In situ hybridization of two cloned chromosome 7 sequences tightly linked to the cystic fibrosis locus

Two DNA sequences closely linked to the cystic fibrosis locus have been sublocalized to 7q31.3→q32 by in situ hybridization. These findings are consistent with previously published maps of that region of human chromosome 7. The cystic fibrosis locus therefore maps to the 7q31.3→q32 region, a more distal location than had been inferred from previous data.published_or_final_versio

Fluorescence in situ hybridization mapping of the cystic fibrosis transmembrane conductance regulator (CFTR) gene to 7q31.3

We have used the fluorescence in situ hybridization (FISH) technique to refine the localization of the cystic fibrosis transmembrane conductance regulator (CFTR) gene on human chromosome 7. The result shows that the gene is most likely located within band q31.3.published_or_final_versio

Mapping of DNA markers linked to the cystic fibrosis locus on the long arm of chromosome 7

We have used a panel of eight human/mouse somatic-cell hybrids, each containing various portions of human chromosome 7, and three patient cell lines with interstitial deletions on chromosome 7 for localization of six DNA markers linked to the cystic fibrosis locus. Our data suggest that D7S15 is located in the region 7cen→q22, that MET is located in 7q22→31, and that D7S8 and 7C22 are located in q22→q32. The hybridization results for COL1A2 and TCRB are consistent with their previous assignment to 7q21→q22 and 7q32, respectively. Given the location of these six markers and their linkage relationships, it is probable that the cystic fibrosis locus is in either the distal region of band q22 or the proximal region of q31. Using the same set of cell lines, we have also examined the location of another chromosome 7 marker PGY1. The data show that PGY1 is located in the region 7cen→q22, a position very different from its previous assignment.published_or_final_versio

Cystic fibrosis: Progress in mapping the disease locus using polymorphic DNA markers. I.

The conventional approach to the identification of the affected gene in inherited diseases is through the demonstration of specific biochemical abnormalities in patients, their tissues, or cells. This approach has, unfortunately, been unsuccessful in the case of cystic fibrosis (CF), the most common severe autosomal recessive disorder in Causasians. An alternative approach is to locate the CF gene by linkage studies with chromosomal markers. We report here our results of testing 39 DNA restriction fragment length polymorphic (RFLP) markers using a panel of 45 two-generation Canadian families each with two or more affected children. The probability of linkage between each marker and CF was analyzed by the lod score method using the LIPED program. The results of these analyses show that none of the markers tested is closely linked to the disease locus.published_or_final_versio

Assignment of the 5-hydroxytryptamine (serotonin) receptor 5A gene (HTR5A) to human chromosome band 7q36.1

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Localization of the human dihydrolipoamide dehydrogenase gene (DLD) to 7q31→q32

The gene for human dihydrolipoamide dehydrogenase (DLD) has been localized to the long arm of chromosome 7, within bands q31→q32, by gel-blot hybridization analysis with DNA from a panel of somatic cell hybrids containing various portions of human chromosome 7.published_or_final_versio

Cystic fibrosis: analysis of linkage of the disease locus to red cell and plasma protein markers

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Localization of the human gene encoding the 13.3-kDa subunit of mitochondrial complex III (UQCRB) to 8q22 by in situ hybridization

We have localized the human gene encoding the 13.3-kDa subunit of mitochondrial complex III (UQCRB) to chromosome 8 using both radioactive in situ hybridization and fluorescence in situ hybridization. The additional peak obtained with the former method is attributed to the higher sensitivity of this technique, which results in hybridization of the probe to the less conserved pseudogene. We therefore conclude that the functional gene is most likely located at 8q22.published_or_final_versio

The murine cataractogenic mutation, Cat Fraser, segregates independently of the gamma crystallin genes

The murine mutation, Cat Fraser (Cat(Fr)), causes dominantly inherited ocular cataracts. Lenses of adult mice bearing this mutation contain reduced amounts of all seven γ-crystallin proteins and their corresponding transcripts. Levels of other lens proteins and transcripts appear normal and no extra-ocular effects of the mutation have been observed. The selective effect of this mutation on the γ-crystallins is consistent with the possibility that the site at which it occurs is involved in the coordinated regulation of the family of genes which encodes them. We have shown that several restriction fragment length polymorphisms in the γ-crystallin genes segregate independently of the Cat(Fr) mutation. Therefore, despite its selective effect on the expression of the γ-crystallin genes, the mutation is not linked to them. This observation rules out the possibility that the mutation is in a cis-acting regulatory site.published_or_final_versio

A cluster of highly polymorphic dinucleotide repeats in intron 17b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene

A cluster of highly polymorphic dinucleotide repeats has been detected in intron 17b of the CFTR gene, 200 bp downstream from the preceding exon. At least 24 alleles, with sizes ranging from 7 to 56 units of a TA repeat, have been identified in a panel of 92 unrelated carriers of cystic fibrosis (CF). The common ones are those with 7, 30, and 31 dinucleotide units, with frequencies of .22, .19, and .12, respectively, among the non-CF chromosomes. Mendelian, codominant segregation of the alleles has been demonstrated in family studies, as expected. A less polymorphic dinucleotide (CA repeat) cluster has also been detected in a region 167 bp downstream from the TA repeat. The length of the CA repeat cluster varies from 11 to 17 dinucleotide units, and it appears to have an inverse relationship to that of the TA repeats. These dinucleotide repeats should be useful in genetic linkage studies, in counseling for CF families with unknown mutations, and in tracing the origins of the various mutant CF alleles.published_or_final_versio