Peer Reviewed Research Articles

80. Wu, F., Shi, X., Li, X., Li, Y., Chong, K., Theißen, G., Meng, Z. (2017).
The ABCs of flower development: mutational analysis of AP1/FUL-like genes in rice provides evidence for a homeotic (A)-function in grasses.
Plant J. 89, 310 - 324External link.

79. Lenser, T., Graeber, K., Cevik, Ö.S., Adigüzel, N., Dönmez, A.A., Grosche, C., Kettermann, M., Mayland-Quellhorst, S., Mérai, Z., Mohammadin, S., Nguyen, T.-P., Rümpler, F., Schulze, C., Sperber, K., Steinbrecher, T., Wiegand, N., Strnad, M., Mittelsten Scheid, O., Rensing, S.A., Schranz, M.E., Theißen, G., Mummenhoff, K., Leubner-Metzger, G.. (2016).
Developmental control and plasticity of fruit and seed dimorphism in Aethionema arabicum.
Plant Physiol. 172, 1691-1707External link.

78. Schilling, S., Gramzow, L., Lobbes, D., Kirbis, A., Weilandt, L.,  Hoffmeier, A., Junker, A., Weigelt-Fischer, K., Klukas, C., Wu, F., Meng, Z., Altmann, T., Theißen, G. (2015).
Non-canonical structure, function and phylogeny of the Bsister MADS-box gene OsMADS30 of rice (Oryza sativa).
Plant J. 84, 1059-1072External link.

77. Rümpler, F., Gramzow, L., Theißen, G. und Melzer, R. (2015).
Did convergent protein evolution enable phytoplasmas to generate ‘zombie plants’?
Trends Plant Sci. 20, 798-806.External link

76. Gramzow L., Theißen, G. (2015).
Phylogenomics reveals surprising sets of essential and dispensable clades of MIKCc-group MADS-box genes in flowering plants.
Journal of Experimental Zoology Part B: Molecular and Developmental Evolution 324B, 353-362.External link

75. Puranik, S., Acajjaoui, S., Conn, S.,  Costa, L., Conn, V., Vial, A., Marcellin, R.,  Melzer, R., Brown, E., Hart, D., Theißen, G., Silva, S.S., Parcy, F., Dumas, R., Nanao, M., Zubieta, C. (2014).
Structural basis for the oligomerization for the MADS domain transcription factor SEPALLATA3 in Arabidopsis.
Plant Cell 26, 3603-3615.External link

74. Jetha, K., Theißen, G., Melzer, R. (2014).
Arabidopsis SEPALLATA proteins differ in cooperative DNA-binding during the formation of floral quartet-like complexes.
Nucleic Acids Research 42, 10927-10942.  External link

73. Kirsch, R., Gramzow, L., Theißen, G., Siegfried, B.D., ffrench-Constant, R.H., Heckel, D.G., Pauchet, Y. (2014).
Horizontal gene transfer and functional diversification of plant cell wall degrading polygalacturonases: key events in the evolution of herbivory in beetles.
Insect Biochemistry and Evolution 52, 33-50.External link

72. Melzer, R., Härter, A., Rümpler, F., Kim, S., Soltis, P.S., Soltis, D.E., Theißen, G. (2014).
DEF- and GLO-like proteins may have lost most of their interaction partners during angiosperm evolution.
Annals of Botany 114, 1431-1443.External link

71. Gramzow, L., Weilandt, L., Theißen, G. (2014).
MADS goes genomic in conifers - towards determining the ancestral set of MADS-box genes in seed plants.
Annals of Botany 114, 1407-1429.External link

70. Lin, X., Wu., F., Du, X., Shi, X., Liu, Y., Liu, S., Hu, Y., Theißen, G., Meng, Z. (2014).
The pleiotropic SEPALLATA-like gene OsMADS34 reveals that the 'empty glumes' of rice (Oryza sativa) spikelets are in fact rudimentary lemmas.
New Phytologist 202, 689-702.External link

69. Hameister, S., Nutt, P., Theißen, G., Neuffer, B. (2013).
Mapping a floral trait in Shepherds purse - 'Stamenoid petals' in natural populations of Capsella bursa-pastoris (L.) Medik.
Flora 208, 641-647.

