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PubMed1989

Univariate genetic analysis of blood pressure in children (the Medical College of Virginia Twin Study).

The relative contributions of genetic, individual environmental and shared environmental effects on resting blood pressure (BP) and heart rate (HR) were studied in prepubescent twins. The study population consisted of 251 caucasian 11-year-old twin pairs. Correlations were higher for all variables in monozygotic twins compared to dizygotic twins; this is consistent with a significant genetic effect. Path analysis revealed that the model of additive genetic and individual environmental effects fit systolic BP, diastolic BP and HR. In boys and girls, sex-specific genetic effects controlled systolic BP. The magnitudes of the sex-specific genetic effects on systolic BP were similar in both boys and girls and accounted for 66% of the variance. In boys, for diastolic BP, genetic effects accounted for 64% of the variance while in girls they accounted for 51%. These results provide no evidence for different genetic effects on HR in boys or girls. No shared environmental effects were detected. The large sample size and design, using different-sex dizygotic twins of the same age, establish that genes play an important role in the influence of resting BP and HR and that there are sex-specific genetic contributions in early pubertal children.

Blood Pressure↗
PubMedDate not supplied

Genetic analysis of Giardia from hoofed farm animals reveals artiodactyl-specific and potentially zoonotic genotypes.

Thirty one Giardia isolates, established from six species of hoofed livestock by axenic culture or growth in suckling mice, were compared genetically by analysis of DNA amplified from loci encoding variant surface proteins or the enzyme glutamate dehydrogenase and by allozyme analysis. The isolates were heterogeneous, but all showed affinity with genetic Assemblage A--one of two major assemblages defined previously by analysis of Giardia from humans. Three distinct genotypes were evident. Ten isolates (eight axenic and two established in suckling mice) from an alpaca, pig, horse, cattle and sheep were indistinguishable from human-derived G. intestinalis belonging to a previously designated genetic group (Group I). This genotype seems to have broad host specificity, including a zoonotic potential for humans. Five isolates (two axenic and three established in suckling mice) from an alpaca, a horse and sheep had close affinity with human-derived Group I and Group II G. intestinalis genotypes. The other 16 isolates (comprising both axenic and suckling mouse-propagated cultures derived from cattle, sheep, alpaca, a goat and pigs in Australia and Europe) differed from all other Giardia with "duodenalis" morphology that have been examined by these methods and they segregated as a highly distinct sublineage (referred to herein as 'Novel livestock') within genetic Assemblage A. The predominance of 'Novel livestock' genotypes in the test panel and their apparent exclusive association with artiodactyl hosts indicates that they may be confined to this group of mammals. Assemblage B genotypes, which are prevalent in humans and some other animal species, were not detected.

Animals↗
PubMed2005

Genetic analysis of the antibody response to AAV2 and factor IX.

We have analyzed the antibody response against either AAV2 or canine F.IX (cF.IX) in parental C57BL/6 (B6) and DBA/2 (D2) and 18 strains of B6 x D2 (BXD) recombinant inbred (RI) strains of mice after iv administration of AAV2-(ApoE)4/hAAT-cF.IX. There was a higher anti-AAV2 capsid response in B6 compared to D2 mice, with IgG2b being the major isotype separating the high and low responders in these two strains. In contrast, the antibody response to cF.IX was lower than the response to the AAV2 capsid and was limited to the IgG1 isotype in both strains. Genetic linkage analysis of the IgG2b anti-AAV2 antibody response in BXD RI strains revealed a significant locus at D4Mit164 (29 cM, LRS=15.3) and two suggestive loci at D6Mit16 (30.5 cM, LRS=11.2) and D17Mit187 (47.4 cM, LRS=13.1). Genetic linkage analysis of the IgG1 anti-cF.IX antibody response revealed a suggestive locus at D1Mit218 (67 cM, LRS=14.1). Significant epistatic interaction was found between two loci (D8Mit45 and D16Mit47; LOD=6.54) for anti-AAV2 and two other loci (D5Mit348 and D15Mit161; LOD=7.66) for anti-cF.IX. These results indicate that multiple genetic loci independently regulate the isotype-specific antibody response to the AAV2 capsid and the cF.IX transgene.

