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. 1997 Sep;147(1):315–320. doi: 10.1093/genetics/147.1.315

Dissection of a Synthesized Quantitative Trait to Characterize Transgene Interactions

J P Nap 1, A J Conner 1, L Mlynarova 1, W J Stiekema 1, R C Jansen 1
PMCID: PMC1208115  PMID: 9286691

Abstract

Six transgenic tobacco lines, each homozygous for the β-glucuronidase (GUS) gene at a different locus, and wild type were selfed and intercrossed to evaluate GUS activity in all possible hemizygous, homozygous and dihybrid combinations of GUS alleles. The transgenic lines are characterized by their GUS activity (two low, three intermediate, one high), T-DNA complexity (four single-copy, two more complex single-locus) and the presence of the chicken lysozyme matrix-associated region (MAR) around the full T-DNA (two lines). Gene action and interaction was analyzed by weighted linear regression with parameters for additivity, dominance and epistasis. The analysis showed that each of the four single-copy lines acted fully additively. In contrast, the two complex single-locus lines showed classical single-locus overdominance and were epistatic dominant over all other GUS alleles. The latter is manifested in severe suppression of GUS activity in dihybrid lines, irrespective of the presence of MAR elements around the GUS gene. Such elements apparently do not protect against epistatic dominance. The quantitative data suggested that the epistatic dominance and overdominance are based on the same molecular mechanism. Our approach of a genetic analysis of quantitative variation in well-characterized transgenic lines provides a powerful tool to gain insight into complex plant traits.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Assaad F. F., Tucker K. L., Signer E. R. Epigenetic repeat-induced gene silencing (RIGS) in Arabidopsis. Plant Mol Biol. 1993 Sep;22(6):1067–1085. doi: 10.1007/BF00028978. [DOI] [PubMed] [Google Scholar]
  2. Fijneman R. J., de Vries S. S., Jansen R. C., Demant P. Complex interactions of new quantitative trait loci, Sluc1, Sluc2, Sluc3, and Sluc4, that influence the susceptibility to lung cancer in the mouse. Nat Genet. 1996 Dec;14(4):465–467. doi: 10.1038/ng1296-465. [DOI] [PubMed] [Google Scholar]
  3. Frankel W. N., Schork N. J. Who's afraid of epistasis? Nat Genet. 1996 Dec;14(4):371–373. doi: 10.1038/ng1296-371. [DOI] [PubMed] [Google Scholar]
  4. Hobbs S. L., Warkentin T. D., DeLong C. M. Transgene copy number can be positively or negatively associated with transgene expression. Plant Mol Biol. 1993 Jan;21(1):17–26. doi: 10.1007/BF00039614. [DOI] [PubMed] [Google Scholar]
  5. Matzke M. A., Matzke AJM. How and Why Do Plants Inactivate Homologous (Trans)genes? Plant Physiol. 1995 Mar;107(3):679–685. doi: 10.1104/pp.107.3.679. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Mlynarova L., Jansen R. C., Conner A. J., Stiekema W. J., Nap J. P. The MAR-Mediated Reduction in Position Effect Can Be Uncoupled from Copy Number-Dependent Expression in Transgenic Plants. Plant Cell. 1995 May;7(5):599–609. doi: 10.1105/tpc.7.5.599. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Mlynarova L., Loonen A., Heldens J., Jansen R. C., Keizer P., Stiekema W. J., Nap J. P. Reduced Position Effect in Mature Transgenic Plants Conferred by the Chicken Lysozyme Matrix-Associated Region. Plant Cell. 1994 Mar;6(3):417–426. doi: 10.1105/tpc.6.3.417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Nap J. P., Dirkse W. G., Louwerse J., Onstenk J., Visser R., Loonen A., Heidekamp F., Stiekema W. J. Analysis of the region in between two closely linked patatin genes: class II promoter activity in tuber, root and leaf. Plant Mol Biol. 1992 Nov;20(4):683–694. doi: 10.1007/BF00046453. [DOI] [PubMed] [Google Scholar]
  9. Patterson M., Todd J. A. A complex issue. Trends Genet. 1995 Dec;11(12):463–463. doi: 10.1016/s0168-9525(00)89153-2. [DOI] [PubMed] [Google Scholar]
  10. Peach C., Velten J. Transgene expression variability (position effect) of CAT and GUS reporter genes driven by linked divergent T-DNA promoters. Plant Mol Biol. 1991 Jul;17(1):49–60. doi: 10.1007/BF00036805. [DOI] [PubMed] [Google Scholar]
  11. Tanksley S. D. Mapping polygenes. Annu Rev Genet. 1993;27:205–233. doi: 10.1146/annurev.ge.27.120193.001225. [DOI] [PubMed] [Google Scholar]

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