68. Gramzow, L., Theißen, G. (2013).
Phylogenomics of MADS-box genes in plants - two opposing life styles in one gene family.
Biology 2, 1150-1164.

67. Lenser, T., Theißen, G. (2013).
Conservation of fruit dehiscence pathways between Lepidium campestre and Arabidopsis thaliana sheds light on the regulation of INDEHISCENT.
Plant Journal 76, 545-556.

66. Ruelens, P., de Maagd, R.A., Proost, S., Theißen, G., Geuten, K., Kaufmann, K. (2013).
Flowering Locus C in monocots and the tandem origin of angiosperm-specific MADS-box genes.
Nature Communications 4, 2280.

65. Nystedt, B., Street, N.R., Wetterbom, A., Zuccolo, A., Lin, Y.C., Scofield, D.G., Vezzi, F., Delhomme, N., Giocomello, S.,  Alexeyenko, A., Vicedomini, R., Sahlin, K., Sherwood, E., Eldstrand M., Gramzow, L., Holmberg, K., Hällman, J., Keech, O., Klasson, L., Koriabine, M., Kucukoglu, M., Käller, M., Luthman, J., Lysholm, F., Niittylä, T., Olson, A., Rilakovic, N., Ritland, C., Rosselló, J.A., Sena, J., Svensson, T., Talavera-López, C., Theißen, G., Tuominen, H., Vanneste, K., Wu, Z.Q., Zhang, B., Zerbe, P., Arvestad, L., Bhalerao, R., Bohlmann, J., Bousquet, J., Garcia Gil, R., Hvidsten, T.R., de Jong, P., Mackay, J., Morgante M., Ritland, K., Sundberg, B., Lee Thompson, S., Van de Peer, Y., Andersson, B., Nilsson, O., Ingvarsson, P.K., Lundeberg, J., Jansson, S. (2013).
The Norway spruce genome sequence and conifer genome evolution. 
Nature 497, 579-584.

64. Liu, Y., Cui, S., Wu, F., Yan, S., Lin, X., Du, X., Chong, K., Schilling, S., Theißen, G., Meng, Z. (2013).
Functional conservation of MIKC*-type MADS box genes in Arabidopsis and rice pollen maturation. 
Plant Cell 25, 1288-1303.

63. Lange, M., Orashakova, S., Lange, S., Melzer, R., Theißen, G., Smyth, D.R., Becker, A. (2013).
The seirena B class floral homeotic mutant of California Poppy (Eschscholzia californica) reveals a function of the enigmatic PI motif in the formation of specific multimeric MADS domain protein complexes. 
Plant Cell 25, 438-453.

62. Mühlhausen, A., Lenser, T., Mummenhoff, K., Theißen, G. (2013).
Evidence that an evolutionary transition from dehiscent to indehiscent fruits in Lepidium (Brassicaceae) was caused by a change in the control of valve margin identity genes. 
Plant Journal 73, 824-835.

61. Yang, X., Wu, F., Lin, X., Cui, D., Du, X., Chong, K., Gramzow, L., Schilling, S., Becker, A., Theißen, G., Meng, Z. (2012).
Live and let die - the Bsister MADS-box gene OsMADS29 controls the degeneration of cells in maternal tissues during seed development of rice (Oryza sativa).
PLoS One 7, e51435.

60. Pohl, M., Theißen, G. and Schuster, S. (2012).
GC content dependency of open reading frame prediction via stop codon frequencies.
Gene 511, 441-446. 

59. Kottenhagen, N., Gramzow, L., Horn, F., Pohl, M. and Theißen, G. (2012).
Polyglutamine and polyalanine tracts are enriched in transcription factors of plants.
German Conference on Bioinformatics 2012, pp. 93 - 107.

58. Gramzow, L., Barker, E., Schulz, C., Ambrose, B., Ashton, N., Theißen, G. and Litt A. (2012).
Selaginella genome analysis - entering the "homoplasy heaven" of the MADS world.
Frontiers Plant Sci. 3, 214. 

57. Galimba, K.D., Tolkin, T.R., Sullivan, A.M., Melzer, R., Theißen, G. and Di Stilio, V.S. (2012).
Loss of deeply conserved C-class floral homeotic gene function and C- and E-class protein interaction in a double-flowered ranunculid mutant.
Proc. Natl. Acad. Sci. USA 109, 13478 (Summary), E2267-2275 (article)

56. Wingen, L.U., Münster, T., Faigl, W., Deleu, W., Sommer, H., Saedler, H. and Theißen, G. (2012).
Molecular genetic basis of pod corn (Tunicate maize).
Proc. Natl. Acad. Sci. USA 109, 7115-7120.