Alleles↗
PubMed1979

Multivariate behavioral genetic analysis of twin data on scholastic abilities.

Multivariate behavioral genetic analyses may employ either genetic and environmental correlations or phenotypically standardized covariances to assess the structure of genetic and environmental influences. Correlations and phenotypically standardized covariances answer different questions--correlations are appropriate for understanding the nature of genetic and environmental influences, whereas covariances are appropriate for determining the etiology of phenotypic correlations. The ratio of the genetic and environmental covariances to the phenotypic correlation yields estimates of bivariate heritability and environmentality, measures of the extent to which observed phenotypic covariance is due to genetic and environmental influences. Multivariate analyses of genetic and environmental correlations and covariances are illustrated with twin data on scholastic abilities. Factor analyses of correlations suggest that the same set of genes affects the major areas of academic achievement and that the environmental influences are similarly structured. Analyses of phenotypically standardized covariances indicate that the structures of genetic and environmental influences as they contribute to phenotypic resemblance among scholastic abilities are both similar and simple: there are one general genetic factor and one general environmental factor. Bivariate heritabilities and environmentalities are similar in magnitude, indicating that the strong phenotypic relationship among scholastic abilities is due roughly equally o genetic and environmental influences.

Analysis of Variance↗
PubMed2002

Genetic analysis of lithium-associated parathyroid tumors.

OBJECTIVE: The aim of this study was to determine the primary genetic events that may underlie the formation of parathyroid tumors in patients with lithium-associated hyperparathyroidism (HPT). METHODS: Comparative genomic hybridization (CGH), loss of heterozygosity (LOH) and multiple endocrine neoplasia type 1 gene (MEN1) mutation analysis were used to analyze twelve parathyroid tumors from nine patients with lithium-associated HPT. For comparison, CGH was also carried out in a non-lithium-associated group of thirteen sporadic parathyroid tumors. RESULTS: A higher prevalence of multiglandular disease in the lithium-associated HPT patients compared with the idiopathic sporadic patients was observed (Fisher's exact test, P=0.02). CGH alterations were detected in four lithium-associated parathyroid tumors, involving loss at 1p, 11, 15q, 22q and gain of the X chromosome. In addition, one of these four cases exhibited LOH at 11q13 and was found to contain a novel somatic MEN1 mutation (c.1193insTAC). Although fewer lithium-associated parathyroid tumors were shown to contain genetic alterations compared with the sporadic parathyroid tumors, the changes detected were those frequently associated with both familial and sporadic parathyroid tumorigenesis. CONCLUSION: This is, to our knowledge, the first genetic analysis of parathyroid tumors in lithium-associated HPT patients. Our data indicated that the majority of lithium-associated parathyroid tumors do not contain gross chromosomal alterations and suggest that in most cases the tumorigenic pathway is independent of MEN1 and genes at 1p34.3-pter and 1q21-q32. It is possible that other discrete genetic alterations or epigenetic changes, not screened for in this study, could also be responsible for parathyroid tumorigenesis in lithium-associated HPT.

Adolescent↗
PubMed1971

Genetic analysis of lysine auxotrophs of Staphylococcus aureus.

The genetics of lysine biosynthesis in Staphylococcus aureus was examined by a transductional analysis of lysine auxotrophs. These mutants had previously been grouped according to their biochemical characteristics. The mutant sites appeared to be closely linked. Complementation was observed between different groups but not between mutant strains belonging to the same group. A strain was detected which seemed to have a mutant control region. Evidence is presented to support the hypothesis that the lysine biosynthetic region functions as an operon.

Chromosome Mapping↗
PubMed1990

Genetic analysis of an inherited predisposition to colon cancer in a family with a variable number of adenomatous polyps.

