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PubMed2005

Genetic basis and risk factors for infectious and noninfectious diseases in US Holsteins. I. Estimation of genetic parameters for single diseases and general health.

Health data collected from 1996 to 1999 from 177 herds in Minnesota and Wisconsin were analyzed to establish genetic basis for infectious and noninfectious diseases. Three types of health traits were targeted. First, available infectious conditions were used to identify animals that are superior in their general immunity (including innate immunity) for infectious diseases. Generalized immunity may be thought of as a combination of immune responses to a variety of immune system challenges. Second, single infectious and noninfectious diseases were analyzed separately. Third, infectious reproductive diseases as one category of related conditions, and cystic ovary disease as one category of 3 related noninfectious ovary disorders were studied. Data were analyzed using a threshold model that included herd, calving year, season of calving, and parity as cross-classified fixed factors; and sire and cow within sires as random effects. Days at risk and days in milk at the beginning of a record were included by fitting the days as continuous covariates in the model. A heritability value of 0.202 +/- 0.083 was estimated for generalized immunity. Heritability values of 0.141 and 0.161 were estimated for uterine infection and mastitis, respectively. Heritability of single noninfectious disorders ranged from 0.087 to 0.349. The amount of additive genetic variance recovered in the underlying scale of noninfectious disorders tended to zero when combining multiple conditions. The study supports combining infectious diseases into categories of interest but we do not recommend the same approach for noninfectious disorders.

Abomasum↗
PubMed2005

Genetic analyses of mastitis data using animal threshold models and genetic correlation with production traits.

In the present study, 6 different mastitis data sets of 3 dairy herds with an overall herd size of 3200 German Holstein cows were analyzed. Data collection periods included the first 50, 100, or 300 d of lactation. The 3 data collection periods were analyzed with a lactation model and a test-day model. All models were animal threshold models. Mastitis frequencies in the lactation model data sets varied between 29 and 45%, and varied between 3 and 6% in the test-day model data sets. Depending on the period of data collection, heritabilities of liability to mastitis in the lactation models were 0.05 (50 d), 0.06 (100 d), and 0.07 (300 d). In the test-day models, heritabilities were slightly higher with values of 0.09 (50 and 100 d), and 0.06 (300 d). Between lactation models, the rank correlations between the relative breeding values were high and varied between 0.86 and 0.94. Rank correlations between the relative breeding values of the test-day models ranged from 0.68 to 0.87. The rank correlations between the relative breeding values of lactation models and test-day models varied from 0.51 and 0.80. Genetic correlations between mastitis and milk production traits were estimated with a linear animal test-day model. The correlations with mastitis were 0.29 (milk yield), 0.30 (fat yield), 0.20 (fat content), 0.34 (protein yield), and 0.20 (protein content). The estimated genetic correlation between mastitis and somatic cell score was 0.84.

Animals↗
PubMed1992

Genetics and resistance to tuberculosis. Could resistance be enhanced by genetic engineering?

Recent observations strongly suggest a significant role for genetic factors in innate resistance to infection by Mycobacterium tuberculosis. This relation was discovered in a study of tuberculosis in Arkansas nursing homes and was supported by data from three outbreaks of tuberculosis in two prisons. A person's resistance level was found to correlate with the region of his or her ancestry. Ancestors of person's in the more resistant group tended to derive from densely populated areas and cities rife with tuberculosis, whereas the ancestors of person's in the more susceptible group tended to derive from areas once free of tuberculosis. In accordance with current genetic theory, those persons who are less resistant to tuberculosis would be expected to be more resistant to infections endemic to the region once inhabited by their ancestors. Isolation of the gene previously shown to confer specific innate (nonimmune) resistance to tuberculosis should result in the creation of a more rational approach to increasing the capacity of human macrophages to kill tubercle bacilli without producing a positive tuberculin skin test.

Black People↗
PubMed1999

[Geography of genetic processes in the population: genetic migration in Northern Eurasia (Central Asia region)].

