High-Resolution Mapping of Human Chromosome 11 by in Situ Hybridization with Cosmid Clones

TLDR

Cosmid clones of human DNA were mapped on chromosome 11 using fluorescence in situ hybridization that suppresses repetitive DNA signals. The authors analyzed 13 known genes, a chromosome‑11 repeat, and 36 random cosmid clones, employing digital imaging microscopy on extended prometaphase chromosomes to achieve high‑resolution mapping. In situ hybridization produced chromosome‑11 maps that matched Southern blot coordinates and, when three or more cosmids were hybridized together, allowed unambiguous gene ordering, proving that high‑resolution human chromosome maps can be rapidly generated by this method.

Abstract

Cosmid clones containing human DNA inserts have been mapped on chromosome 11 by fluorescence in situ hybridization under conditions that suppress signal from repetitive DNA sequences. Thirteen known genes, one chromosome 11-specific DNA repeat, and 36 random clones were analyzed. High-resolution mapping was facilitated by using digital imaging microscopy and by analyzing extended (prometaphase) chromosomes. The map coordinates established by in situ hybridization showed a one to one correspondence with those determined by Southern (DNA) blot analysis of hybrid cell lines containing fragments of chromosome 11. Furthermore, by hybridizing three or more cosmids simultaneously, gene order on the chromosome could be established unequivocally. These results demonstrate the feasibility of rapidly producing high-resolution maps of human chromosomes by in situ hybridization.