We studied a large kindred with a history of colorectal cancer of early onset. Proctosigmoidoscopic examination of 51 family members identified only 2 with familial polyposis coli, which strongly predisposes those who have it to colorectal cancer and which is defined as the presence of more than 100 polyps in the colon. However, eight family members had 2 to 40 colonic polyps. We suspected that in this family, colorectal cancer was the result of a mutation in the gene on chromosome 5 that is responsible for familial polyposis coli. To test our hypothesis, we obtained genotypic information on 81 family members with respect to seven polymorphic DNA markers previously shown to be linked to the locus for familial polyposis coli. Multilocus analysis of the data demonstrated genetic linkage (lod score, 5.58) between these markers and the locus responsible for the defined syndrome of colonic polyps or colorectal cancer in this kindred. These findings constitute evidence that the genetic defect in this family is a mutation in the gene that causes familial polyposis coli. We conclude that mutations at the genetic locus for familial polyposis coli may be the cause of other, more subtle syndromes involving an inherited susceptibility to colonic adenomatous polyps and colorectal cancer.

Adenomatous Polyposis Coli↗
PubMed2003

[Origin of Hakka and Hakkanese: a genetics analysis].

Hakka is a distinctive Han Chinese population in Southern China speaking Hakkanese. The origin of Hakka has been controversial. In this report, we analyzed Y chromosomal markers in 148 Hakka males. Principle component analysis of Y-SNP haplotype distribution shows Hakka is clusteed strongly with the Han in Northern China, and is also close to She, a Hmong-Mien-speaking population, while the general Southern Han is fairly close to Daic populations. Admixture analysis revealed that the relative genetic contribution 80.2% (Han), 13% (She) and 6.8% (Kam) in Hakka. The network of Y-STR haplotype of M7 individuals in all concerned populations suggested two possible origins of Hmong-Mien contribution in Hakka: One is from Hubei and the other is from Canton. The Kam contribution in Hakka is likely from Kan-Yue, the ancient aborigine of Kiangsi (Jiangxi). The frequency of 9bp-deletion in Region V of mitochondrial DNA of Hakka is 19.7%, which is quite close to She but far from Han. We therefore concluded that genetically the majority of Hakka gene pool shall come from North Han with She contributing the most among all non-Han groups. Regarding the Hmong-Mien character of Hakkanese, the genetic structure of Hakka shows their core may be Kim-man, the ancient Hmong-Mien. We hypothesized that a great number of Han people from North China join this population in succession. Southern Chinese dialects, such as Hakkanese may also be those languages of Southern aborigines at first, and turn to extant appearance under the continuance effect of Northern Chinese.

China↗
PubMed1997

Clinical and genetic analysis of an inherited case of thyroid adenoma/cancer.

We studied a family in which thyroid neoplasms appeared to occur through genetic inheritance. Six blood relations, including the two probands, had thyroid carcinoma, and six others had benign thyroid tumors. When both parents had a thyroid neoplasm, their children frequently had thyroid neoplasms; this was confirmed through two generations of this family. To clarify the mechanism of inheritance, we performed chromosomal analysis, Southern blot analysis of three variable number of tandem repeats markers and HLA typing on two probands, and examined their RET proto-oncogenes, and p53 and RB tumor suppressor genes. We could not find any positive data on genetic analysis, although our data were limited. In conclusion, we studied a family in which thyroid neoplasms have occurred partly through genetic inheritance, although environmental factors may have influenced the occurrence of thyroid diseases. A search for a predisposing gene, using the microsatellite technique, is required to clarify the gentic factors involved.

Adenoma↗
PubMed2005

Multivariate genetic analysis of academic skills of the Queensland core skills test and IQ highlight the importance of genetic g.