Based on the data of the census of 1970, a map of the rates of gene migrations in the rural population of Central Asia and Kazakhstan was drawn. The corrected average value for 35 populations of oblasts (administrative regions) and autonomous republics was m = 0.0606 +/- 0.0102. The estimate obtained from the mapped data was 0.0799 +/- 0.0014, which is 1.2-fold higher than similar values for Europe. The relationship between the rate of gene migration m, the genetically effective population size Ne, and the density of elementary populations in the studied area Pp was analyzed by means of correlation and regression analyses. The following relationship was obtained: m = A/Ne + BPp, where A > 0 and B < 0. This was accounted for by the fact that the migration flow is mainly directed to the less densely populated rural areas. Given that the region was chosen somewhat artificially, studying gene migrations in Central Asia and Kazakhstan as separate historical, geographic, and genetic subregions of northern Eurasia might be a better approach.

Asia↗
PubMed2000

[The significance of genetic and environmental factors for migraine with aura. A genetic epidemiologic study of Danish twins].

We studied the genetic and environmental influence on migraine with aura (MA) by analysing a twin population. The twin sample consisted of 2,026 monozygotic (MZ) pairs and 3,334 same-gender dizygotic (DZ) pairs recruited from the population-based Danish Twin Register. A total of 211 pairs were identified, of whom 77 were MZ and 134 were DZ. The pairwise concordance rate was significantly higher in MZ-than in DZ-pairs, i.e. 34% and 12%, respectively, emphasizing the importance of genetic factors in MA. However, environmental factors are also important, as the pair wise concordance rate was less than 100% in MZ-pairs. Similarly, the recurrence risk of MA was 50% in MZ- and 21% in DZ-pairs which was a significant difference. In non-twin siblings, the recurrence risk of MA is 27%, which is similar to the recurrence risk in DZ-pairs. This indicates that MA is not developed due to specific environmental factors shared by the twins.

Adult↗
PubMed2000

Lynch syndrome: genetics, natural history, genetic counseling, and prevention.

Lynch syndrome is the most common hereditary form of colorectal cancer (CRC). Its natural history has been investigated extensively, so that highly targeted surveillance and management strategies, melded to its natural history, have proven effective in cancer control. Most important is the early age of onset of cancer (approximately 44 years), involving CRC and the several extracolonic cancers that are integral to the syndrome. With respect to CRC, approximately 70% of cases occur proximal to the splenic flexure. Synchronous and metachronous CRCs are extremely common. Full colonoscopy should be initiated when the patient is between the ages of 20 and 25, and because of the accelerated carcinogenesis of CRC, it should be performed every 1 to 2 years. The presence of initial CRC requires subtotal colectomy, given the mentioned increased frequency of metachronous cancer. Options available for germ-line mutation carriers, in addition to cancer screening, include prophylactic colectomy as well as prophylactic total abdominal hysterectomy and bilateral salpingo-oophorectomy. The discovery of mismatch repair germ-line mutations (most commonly MSH2 or MLH1) has added significantly to the recognition of this disease as well as to the search for high-risk individuals throughout families who, with genetic counseling, may become candidates for germ-line mutation testing. Clearly, hereditary nonpolyposis colorectal cancer provides an excellent opportunity for learning about the etio-pathogenesis of cancer at the molecular and clinical levels and how this knowledge might ultimately be exploited for cancer control. A search for chemoprevention agents, such as cyclo-oxygenase 2 inhibitors, as well as for putative environmental effects and how they may interact with the genetic component in CRC etiology should abet this entire cancer control process.

Awards and Prizes↗
PubMed2000

Characteristics of myotonic dystrophy in Istria: molecular genetic approach. Part II: Analysis of genetic polymorphisms.

