The physical location of genes cdc2 and prh1 in maize (Zea mays L.).

A biotin-labelling in situ hybridization technique was first used to physically map two single copy genes, cdc2 and prh1, in maize. These two genes are metabolically interrelated genes. The full-length cDNA clones cdc2ZmA and ZmPPI of genes cdc2 and prh1 were adopted as the probes. They are 1.3 and 1.6 kb in size, respectively. Clone cdc2ZmA was physically mapped on the long arm of chromosomes 4, 8, and 9. The percent distances from centromere to detection site were 57.9 +/- 2.7, 28.4 +/- 1.5, and 88.2 +/- 3.3. The detection rate was 19.2%. Clone ZmPPI was physically mapped on the long arm of chromosomes 4, 6, and 8. The percent distances were 53.6 +/- 1.2, 60.8 +/- 2.9 and 17.1 +/- 1.6. The detection ratio was 18.5%. The technique of chromosome ISH and the relationship between the location and function of these two genes have been discussed.