The gene for pancreatic polypeptide (PPY) and the anonymous marker D17S78 are within 45 kb of each other on chromosome 17q21
- Univ. of Michigan Medical Center, Ann Arbor, MI (United States)
- Univ. of California, Berkeley, CA (United States)
- Univ. of Texas Southwestern Medical Center, Dallas, TX (United States)
A gene for early-onset breast and ovarian cancer (BRCA1) has been localized to a small region of chromosome 17q21. A combination of genetic linkage studies, radiation-reduced hybrid analysis, and physical mapping by FISH has identified several genes/markers that lie in this interval. Among these are the gene encoding pancreatic polypeptide (PPY) and a polymorphic marker at locus D17S78. Efforts to construct a physical map of this region by isolating a large number of yeast artificial chromosome (YAC) and cosmid clones demonstrate that PPY and D17S78 are present within the same cosmid clone, and therefore no farther than 45 kb apart. This observation takes on particular significance since it excludes a recently described BRCA1 candidate gene from the interval defined by meiotic mapping. Although PPY and D17S78 were found to be no farther than 45 kb apart, identification of a smaller fragment that hybridizes to both probes would indicate that these two are much closer. The probe p131 and the gene PPY were previously mapped to 17q21-q23 and to the proximal long arm of chromosome 17, respectively. The demonstration of the close proximity of these markers should allow them to be treated as a single locus in terms of long-range genomic mapping of this region, and the genomic clones isolated should serve as useful resources for the identification of the BRCA1 gene. Analysis of a large number of a familial and spordic breast and ovarian cancers has identified frequent loss of heterozygosity near the BRCA1 locus. A recent report has suggested the responsible interval lies just telomeric to PPY, and a suggested candidate gene (MCD) for BRCA1 was found to be somatically rearranged in two of several hundred sporadic breast tumors.
- OSTI ID:
- 6811056
- Journal Information:
- Genomics; (United States), Vol. 21:2; ISSN 0888-7543
- Country of Publication:
- United States
- Language:
- English
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