One of the world highest prevalence estimates of myotonic dystrophy (DM) has been reported in the Croatian region Istria. To analyse the population genetic characteristics of DM locus in Istria, two intragenic and three extragenic polymorphic markers were tested. The Southern blot technique was used for D19S63 locus analysis, whereas PCR analysis was performed for CKMM, Alu polymorphism, DMPK (G/T) intron 9/HinfI polymorphism, and D19S207 genetic markers. The compound haplotypes segregating with DM were established. A complete association between the DM mutation and D19S63, D19S207, intron 9/HinfI polymorphism and Alu polymorphism markers were found. In all DM chromosomes: D19S63 and Alu markers had the allele 1 in common; D19S207 had the allele 3 in common, DMPK (G/T) intron 9/HinfI marker had the allele 2 in common. The analysis of CKMM polymorphism revealed genotype heterogeneity; in DM chromosomes either allele 2 or allele 4 were found. The haplotype analysis in the population of Croatian Istria supports the linkage disequilibrium between the DM mutation and Alu polymorphism, intron 9/HinfI polymorphism, D19S63 and D19S207 markers as reported worldwide. The results of the haplotype analysis suggest a common origin of the mutation in Istrian population.

Adult↗
PubMed2006

[Population genetic study of Russian cosmonauts and test subjects: genetic demographic parameters and immunogenetic markers].

Genetic demographic characteristics and immunogenetic markers (blood groups ABO, Rhesus, MNSs, P, Duffy, Kidd, and Kell) have been studied in a group of 132 Russian cosmonauts and test subjects (CTSG). Analysis of pedigrees has shown a high exogamy in the preceding generations: almost half of the subjects have mixed ethnic background. According to the results of genetic demographic analysis, a sample from the Moscow population was used as control group (CG). Comparison between the CTSG and CG has demonstrated significant differences in genotype frequencies for several blood group systems. The CTSG is characterized by a decreased proportion of rare interlocus genotypic combinations and an increased man heterozygosity. Analysis of the distributions of individual heterozygosity for loci with codominant expression of alleles has shown that highly heterozygous loci are more frequent in the CTSG. Taking into account that the CTSG has been thoroughly selected from the general population, it is concluded that heterozygosity is related to successful adaptation to a space flight.

Adaptation, Physiological↗
PubMed1991

Genetic studies of human apolipoproteins. XX. Genetic polymorphism of apolipoprotein J and its impact on quantitative lipid traits in normolipidemic subjects.

Apolipoprotein J (apo J) is a newly identified member of a growing family of proteins associated with various lipoprotein particles. Apo J is a glycoprotein which exists in the plasma associated with high-density lipoprotein subfractions which also contain apo A-I and cholesteryl ester transfer protein (CETP). We have investigated the possible existence of genetic polymorphism at the apo J structural locus and have evaluated its role in lipid metabolism. By employing isoelectric focusing and immunoblotting techniques, we have screened plasma or serum samples from six population groups: U.S. whites, Amerindians, Eskimos, New Guineans, U.S. blacks, and Nigerian blacks. Apo J revealed a common two-allele polymorphism only in populations with African ancestry and was found to be monomorphic in all other population groups tested. The genetic basis of the two alleles designated--APO J*1 and APO J*2, at a single structural locus, apo J-- was confirmed in a large number of segregating families. In the U.S. blacks, the frequencies of the APO J*1 and APO J*2 alleles were .76 and .24, respectively, and in the Nigerian blacks these values were .72 and .28, respectively. In addition, a single example of a rare allele designated APO J*3 was also encountered in the U.S. black sample. In Nigerian blacks, the apo J polymorphism's impact on seven quantitative lipid traits--total cholesterol, LDL-cholesterol, HDL-cholesterol, HDL3-cholesterol, HDL2-cholesterol, VLDL-cholesterol, and triglycerides--was investigated. No significant impact of the apo J polymorphism was observed for any of these lipid traits.

Adolescent↗
PubMed1991

[Uncovering the features of population genetic structures by the descriptive method of "genetic landscape"].

It was found that using surnames as genetical markers in rural Russian populations gives adequate results under conditions of working on the area not extending over the territory of 2 or 3 adjacent regions. Schematic drawings of genetic landscapes in 4 regions of the Kirov district and in 2 regions of the Adyg district are presented. Analysis of anomalous features of equidistant lines has been performed.

Genetics, Population↗
PubMed1990

Genetic heterogeneity of plasma lipoproteins in the mouse: control of low density lipoprotein particle sizes by genetic factors.

