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Results for “genotype frequency”

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At least 109 records · Page 6Linked to original sources
PubMed1995

PCR analysis of the short tandem repeat (STR) system HUMVWA31. Allele and genotype frequencies in an Italian population sample.

A population study in a sample of 211 unrelated individuals from 2 cities in North and Central Italy was carried out to investigate the short tandem repeat (STR) system HUMVWA31. Separation of PCR- amplified DNA fragments was performed by high-resolution horizontal denaturing polyacrylamide gel electrophoresis (PAGE) followed by silver staining. The 7 common alleles were found, together with a new smaller allele. Distribution of the observed genotypes did not deviate from Hardy-Weinberg (H-W) equilibrium. The power of discrimination for this locus was 0.93 and the chance of exclusion was 0.61. Good agreement was found between the allele frequencies in 2 Italian population samples and previous studies on Caucasians. The results of this study suggest that this STR system may be a useful tool in forensic investigations.

Alleles↗
PubMed2000

Allele and genotype frequencies for D1S80 and 3'APOB in Recanati, Central Italy.

The VNTR 3'APOB and D1S80 loci were studied in a sample of 179 individuals living in the Recanati Area (Central Italy). For 3'APOB, we found 34 genotypes and 11 alleles. The system was in Hardy-Weinberg equilibrium. The observed and expected heterozygosity were 0.788 and 0.798 respectively. The discrimination power was 0.96, the a-priori paternity exclusion power was 0.619 and the polymorphism information content was 0.773. For D1S80, we found 45 genotypes and 18 alleles. The system deviated significantly from Hardy-Weinberg equilibrium. The observed and expected heterozygosity were 0.696 and 0.790 respectively. The discrimination power was 0.96, the a-priori paternity exclusion power was 0.617 and PIC was 0.767. The Recanati sample was compared with the general Italian frequencies for the 3'APOB locus. A difference of borderline significance was detected (P = 0.04). For D1S80, the sample was compared with a sample from Southern Italy and no significant difference was detected.

Alleles↗
PubMed2001

PrP genotype frequencies in German breeding sheep and the potential to breed for resistance to scrapie.

Genetic susceptibility to scrapie is associated with polymorphisms in three different codons of the ovine prion protein (PrP) gene (136, 154, 171). Studies of PrP genotypes linked to scrapie have revealed the resistance of homozygous PrPARR/PrPARR animals and the high risk of PrPVRQ/PrPVRQ and PrPvRQ/PrPARQ animals in scrapie-affected flocks. The selection of PrPARR/PrPARR genotypes may therefore provide a strategy for controlling clinical scrapie. The genotypes of 1361 German breeding sheep from 15 different breeds in northern Germany were determined. Apart from the wildtype allele PrPARQ, at least four mutually exclusive allelic variants were found. The greatest variability within the PrP gene was encountered in texel sheep, in which 14 PrP genotypes were found. In the important meat breeds, Suffolk, German whiteheaded mutton and German blackheaded mutton, the PrPARR allele was predominant, and in these breeds the breeding of scrapie-resistant pedigree flocks within four generations seems to be a feasible option. In the texel sheep, the German merino, the German milk and the German land sheep breeds, the frequency of the PrPARR allele was much lower, and in several breeds no homozygous rams were available for breeding purposes. In these breeds the breeding strategy would depend on the number of heterozygous rams available, but resistant pedigree flocks could be achieved within nine generations.

Animal Husbandry↗
PubMed2005

Early-onset parkinsonism associated with PINK1 mutations: frequency, genotypes, and phenotypes.

OBJECTIVE: To assess the prevalence, nature, and associated phenotypes of PINK1 gene mutations in a large series of patients with early-onset (<50 years) parkinsonism. METHODS: The authors studied 134 patients (116 sporadic and 18 familial; 77% Italian) and 90 Italian controls. The whole PINK1 coding region was sequenced from genomic DNA; cDNA was analyzed in selected cases. RESULTS: Homozygous pathogenic mutations were identified in 4 of 90 Italian sporadic cases, including the novel Gln456Stop mutation; single heterozygous truncating or missense mutations were found in another 4 Italian sporadic cases, including two novel mutations, Pro196Leu and Gln456Stop. Pathogenic mutations were not identified in the familial cases. Novel (Gln115Leu) and known polymorphisms were identified with similar frequency in cases and controls. In cases carrying single heterozygous mutation, cDNA analysis detected no additional mutations, and revealed a major pathogenic effect at mRNA level for the mutant C1366T/Gln456Stop allele. All patients with homozygous mutations had very early disease onset, slow progression, and excellent response to l-dopa, including, in some, symmetric onset, dystonia at onset, and sleep benefit, resembling parkin-related disease. Phenotype in patients with single heterozygous mutation was similar, but onset was later. CONCLUSIONS: PINK1 homozygous mutations are a relevant cause of disease among Italian sporadic patients with early-onset parkinsonism. The role of mutations found in single heterozygous state is difficult to interpret. Our study suggests that, at least in some patients, these mutations are disease causing, in combination with additional, still unknown factors.

