along the rivers. Since natural seed dispersal by birds and rodents is thought to occur only across relatively short distances (100-200 m), it is likely that exchange of material by farmers and commercial traders is responsible for most of the 'long-distance' (over more than 20 km) gene flow among populations along the two rivers studied. This exchange of material may be important to counteract the effects of selection as well as genetic drift in small groups of trees in farmers' fields, much as in a metapopulation, and may account for the weak genetic differentiation between the two rivers ( G(st)=0.0249, P<0.01). A comparison with samples from other landraces in Peru and Brazil showed the existence of an isolation-by-distance structure up to 3,000 km, consistent with gene flow on a regional scale, likely mediated by trade in the Amazon Basin. Results are discussed with regard to practical implications for the management of genetic resources with farming communities.

Agriculture↗

PubMed2005

Genetic evaluation and counseling of couples with recurrent miscarriage: recommendations of the National Society of Genetic Counselors.

The objective of this document is to provide recommendations for genetic evaluation and counseling of couples with recurrent miscarriage (RM). The recommendations are the opinions of the multidisciplinary Inherited Pregnancy Loss Working Group (IPLWG), with expertise in genetic counseling, medical genetics, maternal fetal medicine, internal medicine, infectious disease, cytogenetics, and coagulation disorders. The IPLWG defines RM as three or more clinically recognized consecutive or non-consecutive pregnancy losses occurring prior to fetal viability (<24 weeks gestation). These recommendations are provided to assist genetic counselors and other health care providers in clinical decision-making, as well as to promote consistency of patient care, guide the allocation of medical resources, and increase awareness of the psychosocial and cultural issues experienced by couples with RM. The IPLWG was convened with support from the March of Dimes Western Washington State Chapter and the University of Washington Division of Medical Genetics. The recommendations are U.S. Preventive Task Force Class III, and are based on clinical experiences, review of pertinent English-language published articles, and reports of expert committees. This document reviews the suspected causes of RM, provides indications for genetic evaluation and testing, addresses psychosocial and cultural considerations, and provides professional and patient resources. These recommendations should not be construed as dictating an exclusive course of medical management, nor does the use of such recommendations guarantee a particular outcome. The professional judgment of a health care provider, familiar with the circumstances of a specific case, should always supersede these recommendations.

Abortion, Habitual↗

PubMed2004

Genetics and genetic counseling: recommendations for Alzheimer's disease, frontotemporal dementia, and Creutzfeldt-Jakob disease.

In this paper we discuss the clinical genetics of three neurodegenerative diseases (Alzheimer's disease, frontotemporal dementia, and Creutzfeldt-Jakob disease), the current application of genetic testing for these diseases, and the role of genetic counseling in familial dementia. We review the literature addressing the clinical application of these genetic findings, including susceptibility testing and predictive testing. In addition, we share our own experience working with families with familial neurodegenerative disease, the genetic counseling process, and the major issues that need attention in the genetic counseling setting.

Aged↗

PubMed2003

The new genetics and its consequences for family, kinship, medicine and medical genetics.

In the past several decades there has been an explosion in our understanding of genetics. The new genetics is an integral part of contemporary biomedicine and promises great advances in alleviating disease, prolonging human life and leading us unto the medicine of the future. The aim of this paper is to explore the ways in which people make sense of the uncertainties that are associated with the new genetics, which by definition involve family and kinship relations. We explore the degree to which medical genetics places the patient in a double bind between the qualitative certainty and quantitative uncertainty of genetic inheritance that reinforce notions both of fear, and control of a person's future health. Second, we propose that the new genetics has medicalized family and kinship creating profound ethical and practical dilemmas for both the individual and for medicine as a whole.

Adult↗

PubMed2002

Models of genetic counseling and their effects on multicultural genetic counseling.

This theoretical paper examines challenges to multicultural genetic counseling, counseling between culturally different clients and counselors, in the context of Kessler's typology of models of genetic counseling (Kessler S (1997) J Genet Counsel 6:287-295). It is suggested that challenges such as resistance to multicultural genetic counseling education may be due to conceptions about genetic counseling as a biomedical field that transcends questions of culture as well as lack of multicultural training or prejudice. Directions for future research and recommendations for multicultural genetic counseling education are briefly explored.

