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Query: UMLS:C0012872 (DNA marker)
 929 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Our previous linkage analysis suggested that the DNA segment D7S122 is located between MET and D7S8, the two genetic markers that are thought to flank the cystic fibrosis locus (CF). Subsequent chromosome walking experiments revealed that D7S122 in within close distance to another randomly isolated DNA marker, D7S340. To determine the physical relationship among D7S122, D7S340, MET, and D7S8, we have constructed a long-range restriction map of the region containing these four DNA segments, by using DNA from a human/hamster somatic hybrid cell line 4AF-KO15 (containing a single human chromosome 7) and a series of rare-cutting restriction enzymes. The combined results of complete, partial, and double digestion analyses confirm that D7S122 and D7S340 are located between MET and D7S8. The order of these markers is MET-D7S340-D7S122-D7S8, with distance intervals of approximately 500, 10, and 980 kbp, respectively. Together with family analysis, this information will be useful for eventual identification of the CF gene.
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PMID:Physical localization of two DNA markers closely linked to the cystic fibrosis locus by pulsed-field gel electrophoresis. 258 21

Cystic fibrosis (CF) is always a common lethal genetic disease. The locus is localized to human chromosome 7q22-7q31. Genetic linkage between the CF locus and polymorphic DNA marker is used to realize family studies. We have genotyped 56 families (352 patients) with a CF child. The informativeness with the six markers (Met D/Taq I, Met H/Taq I, Met H/Msp 1, XV2c/Taq 1, km19/pst pJ 3.11/Msp 1) is important (96%). The linkage desequilibrium between alleles detected by XV2 c and Km 19 described by Estivill and al, is also showed in our population. The haplotype B (Km 19 = 6.6 kb, XV2 c = 2.1 kb) is present on 84% of our 112 CF chromosomes. We have established the frequencies of the 10 possible genotypes in the pool of the 112 CF chromosomes and in the pool of the normal chromosome and according to Bayes obtained the predictive positive value to be heterozygote. It is possible to precise the genetic counselling in these families.
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PMID:[Analysis of 112 haplotypes carrying the cystic fibrosis gene. Applications in genetic counseling]. 274 72

Three polymorphic DNA marker loci (INT1L1, D7S23 and D7S399) map to a chromosomal region that is very close to the cystic fibrosis (CF) locus in terms of genetic distance. These marker loci have been used to analyse the linkage disequilibrium in 137 CF families from two South European countries (Italy and Spain). The markers can be analysed for differences in linkage disequilibrium more easily in these populations than in North Europeans, in whom the disequilibrium between the allelic systems defined by the probes and CF is much greater and on a "plateau" through the genetic region. The different levels of disequilibrium found in the studied populations suggest that D7S399 and D7S23 are both closer to CF than INT1L1, and provide additional information on the origins and homogeneity of the CF defect.
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PMID:Linkage disequilibrium for DNA haplotypes near the cystic fibrosis locus in two south European populations. 277 58

Friedreich's ataxia is an autosomal recessive disease with progressive degeneration of the central and peripheral nervous system. The biochemical abnormality underlying the disorder has not been identified. Prompted by the success in localizing the mutations causing Duchenne muscular dystrophy, Huntington's disease and cystic fibrosis, we have undertaken molecular genetic linkage studies to determine the chromosomal site of the Friedreich's ataxia mutation as an initial step towards the isolation and characterization of the defective gene. We report the assignment of the gene mutation for this disorder to chromosome 9p22-CEN by genetic linkage to an anonymous DNA marker MCT112 and the interferon-beta gene probe. In contrast to the clinical variation seen for the disorder, no evidence of genetic heterogeneity is observed.
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PMID:Mapping of mutation causing Friedreich's ataxia to human chromosome 9. 289 44

In many genetic disorders, the responsible gene and its protein product are unknown. The technique known as "reverse genetics," in which chromosomal map positions and genetically linked DNA markers are used to identify and clone such genes, is complicated by the fact that the molecular distances from the closest DNA markers to the gene itself are often too large to traverse by standard cloning techniques. To address this situation, a general human chromosome jumping library was constructed that allows the cloning of DNA sequences approximately 100 kilobases away from any starting point in genomic DNA. As an illustration of its usefulness, this library was searched for a jumping clone, starting at the met oncogene, which is a marker tightly linked to the cystic fibrosis gene that is located on human chromosome 7. Mapping of the new genomic fragment by pulsed field gel electrophoresis confirmed that it resides on chromosome 7 within 240 kilobases downstream of the met gene. The use of chromosome jumping should now be applicable to any genetic locus for which a closely linked DNA marker is available.
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PMID:Construction of a general human chromosome jumping library, with application to cystic fibrosis. 295 May 91