Adolescent↗
PubMed2001

Genotype Frequencies of Cyclooxygenease 2 (COX2) Rare Polymorphisms for Japanese with and without Colorectal Cancer.

Cyclooxygenase 2 (COX2) is an inducible enzyme synthesizing prostaglandins from arachidonic acid, which is thought to play an important role in colorectal carcinogenesis. Since the COX2 polymorphisms, if functional, may modify the carcinogenesis pathway, the associations between the reported polymorphisms and colorectal cancer risk were examined in a hospital-based case-control study. Six polymorphisms of the gene encoding COX2 were genotyped for 241 non-cancer individuals (controls) and 148 colorectal cancer patients (74 colon cancer, 73 rectal cancer, and 1 colorectal cancer date, 22 polymorphisms including the above six have been reported for COX2. The other polymorphisms remain to be examined.

Journal Article↗
PubMed1987

Genotype frequency differences in Halipegus occidualis-infected and uninfected Helisoma anceps.

Allozyme frequencies in Helisoma anceps infected with the hemiurid trematode, Halipegus occidualis, were compared with those of uninfected H. anceps from a small, North Carolina farm pond. Of 6 loci found to be polymorphic, the frequencies of esterase-1 and leucine aminopeptidase were different in infected and uninfected snails. Genetic heterozygosity, as determined by starch gel electrophoresis, was greater in uninfected H. anceps relative to infected individuals. These observations combined with the high prevalence (up to 60%), complete castration in patent infections, and the absence of an encapsulation response in infected snails, suggest that factors conferring incompatibility may have been selected for in the H. anceps population within the pond.

Animals↗
PubMed1994

Cyclical behavior of genotype frequencies in a two-locus population under fluctuating haploid selection.

Numerical iterations have shown that periodic haploid two-locus selection with nonoverlapping generations can produce large-scale cyclical behavior with a period differing significantly from the environmental period. Among other types, we observed slowly damping oscillations with very long periods, stable T-cycles with a length containing several environmental periods, and chaotic-like dynamics. Possible biological implications are discussed.

Environment↗
PubMed1975

Assortative mating, linkage and genotypic frequencies.

The effect of introducing assortative mating in a population in linkage equilibrium is considered. It is shown that the introduction of assortative mating will disturb linkage equilibrium which will be re-established at another point independent of the recombination value r but depending upon additive variance and gene frequencies. It is also shown that when equilibrium is established Fisher's (1918) model of assortative mating will be applicable.

Gene Frequency↗
PubMed1999

Glycogen storage disease type II: birth prevalence agrees with predicted genotype frequency.

OBJECTIVES: To compare the overall birth prevalence of diagnosed glycogen storage disease type II (GSD II) with the predicted frequency based on mutation screening, in order to determine whether GSD II is an underdiagnosed condition, and to analyze which medical disciplines recognize GSD II. METHODS: Retrospective data on all enzymatic diagnoses of GSD II were collected from diagnostic labs throughout the Netherlands, covering the period from January 1, 1972 to December 31, 1996. Age-specific diagnostic incidence rates were calculated for the entire study period. By adding together the diagnostic incidences for all age groups, we calculated the birth prevalence of diagnosed GSD II and compared these figures with the predicted frequency based on mutation screening in a random sample from the general population. The medical specialization of the referring clinicians was also recorded. RESULTS: GSD II was diagnosed in 154 individuals, including 11 prenatal diagnoses. The birth prevalences of the various phenotypes were 1/101,000 (infantile form), 1/720,000 (juvenile form) and 1/53,000 (adult form). The birth prevalence of the adult and infantile phenotype together was 1/35,000. Eighty-two percent of the patients were diagnosed in university hospitals. Of the patients with infantile GSD II, 71% were diagnosed by a pediatrician, whereas most patients with adult GSD II were diagnosed by a neurologist (80%). CONCLUSIONS: There is no evidence for the underdiagnosis of GSD II in the Netherlands, as the calculated birth prevalences of the disease are consistent with previous predictions based on mutation screening in a random sample of newborns. The worldwide birth prevalence of the disease may well be higher than 1 in 100,000. GSD II is mainly diagnosed in university hospitals.

Journal Article↗