This study examined the genetic and environmental relationships among 5 academic achievement skills of a standardized test of academic achievement, the Queensland Core Skills Test (QCST; Queensland Studies Authority, 2003a). QCST participants included 182 monozygotic pairs and 208 dizygotic pairs (mean 17 years +/- 0.4 standard deviation). IQ data were included in the analysis to correct for ascertainment bias. A genetic general factor explained virtually all genetic variance in the component academic skills scores, and accounted for 32% to 73% of their phenotypic variances. It also explained 56% and 42% of variation in Verbal IQ and Performance IQ respectively, suggesting that this factor is genetic g. Modest specific genetic effects were evident for achievement in mathematical problem solving and written expression. A single common factor adequately explained common environmental effects, which were also modest, and possibly due to assortative mating. The results suggest that general academic ability, derived from genetic influences and to a lesser extent common environmental influences, is the primary source of variation in component skills of the QCST.

Adolescent↗
PubMed1999

Genetic analysis of susceptibility to infection with Ascaris lumbricoides.

Epidemiologic studies of helminthic infections have shown that susceptibility to these parasites frequently aggregates in families, suggesting the possible involvement of genetic factors. This paper presents a genetic epidemiologic analysis of Ascaris lumbricoides infection in the Jirel population of eastern Nepal. A total of 1,261 individuals belonging to a single pedigree were assessed for intensity of Ascaris infection at two time points. Following an initial assessment in which all individuals were treated with albendazole, a follow-up examination was performed one year later to evaluate reinfection patterns. Three measures of worm burden were analyzed, including eggs per gram of feces, direct worm counts, and worm biomass (weight). For all traits, variance component analysis of the familial data provided unequivocal evidence for a strong genetic component accounting for between 30% and 50% of the variation in worm burden. Shared environmental (i.e., common household) effects account for between 3% and 13% of the total phenotypic variance.

Adolescent↗
PubMed2005

Molecular epidemiology of infectious bursal disease viruses: distribution and genetic analysis of newly emerging viruses in the United States.

Genetic mutations in the genome of infectious bursal disease virus (IBDV) have resulted in antigenic and pathogenic variants that continue to cause disease in commercially reared chickens. The extent of the genetic diversity among IBDV strains circulating in the United States is unknown. This study was designed to identify newly emerging viruses infecting chickens on poultry farms experiencing immune suppression-related problems. Fifty IBDV-positive samples were identified from 273 bursa samples using a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. Mutation probes were designed to the hydrophilic B coding region of the VP2 gene. Six mutation probes used in this study were based on the nucleotide sequences of the Del-E, Bursine 2, D-78, STC, G6, and T1 IBDV strains. Following real-time RT-PCR, these mutation probes identified 11 of the 50 viruses in the melting temperature (Tm) analysis. The results indicated that the remaining 39 viruses had one or more nucleotide mutations compared with the six mutation probes in this region of the VP2 gene. Thirty-eight viruses were chosen for nucleotide sequence analysis across the hypervariable region of the VP2 gene. Within this group of 38 viruses, four were identified by the mutation probes and their nucleotide sequences confirmed that real-time RT-PCR data. In the remaining 34 viruses, nucleotide mutations were observed in as many as 8 of 23 nucleotides across the hydrophilic B epitope coding region. Furthermore, every amino acid position except one between 316 and 324 had at least one substitution mutation. Phylogenic analysis placed two of the 38 viruses sequenced on branches with classic viruses and the remaining 36 viruses were placed on four distinct branches. Branches 1 and 2 contained a majority of the viruses, which were distributed across most of the major poultry-producing states in the United States. These branches contained previously characterized variant IBDV strains. Viruses in branches 3 and 4 were confined to three states and did not contain any previously characterized IBDV strains.

Animals↗
PubMed2003

Application of laser capture microdissection in genetic analysis of neuroblastoma and neuroblastoma precursor cells.