A polymorphic DNA marker has been found genetically linked, in a set of 39 human families, to an autosomal recessive gene that causes cystic fibrosis (CF), a disease affecting one in 2000 Caucasian children. The DNA marker (called D0CRI-917) is also linked to the PON locus, which by independent evidence is linked to the CF locus. The best estimates of the genetic distances are 5 centimorgans between the DNA marker and PON and 15 centimorgans between the DNA marker and the CF locus, meaning that the location of the disease gene has been narrowed to about 1 percent of the human genome (about 30 million base pairs). Although the data are consistent with the interpretation that a single locus causes cystic fibrosis, the possibility of genetic heterogeneity remains. The discovery of a linked DNA polymorphism is the first step in molecular analysis of the CF gene and its causative role in the disease.
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PMID:Cystic fibrosis locus defined by a genetically linked polymorphic DNA marker. 299 31

A linkage has been detected between the locus for cystic fibrosis (CF) and the pro alpha 2(I) collagen gene (COL1A2) which is located in the region q21.3----q22.1 of chromosome 7. Based on the combined linkage data derived from 50 informative two-generation nuclear families collected in Canada and Denmark, the distance between COL1A2 and CF is estimated to be 19 centiMorgans. Close linkage has also been detected between COL1A2 and the DNA marker D7S15 (formerly D0CRI-917) and the serum enzyme activity marker paraoxonase (PON), both of which have previously been found linked to CF. The results of the two-point and three-point linkage analyses indicate that the most probable order of these four genetic loci is COL1A2-D7S15 - PON - CF.
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PMID:Linkage of cystic fibrosis to the pro alpha 2(I) collagen gene, COL1A2, on chromosome 7. 301 63

Cloned DNA markers which are closely linked to the gene defect causing cystic fibrosis have recently been described. These markers are sufficiently informative for carrier detection in 80% of families where there is a living cystic fibrosis child and unaffected sibs. The tightly linked DNA marker pJ3.11 was used in this study to identify carriers in six families and exclude carrier status in two subjects. Risk calculations for recessive diseases using linked DNA probes may be complex, but useful information for counselling can be obtained in this way.
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PMID:Cystic fibrosis carrier detection using a linked gene probe. 301 47

A collaborative study involving seven research groups provided an opportunity to investigate the linkage relationships between cystic fibrosis and two DNA marker loci, MET and pJ3.11 (D7S8), on an extended sample of 211 tested families. The maximum lod scores, recombination estimates, and confidence upper bounds (in parentheses) were 91.0 at theta = .004 (.012) for CF and MET, 71.3 at theta = .003 (.011) for CF and D7S8, and 69.3 at theta = .018 (.036) for MET and D7S8. Three-locus analyses yielded best support for the order MET-CF-D7S8, with odds against the alternate orders CF-MET-D7S8 and CF-D7S8-MET of 9:1 and 161:1, respectively. However, the number of observed recombinants was small and only one of the recombinants was jointly informative for all three markers. Significant allelic association was found between CF and both MET and D7S8. Weaker association between the latter two loci is consistent with the order MET-CF-D7S8.
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PMID:Linkage of cystic fibrosis to two tightly linked DNA markers: joint report from a collaborative study. 302 71

The gene for the alpha i1 subunit of human guanine nucleotide binding (G) protein was mapped by in situ hybridization to chromosome 7 at band q21. The regional chromosomal location of the human alpha i1 gene was confirmed using human/mouse somatic-cell hybrid lines containing portions of human chromosome 7. Because the alpha i1 gene mapped near the cystic fibrosis locus and because an abnormal G protein might be expected to contribute to the pathophysiology of this disease, the alpha i1 gene was mapped with respect to the cystic fibrosis locus as defined by the Met oncogene and anonymous DNA marker pJ3.11. The location of the alpha i1 gene proved to be distinct from that of the cystic fibrosis locus.
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PMID:The gene for the alpha i1 subunit of human guanine nucleotide binding protein maps near the cystic fibrosis locus. 313 Jul 52


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