Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

A variety of epistatic interactions can occur between partially homologous transgene loci brought together by sexual crossing


Epistatic interactions between unlinked transgene loci in tobacco plants were studied following sexual crosses between different transgenic lines. Three potential “modifier” transgene loci, which were structurally similar but integrated at different chromosomal locations, were tested for their ability to influence the expression of a partially homologous “target” transgene locus. After introduction of an individual modifier locus, the target locus could be either unaffected, completely inactivated and methylated or differentially sensitive, showing more complete inactivation and methylation when homozygous than when hemizygous. The implications of these results for inbreeding depression in plants are discussed.

This is a preview of subscription content, log in to check access.


  1. Brink RA, Styles ED, Axtell JD (1968) Paramutation: directed genetic change. Science 59:161–170

  2. Brown PTH (1989) DNA methylation in plants and its role in tissue culture. Genome 31:717–729

  3. Cannon M, Platz J, O'Leary M, Sookdeo C, Cannon F (1990) Organ-specific modulation of gene expression in transgenic plants using antisense RNA. Plant Mol Biol 5:39–47

  4. de Carvalho F, Gheysen G, Kushnir S, Van Montagu M, Inze D, Castresana CJ (1992) Suppression of β(1,3)-glucanase transgene expression in homozygous plants. EMBO J 11:2595–2602

  5. Finnegan EJ, Brettell RIS, Dennis ES (1992) The role of DNA methylation in the regulation of plant gene expression. In: Jost J-P, Saluz HP (eds) DNA Methylation. Birkhauser Press, Basel (in press)

  6. Goring DR, Thomson L, Rothstein SJ (1991) Transformation of a partial nopaline synthase gene into tobacco suppresses the expression of a resident wild-type gene. Proc Natl Acad Sci USA 88:1770–1774

  7. Grierson D, Fray RG, Hamilton AJ, Smith CJS, Watson CP (1991) Does co-suppression of sense genes in transgenic plants involve antisense RNA? Trends Biotechnol 9:122–123

  8. Heslop-Harrison JS, Bennett MD (1990) Nuclear architecture in plants. Trends Genet 6:401–405

  9. Hilliker AJ, Appels R (1989) The arrangement of interphase chromosomes: structural and functional aspects. Exp Cell Res 185:297–318

  10. Hobbs SLA, Kpodar P, DeLong CMO (1990) The effect of T-DNA, copy number, position and methylation on reporter gene expression in tobacco transformants. Plant Mol Biol 15:851–864

  11. Jorgensen R (1990) Altered gene expression in plants due to trans interactions between homologous genes. Trends Biotechnol 8:340–344

  12. Jorgensen R (1991) Beyond antisense — how do transgenes interact with homologous plant genes? Trends Biotechnol 9:288–267

  13. Kricker MC, Drake JW, Radman M (1992) Duplication-targeted DNA methylation and mutagenesis in the evolution of eukaryotic chromosomes. Proc Natl Acad Sci USA 89:1075–1079

  14. van der Krol AR, Mur LA, Beld M, Mol JNM, Stuitje AR (1990) Flavonoid genes in petunia: addition of a limited number of gene copies may lead to a suppression of gene expression. Plant Cell 2:291–299

  15. Linn F, Heidmann I, Saedler H, Meyer P (1990) Epigenetic changes in the expression of the maize A1 gene in Petunia hybrida: role of number of integrated gene copies and state of methylation. Mol Gen Genet 222:329–336

  16. Matzke MA, Matzke AIM (1990) Gene interactions and epigenetic variation in transgenic plants. Dev Genet 11:214–223

  17. Matzke MA, Matzke AIM (1991) Differential inactivation and methylation of a transgene in plants by two suppressor loci containing homologous sequences. Plant Mol Biol 16:821–830

  18. Matzke MA, Primig M, Trnovsky J, Matzke AIM (1989) Reversible methylation and inactivation of marker genes in sequentially transformed tobacco plants. EMBO J 8:643–649

  19. Mol J, van Blokland R, Kooter J (1991) More about co-suppression. Trends Biotechnol 9:182–183

  20. Napoli C, Lemieux C, Jorgensen R (1990) Introduction of a chimeric chalcone synthase gene into petunia results in reversible cosuppression of homologous genes in trans. Plant Cell 2:279–289

  21. Neuhaus J-M, Ahl-Goy P, Hinz U, Flores S, Meins F (1991) High-level expression of a tobacco chitinase gene in Nicotiana sylvestris. Susceptibility of transgenic plants to Cercospora nicotianae infection. Plant Mol Biol 16:141–151

  22. Scheid OM, Paszkowski J, Potrykus I (1991) Reversible inactivation of a transgene in Arabidopsis thaliana. Mol Gen Genet 228:104–112

  23. Selker EU (1990) Premeiotic instability of repeated sequences in Neurospora crassa. Annu. Rev Genet 24:579–613

  24. Selker EU, Garrett PW (1988) DNA sequence duplications trigger gene inactivation in Neurospora crassa. Proc Natl Acad Sci USA 85:6870–6874

  25. Smith CJS, Watson CF, Bird CR, Ray J, Schuch W, Grierson D (1990) Expression of a truncated tomato polygalacturonase gene inhibits expression of the endogenous gene in transgenic plants. Mol Gen Genet 224:477–481

  26. Taylor B, Powell A (1982) Isolation of plant DNA and RNA. Focus 4:4–6

Download references

Author information

Correspondence to M. A. Matzke.

Additional information

Communicated by H. Saedler

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Matzke, M.A., Neuhuber, F. & Matzke, A.J.M. A variety of epistatic interactions can occur between partially homologous transgene loci brought together by sexual crossing. Molec. Gen. Genet. 236, 379–386 (1993).

Download citation

Key words

  • DNA methylation
  • Epistasis
  • Hemizygous/homozygous
  • Inbreeding depression
  • trans-inactivation