55. Mondragón-Palomino and Theißen, G. (2011).
Conserved differential expression of paralogous DEFICIENS- and GLOBOSA-like MADS-box genes in the flowers of Orchidaceae: refining the 'orchid code'.
Plant Journal 66, 1008-1019.

54. Wang, Y.-Q., Melzer, R. and Theißen, G. (2011).
A double-flowered variety of lesser periwinkle (Vinca minor fl. pl.) that has persisted in the wild for more than 160 years.
Annals of Botany 107, 1445-1452.

53. Banks, J.A., Nishiyama, T., Hasebe, M., Bowman, J.L., Gribskov, M., dePamphilis, C., Albert, V.A., Aono, N., Aoyama, T., Ambrose, B.A., Ashton, N.W., Axtell, M.J., Barker, E., Barker, M.S., Bennetzen, J.L., Bonawitz, N.D., Chapple, C., Cheng, C., Correa, L.G.G., Dacre, M., DeBarry, J., Dreyer, I., Elias, M., Engstrom, E.M., Estelle, M., Feng, L Finet, C., Floyd, S.K., Frommer, W.B; Fujita, T., Gramzow, L., Gutensohn, M., Harholt, J., Hattori, M., Heyl, A., Hirai, T., Hiwatashi, Y., Ishikawa, M., Iwata, M., Karol, K.G., Koehler, B., Kolukisaoglu, U., Kubo, M., Kurata, T., Lalonde, S.,  Li, K., Li, Y., Litt, A., Lyons, E.,  Manning, G., Maruyama, T., Michael, T.P, Mikami, K., Miyazaki, S., Morinaga, S-I., Murata, T., Mueller‐Roeber, B., Nelson, D.R., Obara, M., Oguri, Y., Olmstead, R.G., Onodera, N., Petersen, B.L., Pils, B., Prigge, M., Rensing, S.A., Riaño-Pachón, D.M., Roberts, A.W., Sato, Y., Scheller, H.V., Schulz, B., Schulz, Ch., Shakirov, E.V., Shibagaki, N., Shinohara, N., Shippen, D.E., Sørensen, I., Sotooka, R., Sugimoto, N., Sugita, M., Sumikawa, N., Tanurdzic, M., Theißen, G., Ulvskov, P., Wakazuki, S., Weng, J-K., Willats, W.W.G.T., Wipf, D., Wolf, P.G., Yang, L., Zimmer, A.D., Zhu, Q., Mitros, T., Hellsten, U., Loqué, D., Otillar, R., Salamov, A., Schmutz, J., Shapiro, H., Lindquist, E., Lucas, S., Rokhsar, D. and I.V. Grigoriev (2011).
The Selaginella genome identifies genetic changes associated with the evolution of vascular plants.
Science 332, 960-963.

52. Thieme, C.J., Gramzow, L., Lobbes, F. and Theißen, G. (2011).
SplamiR - prediction of spliced miRNAs in plants.
Bioinformatics 27, 1215-1223.

51. Ritz, C.M., Köhnen, I., Groth, M., Theißen, G. and Wissemann, V. (2011).
To be or not to be the odd one out - Allele-specific transcription in pentaploid dogroses (Rosa L. sect. Caninae (DC.) Ser).
BMC Plant Biology 11, 37.

50.  Wang, Y.-Q., Melzer, R. and Theißen, G. (2010).
Interaction patterns of orthologues of floral homeotic proteins from the gymnosperm Gnetum gnemon provide a clue to the origin of 'floral quartets'.
Plant Journal 64, 177-190.

49.  Erdmann, R., Gramzow, L., Melzer, R., Theißen, G. and Becker, A. (2010).
GORDITA (AGL63) is a young paralog of the Arabidopsis thaliana Bsister MADS box gene ABS (TT16) that has undergone neofunctionalization.
Plant Journal 63, 914-924.

48.  Schuster, S. Kreft, J.-U., Brenner, N., Wessely, F., Theißen, G., Ruppin, E. and Schroeter, A.  (2010).
Cooperation and cheating in microbial exoenzyme production -Theoretical analysis for biotechnological applications.
Biotechnology Journal 5, 751-758.

