PRICE, H. JAMES*, M. NURUL ISLAM-FARIDI, AND DAVID M. STELLY. Department of Soil and Crop Sciences, Texas A&M University, College Station, TX 77843-2474. - Molecular cytogenetic mapping of sorghum chromosome 1.
Fluorescent in situ hybridization (FISH) of cloned probes provides a
powerful tool for the integration of recombination, physical and
cytogenetic maps. As part of a sorghum genomics project we have
assigned the position of eight cloned DNA sequences to chromosome 1 of
Sorghum bicolor . The probes used included a
centromere-associated repeat, 28S-18S rDNA, a corn pollen-expressed
Adh cDNA-selected sorghum bacterial artificial chromosome
(BAC), and five RFLP-selected sorghum BACs. With the exception of the
centromere-associated sequence and the 28S-18s rDNA, the probes
produced FISH sites at the ends of the chromosome. The BACs selected
from probes used to map two adjacent RFLP loci produced FISH signals
at opposite ends of the chromosome. Over 85% of the physical length of
this chromosome corresponded to approximately 12 map units separating
the two RFLP loci. This indicates that most of the recombination and
the loci of the ca. 120 cM RFLP map are located at the ends of the
chromosome. Research supported by the Texas Advanced Technology and
Research Program (grant 999902-090 to HJP and DMS), the Texas
Agricultural Experiment Station, and the Texas A&M University Office
of University Research.
Key words: chromosome 1, FISH, molecular cytogenetics, Sorghum bicolor