Molecular and General Genetics MGG

, Volume 198, Issue 2, pp 290–298

Tobacco single-copy DNA is highly homologous to sequences present in the genomes of its diploid progenitors

  • Jack K. Okamuro
  • Robert B. Goldberg

DOI: 10.1007/BF00383009

Cite this article as:
Okamuro, J.K. & Goldberg, R.B. Molec. Gen. Genet. (1985) 198: 290. doi:10.1007/BF00383009


We compared the single-copy DNA sequences of the tetraploid tobacco plant, Nicotiana tabacum, with those of its diploid progenitors N. sylvestris and N. tomentosiformis. We observed that 65% of N. sylvestris and N. tomentosiformis single-copy DNA fragments reacted with each other using moderately stringent hybridization conditions (60° C, 0.18 M Na+). An additional 10% sequence homology was detected when the hybridization temperature was reduced by 10° C. The thermal stability of interspecific single-copy DNA duplexes indicated that they were approximately 6% more mispaired than homologous single-copy DNA duplexes. In contrast, we observed almost no single-copy DNA divergence between N. tabacum and its diploid progenitors. Greater than 99% of N. sylvestris and N. tomentosiformis single-copy DNAs reacted with N. tabacum DNA using moderately stringent hybridization conditions. The thermal stability of these duplexes indicated that they contained no more sequence mismatch than homologous single-copy duplexes. Together, our results show that significant single-copy DNA sequence divergence has occurred between the diploid N. sylvestris and N. tomentosiformis genomes. However, by applying our experimental criteria these single-copy DNAs are indistinguishable from their counterparts in the hybrid N. tabacum nucleus.

Copyright information

© Springer-Verlag 1985

Authors and Affiliations

  • Jack K. Okamuro
    • 1
  • Robert B. Goldberg
    • 1
  1. 1.Department of BiologyUniversity of CaliforniaLos AngelesUSA

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