47. Gramzow, L., Ritz, M. and Theißen, G. (2010).
On the origin of MADS-domain transcription factors.
Trends in Genetics 26, 149-153.

46. Cui, R., Han, J., Zhao, S., Su, K., Wu, F., Du, X., Xu, Q., Chong, K., Theißen, G. and Meng, Z. (2010).
Functional conservation and diversification of class E floral homeotic genes in rice (Oryza sativa).
Plant Journal 61, 767-781. External link

45. Ziermann, J., Ritz, M., Hameister, S., Abel, C., Hoffmann, M.H., Neuffer, B. and Theißen, G. (2009).
Floral visitation and reproductive traits of Stamenoid petals, a naturally occuring floral homeotic variant of Capsella bursa-pastoris (Brassicaceae).
Planta 230, 1239-1249.External link

44. Mondragón-Palomino, M., Hiese, L., Härter, A., Koch, M.A. and Theißen G. (2009).
Positive selection and ancient duplications in the evolution of class B floral homeotic genes of orchids and grasses.
BMC Evolutionary Biology 9, 81.External link

43. Melzer, R. and Theißen, G. (2009).
Reconstitution of 'floral quartets' in vitro involving class B and class E floral homeotic proteins.
Nucleic Acids Research 37, 2723-2736.External link

42. Lenser, T., Theißen G. and Dittrich P. (2009)
Developmental robustness by obligate interaction of class B floral homeotic genes and proteins.
PLoS Computational Biology 5, e1000264External link

41. Melzer, R., Verelst, W. and Theißen, G. (2009).
The class E floral homeotic protein SEPALLATA3 is sufficient to loop DNA in 'floral quartet'-like complexes in vitro.
Nucleic Acids Research 37, 144-157.External link

40. Su, K., Zhao, S., Shan, H., Kong, H., Lu, W., Theissen, G., Chen, Z. and Meng, Z. (2008).
The MIK region rather than the C-terminal domain of AP3-like class B floral homeotic proteins determines functional specificity in the development and evolution of petals.
New Phytologist 178, 544-558.External link

39. Bartholmes, C., Nutt, P. and Theißen G. (2008).
Germline transformation of Shepherd's purse (Capsella bursa-pastoris) by the 'floral dip' method as a tool for evolutionary and developmental biology.
Gene 409, 11-19.External link

38. Kanno, A., Hirai, M., Ochiai, T., Simon, H. and Theissen, G. (2007).
Reduced expression of DEFICIENS-like genes in the sepaloid tepals of viridiflora tulips.
Acta Horticulturae 763, 43-48External link.

37.Geuten, K., Becker, A., Kaufmann, K., Caris, P., Janssens, S., Viaene, T., Theissen, G. and Smets, E. (2006).
Petaloidy and petal identity MADS-box genes in the balsaminoid genera Impatiens and Marcgravia.
Plant Journal 47, 501-518External link.

36.De Bodt, S., Theissen, G. and Van de Peer, Y. (2006).
Promoter analysis of MADS-box genes in eudicots through phylogenetic footprinting.
Molecular Biology and Evolution 23, 1293-1303External link.

35. Zahn, L.M., Leebens-Mack, J., Arrington, J.M., Hu, Y., Landherr, L., dePamphilis, C., Becker, A., Theissen, G. and Ma, H. (2006).
Conservation and divergence in the AGAMOUS subfamily of MADS-Box genes: evidence of independent sub- and neofunctionalization events.
Evolution & Development 8, 30-45External link.

34. Kaufmann, K., Anfang, N., Saedler, H. and Theißen, G. (2005).
Mutant analysis, protein-protein interactions and subcellular localization of the Arabidopsis Bsister (ABS) protein.
Molecular Genetics and Genomics 274, 103-118External link.

33. Li, G.-S., Meng, Z., Kong, H.-Z., Chen, Z.-D., Theissen G. and Lu, A.-M. (2005).
Characterization of candidate class A, B, and E floral homeotic genes from the perianthless basal angiosperm Chloranthus spicatus (Chloranthaceae).
Dev. Genes Evol. 215, 437-449External link.