In order to assess the genetic control of sizes and concentrations of mouse plasma low density (LDL) and high density lipoproteins (HDL), we used gel permeation fast protein liquid chromatography (FPLC) and nondenaturing gradient polyacrylamide gel electrophoresis to measure the particle sizes of LDL and HDL. Using chromatography we also quantified LDL-cholesterol and HDL-cholesterol concentrations in plasma and used them as indexes of plasma concentrations of the respective particles among 10 inbred strains (AKR/J, BALB/cByJ, C3H/HeJ, C57BL/6J, C57BL/6ByJ, C57L/J, DBA/1LacJ, 129/J, NZB/BINJ, SWR/J) and three sets of recombinant inbred (RI) strains (AKXL/TyJ, BXH/TyJ, CXB/ByJ) of mice. HDL had a dichotomous distribution among the 10 inbred strains. One group had large HDL particle sizes and high HDL-cholesterol concentrations. Another group had smaller HDL particles and lower HDL-cholesterol concentrations, and HDL sizes and HDL-cholesterol concentrations were significantly correlated. In the RI strains, HDL sizes and HDL-cholesterol cholesterol concentrations clearly segregated with one or another of the progenitor strains, and RI strain distributions showed a strong linkage to the apolipoprotein (apo) A-II gene (Apoa-2). In contrast, LDL-cholesterol concentrations and particle sizes on FPLC did not show dichotomous distributions among the 10 inbred strains. In RI strains, the configuration of the LDL FPLC profiles and LDL-cholesterol concentrations did resemble one or another of the progenitors in the majority of cases, but LDLs of several RI strains resembled neither progenitor strain in profile configuration, and LDL-cholesterol concentrations were both greater and smaller than those of progenitor strains. However, LDL particle diameters (as judged by peaks of LDL-cholesterol profiles) did segregate with progenitors in 29/33 (88%) of RI strains suggesting that a major gene may affect LDL size. In attempting to identify a major LDL-size determining gene, we compared apoB gene restriction fragment length polymorphisms (RFLPs) to the distributions of peak LDL sizes in RI strains. Concordance rates of peak LDL sizes to apoB gene polymorphisms were 18/22 (82%) for the EcoRV RFLP, 5/7 (71%) for HindIII RFLP, and 23/29 (79%) for both (range of P values 0.90-0.95). Thus we could not unequivocally implicate the apoB gene in determining the size of LDL particles. In summary, the genetic control of LDL sizes is more complicated than is the case for HDL; however, the differences in LDL size among these strains of mice may be controlled by a major, as yet unidentified, gene.

Animals↗
PubMed1989

Innovations in human genetics education. Alternative methods of instruction in medical genetics.

A course in medical genetics for first-year medical students was developed with the use of alternative methods of instruction, including audiovisual materials and computer-assisted instruction. The use of this methodology enabled students to consider many significant areas of medical genetics, without a dependency on the traditional lecture-based instructional format. Seventy-eight percent of the students identified the alternative instructional methods as an enhancement to their education. These students performed a mean of 6% better on class examinations.

Curriculum↗
PubMed1987

Estimation of additive genetic, non-additive genetic, and permanent environmental sources of variation in preweaning traits in swine using the expectation-maximization algorithm for restricted maximum likelihood.

10188 growth records (performance up to weaning) of 283 Largewhite pigs were used to estimate various components of variance using a mixed linear model for the birth weight, litter size at birth, weaning weight, and litter size at weaning. Restricted maximum likelihood procedures were used. Object of the investigation were the respective additive genetic, non-additive genetic, and permanent environmental variation traits within the overall variation as well as the respective residual components. The results were tabulated and expressed specifically by way of the heritability and repeatability coefficients.

Animals↗
PubMed1986

[Genetic and ecological study of aboriginal populations of northeastern Siberia. I. Gm-haplotypes and their frequency in 10 chukchi populations. Genetic structure of reindeer chukchi].