Cultural Diversity↗

PubMed2006

A discrete choice experiment of preferences for genetic counselling among Jewish women seeking cancer genetics services.

To determine which aspects of breast cancer genetic counselling are important to Ashkenazi Jewish women, a discrete choice experiment was conducted. Participants consisted of 339 Australian Ashkenazi Jewish women who provided a blood sample for research used to test for Ashkenazi Jewish ancestral mutations in the genes BRCA1 and BRCA2, and were offered their genetic test result through a cancer genetics service. Main outcome measures were women's preferences for, and trade-offs between, the genetic counselling aspects of providing cancer, gene, and risk information (information); giving advice about cancer surveillance (surveillance); preparing for genetic testing (preparation); and, assistance with decision-making (direction). Respondents most valued information, about twice as much as advice about surveillance, four times as much as preparation for testing, and nine times as much as assistance with decision-making, which was least valued. Women's preferences were consistent with the major goals of genetic counselling, which include providing information and surveillance advice, and avoiding direction by facilitating autonomous decision-making. There were differences between the women in which aspects they most favoured, suggesting that counselling that elicits and responds to clients' preferences is more likely to meet clients' needs.

Adult↗

PubMed2003

Comparative genetic study confirms exceptionally low genetic variation in the ancient and endangered relictual conifer, Wollemia nobilis (Araucariaceae).

The Wollemi pine, Wollemia nobilis (Araucariaceae), was discovered in 1994 as the only extant member of the genus, previously known only from the fossil record. With fewer than 100 trees known from an inaccessible canyon in southeastern Australia, it is one of the most endangered tree species in the world. We conducted a comparative population genetic survey at allozyme, amplified fragment length polymorphism (AFLP) and simple sequence repeat (SSR) loci in W. nobilis, Araucaria cunninghamii and Agathis robusta - representatives of the two sister genera. No polymorphism was detected at 13 allozyme loci, more than 800 AFLP loci or the 20 SSR loci screened in W. nobilis. In Ag. robusta only one of 12 allozyme loci, five of 800 AFLP loci and none of the 15 SSR loci were variable. For A. cunninghamii, 10 of > 800 AFLP loci and five of 20 SSR loci were variable. Thus low genetic diversity characterizes all three species. While not ruling out the existence of genetic variation, we conclude that genetic diversity is exceptionally low in the Wollemi pine. To our knowledge this is the most extreme case known in plants. We conclude that the combination of small population effects, clonality and below-average genetic variation in the family are probable contributing factors to the low diversity. The exceptionally low genetic diversity of the Wollemi pine, combined with its known susceptibility to exotic fungal pathogens, reinforces current management policies of strict control of access to the pines and secrecy of the pine locations.

Australia↗

PubMed2003

Who should fund and control the direction of human behavior genetics? Review of Nuffield Council on Bioethics 2002 report, genetics and human behaviour: the ethical context.

In this (Nuffield Council on Bioethics 2002), the third in its series on ethics and related issues in genetics (see also Nuffield Council on Bioethics 1993 and Nuffield Council on Bioethics 1998), the Nuffield Council has focused on four'normal' behaviors; intelligence, personality, antisocial behavior and sexual orientation. This is a narrow range of behaviors and one where their discussion of the potential impact of predictive genetic testing is probably inappropriate. They also take an unduly narrow view of the purposes of behavior genetics in the 21st century. It is not simply to estimate heritability but to understand more about the structure of behavior and the processes which underlie it. Their narrow focus and their negative approach to the history and achievements of genetics is reflected in their less than positive support for future behavior genetic research. Behavior geneticists need to do more to publicize what their field has achieved in order to counter the very extensive antibehavior genetics initiatives which are almost unique in science. At the same time, organizations such as the Nuffield Council need to consider carefully the impact their deliberations may have on research funding.

Advisory Committees↗

PubMedDate not supplied

The social life of genetic knowledge: a case-study of choices and dilemmas in cancer genetic counselling in Denmark.