32. Tanabe, Y., Hasebe, M., Sekimoto, H., Nishiyama, T., Kitani, M., Henschel, K., Münster, T., Theissen, G., Nozaki, H. and Ito, M. (2005).
Characterization of MADS-box genes in charophycean green algae and its implication for the evolution of MADS-box genes.
Proc. Natl. Acad. Sci. USA 102, 2436-2441External link.

31. Nam, J., Kaufmann, K., Theißen, G. and Nei, M. (2005).
A simple method for predicting the functional differentiation of duplicate genes and its application to MIKC-type MADS-box genes.
Nucleic Acids Research 33, e12External link.

30. Becker, A., Saedler, H. and Theißen, G. (2003).
Distinct MADS-box gene expression patterns in the reproductive cones of the gymnosperm Gnetum gnemon.
Dev. Genes Evol. 213, 567-572External link.

29. Vandenbussche, M., Theissen, G., van de Peer, Y and Gerats, T. (2003).
Structural diversification and neo-functionalization during floral MADS-box gene evolution by C-terminal frameshift mutations.
Nucl. Acids Res. 31, 4401-4409External link.

28. Kanno, A., Saeki, H., Kameya, T., Saedler, H. and Theißen, G. (2003).
Heterotopic expression of class B floral homeotic genes supports a modified ABC model for tulip (Tulipa gesneriana).
Plant Mol. Biol. 52, 831-841External link.

27. De Bodt, S., Raes, J., Florquin, K., Rombauts, S., Rouzé, P., Theißen, G. and Van de Peer, Y. (2003).
Genomewide structural annotation and evolutionary analysis of the type I MADS-box genes in plants.
J. Mol. Evol. 56, 573-586External link.

26. Münster, T., Deleu, W., Wingen, L.U., Cacharrón, J., Ouzunova, M., Faigl, W., Werth, S., Kim, J.T.T., Saedler, H. and Theißen, G. (2002).
Maize MADS-box genes galore.
Maydica 47, 287-301.

25. Becker, A., Bey, M., Bürglin, T.R., Saedler, H. and Theißen, G. (2002).
Ancestry and diversity of BEL1-like homeobox genes revealed by gymnosperm (Gnetum gnemon) homologs.
Dev. Genes Evol. 212, 452-457External link.

24. Münster, T., Faigl, W., Saedler, H. and Theißen, G. (2002).
Evolutionary aspects of MADS-box genes in the eusporangiate fern Ophioglossum.
Plant Biol. 4, 474-483External link.

23. Winter, K.-U., Saedler, H. and Theißen, G. (2002).
On the origin of class B floral homeotic genes: functional substitution and dominant inhibition in Arabidopsis by expression of an ortholog from the gymnosperm Gnetum.
Plant J. 31, 457-475External link.

22. Henschel, K., Kofuji, R., Hasebe, M., Saedler, H., Münster, T. and Theißen, G. (2002).
Two ancient classes of MIKC-type MADS-box genes are present in the moss Physcomitrella patens.
Mol. Biol. Evol. 19, 801-814External link.

21. Winter, K.-U., Weiser, C., Kaufmann, K., Bohne, A., Kirchner, C., Kanno, A., Saedler, H. and Theißen, G. (2002).
Evolution of class B floral homeotic proteins: obligate heterodimerization originated from homodimerization.
Mol. Biol. Evol. 19, 587-596External link.

20. Becker, A., Kaufmann, K., Freialdenhoven, A., Vincent, C., Li, M.A., Saedler, H. and Theißen, G. (2002).
A novel MADS-box gene subfamily with a sister-group relationship to class B floral homeotic genes.
Mol. Genet. Genomics 266, 942-950External link.

19. Münster, T., Wingen, L.U., Faigl, W., Werth, S., Saedler, H. and Theißen, G. (2001).
Characterization of three GLOBOSA-like MADS-box genes from maize: evidence for ancient paralogy in one class of floral homeotic B-function genes of grasses.
Gene 262, 1-13External link.

18. Becker, A., Winter, K.-U., Meyer, B., Saedler, H. and Theißen, G. (2000).
MADS-box gene diversity in seed plants 300 million years ago.
Mol. Biol. Evol. 17, 1425-1434External link.