Recently developed quantitative and high-throughput technologies that allow automated and rapid screening of the whole genome, transcriptome and proteome have revolutionized the field of cancer genetics. At the same time, new challenges are met, e.g. the need for improved data analysis and standardization of tumor sample handling. Even if these issues are resolved, an 'old' problem in genetic tumor analysis remains, i.e. contamination of tumor samples by stromal and surrounding normal cells. To overcome this obstacle, laser capture microdissection (LCM) has been developed in order to procure the cells of interest from stained tissue sections with retention of morphology. In this review we describe the possible down-stream applications of LCM in the genetic analysis of neuroblastoma (NB). Special focus is given to MYCN copy number determination using real-time quantitative polymerase chain reaction (Q-PCR), analysis of 1p-, 3p- and 11q-deletions using loss of heterozygosity analysis and Q-PCR expression analysis of microdissected normal neuroblast cells and NB cells.

DNA, Neoplasm↗
PubMed1999

Gene mapping by linkage and association analysis.

Genetic analysis is used to map genes, including disease loci, to positions within the human genome. Linkage analysis depends on the co-segregation of a gene (locus) and a phenotype through a pedigree, while association analysis, or linkage disequilibrium mapping, depends on measuring deviation from the random occurrence of alleles in a haplotype in unrelated individuals or nuclear families. Complex computer programs may be used in both forms of analysis. In recent years most interest has focused on identifying genes involved in common, multifactorial diseases. Here I review some current and developing techniques of genetic analysis and give references to where further information can be obtained.

Animals↗
PubMed2001

Genetic analysis in the asexual fungus Aspergillus niger.

The genetics of A. niger has been developed since 1980. An overview is presented of the advances in developing methods and collecting data. Important tools have been a) the application of essentially different methods to isolate mutants, b) the adaptation to A. niger ofA. nidulans methodology for analysis of the parasexual cycle, c) the choice of marker genes, and in some cases the artificial introduction of such genes, to select homozygous segregants arising from mitotic recombination. With the use of parasexual recombination, a genetic linkage map of A. niger has been established. In total, 110 nuclear and 1 cytoplasmic (mitochondrial) markers are available. The application of A. niger genetics in applied research is illustrated by examples.

Aspergillus niger↗
PubMed1995

Molecular genetic analysis of the ripening-inhibitor and non-ripening loci of tomato: a first step in genetic map-based cloning of fruit ripening genes.

Ripening represents a complex developmental process unique to plants. We are using tomato fruit ripening mutants as tools to understand the regulatory components that control and coordinate the physiological and biochemical changes which collectively confer the ripe phenotype. We have genetically characterized two loci which result in significant inhibition of the ripening process in tomato, ripening-inhibitor (rin), and non-ripening (nor), as a first step toward isolating genes likely to encode key regulators of this developmental process. A combination of pooled-sample mapping as well as classical restriction fragment length polymorphism (RFLP) analysis has permitted the construction of high-density genetic maps for the regions of chromosomes 5 and 10 spanning the rin and nor loci, respectively. To assess the feasibility of initiating a chromosome walk, physical mapping of high molecular weight genomic DNA has been employed to estimate the relationship between physical distance (in kb) and genetic distance (in cM) around the targeted loci. Based on this analysis, the relationship in the region spanning the rin locus is estimated to be 200-300 kb/cM, while the nor locus region ratio is approximately 200 kb/1 cM. Using RFLP markers tightly linked to rin and nor, chromosome walks have been initiated to both loci in a yeast artificial chromosome (YAC) library of tomato genomic DNA. We have isolated and characterized several YAC clones linked to each of the targeted ripening loci and present genetic evidence that at least one YAC clone contains the nor locus.

Base Sequence↗
PubMed1985

Relationships among three Muslim and one Hindu endogamous groups of Madhya Pradesh. I. Genetic distance analysis.

Genetic distances have been estimated among three Muslim groups, the Sunni, Shia and the Bohra, and a Hindu group, the Brahman, from five districts of the centrally located state of Madhya Pradesh in India. The distances are based on five genetic systems, the ABO, MN and Rh blood groups. PIC taste sensitivity and colour blindness. None of the 6 distances among the 4 groups was statistically significant. However, cluster analysis showed that Sunni and Shia form a very close cluster which is successively joined by Brahman and Bohra, the latter having comparatively large distances from all the other groups.

Alleles↗