identification of human chromosome segments that have high homology with rat genomic dna

this study was conducted to determine the location of dna segment with homology to the rat conserved genomic dna in human chromosomes. the labeled rat genomic dna was hybridized with normal human (male) metaphases. the study of 74 metaphases after fluorescence in situ hybridization showed 371 twin-spot signals on human chromosomes. statistical analysis indicated that the specific accumulation of signals on 1q22-qter, 2p2, 3p21-p23, 4q3, 6q2, 8p12-pter, 11p12-pter, 11q12-qter, 12q2, 13p, 15p, 16q2, 21q12-qter, yq1-qter, and xq2 was not random. results of stepwise multiple linear regressions indicated that number of mapped oncogenes (beta = 1.092 t = 7.552 p<0.001) and density of mapped oncogenes on chromosomes (beta = -0.832 t = -5.751 p<0.001) have significant effects on number of double-spots on human chromosomes. these data reflects the evolutionary conservation between rat dna and human dna at the above-mentioned bands