17. Mouradov, A., Hamdorf, B., Teasdale, R.D., Kim, J., Winter, K.-U. and Theißen, G.(1999).
A DEF/GLO-like MADS-box gene from a gymnosperm: Pinus radiata contains an ortholog of angiosperm B class floral homeotic genes.
Dev. Genet. 25, 245-252External link.

16. Sundström, J., Carlsbecker, A., Svensson, M.E., Svenson, M., Johanson, U., Theißen, G. and Engström, P. (1999).
MADS-box genes active in developing pollen cones of Norway spruce (Picea abies) are homologous to the B-class floral homeotic genes in angiosperms.
Dev. Genet. 25, 253-266External link.

15. Winter, K.-U., Becker, A., Münster, T., Kim, J.T., Saedler, H. and Theißen, G.(1999).
MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants.
Proc. Natl. Acad. Sci. USA 96, 7342-7347External link.

14. Cacharrn, J., Saedler, H. and Theißen, G. (1999).
Expression of MADS box genes ZMM8 and ZMM14 during inflorescence development of Zea mays discriminates between the upper and the lower floret of each spikelet.
Dev. Genes Evol. 209, 411-420External link.

13. Münster, T., Pahnke, J., Di Rosa, A., Kim, J.T., Martin, W., Saedler, H. and Theißen, G. (1997).
Floral homeotic genes were recruited from homologous MADS-box genes preexisting in the common ancestor of ferns and seed plants.
Proc. Natl. Acad. Sci. USA 94, 2415-2420External link.

12. Theißen, G., Kim, J. and Saedler, H. (1996).
Classification and phylogeny of the MADS-box multigene family suggest defined roles of MADS-box gene subfamilies in the morphological evolution of eukaryotes.
J. Mol. Evol. 43, 484-516External link.

11. Fischer, A., Baum, N., Saedler, H. and Theißen, G. (1995).
Chromosomal mapping of MADS-box genes in Zea mays reveals dispersed distribution of allelic genes as well as transposed copies.
Nucl. Acids. Res. 23, 1901-1911External link.

10. Fischer, A., Saedler, H. and Theissen, G. (1995).
Restriction fragment length polymorphism-coupled domain-directed differential display: a highly efficient technique for expression analysis of multigene families.
Proc. Natl. Acad. Sci. USA 92, 5331-5335External link.

9. Theißen, G., Strater, T., Fischer, A. and Saedler, H. (1995).
Structural characterization, chromosomal localization and phylogenetic evaluation of two pairs of AGAMOUS-like MADS-box genes from maize.
Gene 156, 155-166External link.

8. Theißen, G., Schönborn, J. and Wagner, R. (1993).
Temperature-gradient gel electrophoresis for the detection and characterization of curved DNA-fragments.
Nucl. Acids Res. 21, 4643-4644External link.

7. Theißen, G., Thelen, L. and Wagner, R. (1993).
Some base substitutions in the leader of an E. coli ribosomal RNA operon affect the structure and function of ribosomes - evidence for a transient scaffold function of the rRNA leader.
J. Mol. Biol. 233, 203-218.

6. Zacharias, M., Theissen, G., Bradaczek, C. and Wagner, R. (1991).
Analysis of sequence elements important for the synthesis and control of ribosomal RNA in E. coli.
Biochimie 73, 699-712.

5. Theissen, G., Pardon, B. and Wagner, R. (1990).
A quantitative assessment for transcriptional pausing of DNA-dependent RNA polymerases in vitro.
Anal. Biochem. 189, 254-261.

4. Theißen, G., Behrens, S.E. and Wagner, R. (1990).
Functional importance of the Escherichia coli ribosomal RNA leader box A sequence for post-transcriptional events.
Molec. Microbiol. 4, 1667-1678.

3. Theißen, G., Eberle, J., Zacharias, M., Tobias, L. and Wagner, R. (1990).
The tL structure within the leader region of Escherichia coli ribosomal RNA operons has post-transcriptional functions.
Nucl. Acids Res. 18, 3893-3901.

2. Klaff, P., Gruner, R., Hecker, R., Sättler, A., Theissen, G. and Riesner, D. (1989).
Reconstituted and cellular viroid-protein complexes.
J. gen. Virol. 70, 2257-2270.

1. Theissen, G., Richter, A. and Lukacs, N. (1989).
Degree of biotinylation in nucleic acids estimated by a gel retardation assay.
Anal. Biochem. 179, 98-105.