G1m (z, a, x, f) and G3m (g, b0, b1, b3, b5, s, t) allotypes were tested in 1079 Chukchi inhabitants of interior Chukotka and adjacent Kamchatka. Genetic variation at this particular locus is provided by the presence of three haplotypes, namely, za;g, zax;g and za;bO35st, revealed with mean frequencies of 0.748, 0.089 and 0.154, respectively. Traces of Caucasian Gm (f;bO135) haplotype were observed in 9 of 10 populations studied. Judging from its frequency in the whole group (0.009), European admixture in Reindeer Chukchi did not exceed 1.3%. Analysis of covariance and variance matrices containing gene frequencies for 11 polymorphic loci revealed the aspects of genetic structure. Simultaneously, the action of systematic versus nonsystematic pressure was also evaluated and interpreted in the light of historical and ecological events.

Asian People↗
PubMed1983

[Genetic research in the field of reproductive pathology and genetic prophylaxis in agricultural animals in the Socialist Republic of Romania].

The paper presents the results of some genetic studies accomplished in Romania in the field of pathology of reproduction in domestic animals (pseudohermaphroditism in horses, testicular hypoplasia in he-goats, intersexuality in pigs, freemartinism and genital infantilism in cattle). Also, the use of the cytogenetic test in genetic prophylaxis in pigs and cattle was shown. In addition, the methods for detecting genitors with undesirable genes were devised and perspectives for the development of hereditary hygiene discussed.

Animal Diseases↗
PubMed1980

Alpha-locus hexosaminidase genetic compound with juvenile gangliosidosis phenotype: clinical, genetic, and biochemical studies.

A 3-year-old boy developed progressive neurological deterioration in his third year, characterized by dementia, ataxia, myoclonic jerks, and bilateral macular cherry-red spots. Hexosaminidase A (HEX A) was partially decreased in the patient's serum, leukocytes, and cultured skin fibroblasts. Hexosaminidase was studied in serum and leukocytes from family members. Four members of the paternal branch appeared to be carriers of classical infantile Tay-Sachs allele, HEX alpha 2, probably receiving the gene from one great-grandparent of Ashkenazi origin. In the maternal branch, no one was a carrier of classical infantile Tay-Sachs disease, but five individuals were carriers of a milder alpha-locus defect. The patient, therefore, was a genetic compound of two different alpha-locus hexosaminidase mutations. At least 21 families with late-infantile or juvenile GM2 gangliosidosis have been reported, 18 of them with alpha-locus mutations, and three with beta-locus mutations. Genetic compounds of hexosaminidase have been reported in at least seven families, five with alpha-locus mutations and two with beta-locus mutations. The compound had the phenotype of infantile Tay-Sachs disease in one family, infantile Sandhoff disease in another, and the normal phenotype in the rest.

Child, Preschool↗
PubMed1978

[Genetics and genetic counselling in childhood epilepsy (author's transl)].

According to electroencephalographical studies on the pathogenesis of epilepsy a hereditary predisposition plays a greater role than believed before. It is far more frequent than the manifest disease. The phenomenon of cerebral excitability is influenced by different genetically determined, differently age- and sexdependent but amongst each other independent factors. When defining the risk of epilepsy for siblings and descendents in practice, one is forced to proceed from the statistical empirical value with all its uncertainty. During the past few years, the figures have become more exact for special types of epilepsy as absence-epilepsy, myoclonic astatic Petit mal, and Impulsiv-Petit mal. Details of these results and their consequences for genetic advice are discussed.

Adolescent↗
PubMed1982

[Genetic problems of stress. V. The genetics of adrenal cortical reactivity in emotional stress in rats].

Genetic analysis of adrenocortical reactivity (the level of plasma corticosterone and secretion of the adrenal gland in vitro) was carried out under conditions of emotional stress in three inbred strains of rats (Wistar, August, Sprague-Dawley) and in their F1 reciprocal hybrids. The basal adrenocortical function was similar in genotypes studied. However, significant genotype-dependent variability was demonstrated under conditions of stress stimulation. The variability of adrenal secretion in vitro was mediated by genes displaying an additive action, while variability in the level of plasma corticosterone included components both of general combining ability and of specific combining ability. Also, the role of a reciprocal effect was noted. The peculiarities of genetic determination of adrenocortical reactivity to emotional stress are discussed.

11-Hydroxycorticosteroids↗