Chromosomal analysis of Nicotiana asymmetric somatic hybrids by dot blotting and in situ hybridization.
A species-specific, dispersed repetitive DNA sequence was cloned from Nicotiana plumbaginifolia and used in dot blots and in situ hybridizations to analyze asymmetric somatic hybrids of N. tabacum(+)kanamycin-resistant N. plumbaginifolia. Dot blot hybridization data, using the cloned, species-specific repetitive DNA as a probe, showed that some of the hybrids contain only 1%-5% N. plumbaginifolia DNA, whereas others contain 15%-25%. In situ hybridization of the probe to chromosome spreads showed that the extremely asymmetric hybrids retain a single N. plumbaginifolia chromosome; the hybrids with higher dot blot values were found to have 8 to 12 N. plumbaginifolia chromosomes and chromosome fragments. In situ hybridization also revealed translocations between N. plumbaginifolia and N. tabacum chromosomes in 3 of 8 hybrids studied. RFLP analysis using a 5S gene probe showed the presence of N. plumbaginifolia-specific 5S banding patterns in most hybrids examined, including those that retain only a single N. plumbaginifolia chromosome.
Piastuch
W C
WC
Department of Biological Science, Florida State University, Tallahassee 32306.
Bates
G W
GW
D002875:Chromosomes; D003001:Cloning, Molecular; D004247:DNA / Q000032:analysis; D007621:Karyotyping; D009693:Nucleic Acid Hybridization; D010947:Plants, Toxic; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid; D014026:Nicotiana / Q000235:genetics*; D014178:Translocation, Genetic
D004247:DNA