This article explores the social life of genetic knowledge in the context of cancer genetic counselling in Denmark. I focus on a specific case that occurred during my study of the processes through which genetic risk profiles are produced and through which knowledge of genes and kinship comes to appear both meaningful and contestable to counsellees. The analysis illuminates how participants in cancer genetic counselling experience gaps between, on the one hand, genetic information about kinship and predispositions to hereditary disease and, on the other hand, social experiences of kinship and risks. I argue that this gap constitutes a space for agency in which people make their own connections and interpretations. It is in this space that new social relations and understandings of bodies, health and kinship are crafted. Following the social life of genetic knowledge highlights how knowledge is practiced through social relations and how knowing is grounded in particular interactions and situated concerns.

Breast Neoplasms↗

PubMed2005

'Genetics is not the issue': insurers on genetics and life insurance.

This article offers an analysis of the way private insurers deal with the issue of genetics and insurance. Drawing on specific written insurance sources, a reconstruction is made of internal debates on genetics and insurance within the private insurance world in Europe and the United States. The article starts by analyzing the way insurers initially framed the issue of genetics. It proceeds by showing how ideas with respect to this issue developed beyond public policy debates in the nineties. Although not a strictly linear development, a trend towards a change in perspective can be demonstrated: at the beginning most insurance companies took another stance than they do nowadays. The article concludes by questioning the effect of these changes within the insurance world for the definition of the problem with respect to genetics and insurance. Does taking into account the public concerns around genetics also include taking genetics as a public problem?

Actuarial Analysis↗

PubMed1993

Genetic conditions among patients receiving genetic services in middle Tennessee.

We reviewed genetics charts of 2235 patients seen from 1985 to 1990 at Vanderbilt University Medical Center, Nashville, Tennessee, and summarized the 20 most common reasons for referral (occurring in 1138 of the patients) and the diagnoses or conditions among patients receiving genetic services in one of four clinical settings (prenatal counseling clinics, general genetics clinics, outreach genetics clinics, and ward consultations). The five most common reasons for referral were advanced maternal age (> or = 35 years) (203/1138, or 18% of patients), followed by dysmorphic features/multiple congenital anomalies (MCA) (185/1138; 16%), developmental delay/mental retardation (MR) (168/1138; 15%), Down's syndrome (103/1138; 9%), and abnormal maternal serum alpha-fetoprotein (MSAFP) (74/1138; 7%). The five most common diagnoses or conditions identified for all genetics patients were advanced maternal age (> or = 35 years) (195/906; 22%), developmental delay/MR (111/906; 12%), dysmorphic features/MCA (107/906; 12%), Down's syndrome (88/906; 10%), and multiple fetal losses (57/906; 6%). Of the 20 most common diagnoses or conditions categorized in 602 of the 906 patients, a multifactorial cause was observed in 25% of those patients; a chromosomal cause was observed in 26% of cases of Down's syndrome, accounting for 55% of the chromosomal disorders; a single gene disorder was observed in 17% of patients; an environmental cause was seen in 4%; and an unknown cause was noted in 28%. We hope this study will help physicians in middle Tennessee and surrounding areas by increasing their awareness of the types and frequencies of genetic diseases so that misdiagnoses and delayed referrals can be avoided.

Abnormalities, Multiple↗

PubMed1998

Foundations of genetics: genetic structure, function, and therapeutics.

Molecular genetics provides the basis for understanding patterns of health and disease in people and is part of the scientific foundation on which acute and critical care nurses should build their practice. The human genome, defined as all the genetic information in the cells of humans, provides the blueprint for protein production and cellular function in the body. Alterations in protein production may result in illness or organ malfunction that has a genetic derivation. One therapeutic strategy that holds promise to manage genetic diseases is gene therapy. Gene therapy, or human gene transfer, occurs when scientists or physicians modify the genetic material in cells for therapeutic purposes. Genetic structure, function, and therapeutic reflect the science of the present and future and have profound practice implications for acute and critical care nurses.

Genetic Diseases, Inborn↗