ISOLATION OF DNA FRAGMENTS FROM CHROMOSOME 13

A number of patients with retinoblastoma have a deletion of chromosome 13. Comparison of the deleted segments from different individuals reveals that all deletions involve chromosome band 13q14. This observation has lead to the hypothesis that in this region is a gene of genes important in the etiology of retinoblastoma. As a first step toward understanding those genes, the authors successfully isolated five DNA fragments from chromosome 13 using recombinant DNA techniques. The DNA fragments from chromosome 13 will be useful in identifying DNA polymorphic sites that are linked to the retinoblastoma locus tentatively assigned to 13q14. Such DNA polymorphisms will be important in the genetic counselling of families with retinoblastoma. These chromosome 13q14 fragments also may be useful in searching for microdeletions of 13q14.