Abstract
TheNor-loci of polyploid wheats and their putative diploid progenitor species were assayed by probing isolated nuclear DNA with ribosomal DNA spacer sequences (spacer rDNA sequences, isolated by cloning), from theNor-loci of genomes B (Triticum aestivum), G (T. timopheevi), B (syn. S,T. speltoides), A (T. monococcum) and V (Dasypyrum villosum). DNA samples for analysis were digested with the restriction endonuclease Taq 1 and assayed by DNA-DNA hybridization under standard (37°C) and high stringency (64°C) conditions. The assay procedure emphasized differences between the divergent spacer sequences of the polyploid species and allowed relative homologies to the respective sequences in diploid species to be established. — The studies indicated thatT. timopheevi andT. speltoides contain different sets of spacer rDNA sequences which were readily distinguishable and, in the case ofT. timopheevi, assigned toNor-loci on different chromosomes. This contrast with the spacer rDNA sequences of the majorNor-loci on chromosomes 1 B and 6 B inT. aestivum, which were difficult to distinguish and were deduced to contain very similar sequences. Among the diploid progenitor species only the spacer rDNA fromT. speltoides shared close homology with polyploid wheat species. OneNor-locus inT. timopheevi (on chromosome 6 G) did not show close homology with any of the rDNA spacer probes available. — The data suggestsT. speltoides was the origin of someNor-loci for both theT. timopheevi andT. turgidum lines of tetraploid wheats. The possibility that the 6GNor-locus inT. timopheevi may have derived from an unknown diploid species by introgressive hybridization is discussed. The spacer rDNA sequence probe fromT. monococcum shared good homology with some accessions ofD. villosum and a line ofT. dicoccoides; the implications of this finding for evolution of present-day wheats are discussed.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Appels, R., Dvorak, J., 1982a: The wheat ribosomal DNA spacer region: Its structure and variation in populations and among species. — Theor. Appl. Genet.63: 337–348.
—, —, 1982b: Relative rates of divergence of spacer and gene sequence within the rDNA region of species in theTriticeae: implications for the maintenance of homogeneity of a repeated gene family. — Theor. Appl. Genet.63: 361–365.
—,Moran, L. B., 1984: Molecular analysis of alien chromatin introduced into wheat. — Stadler Genet. Symp.16: 529–557.
Appels, R., Gerlach, W. L., Dennis, E. S., Swift, H., Peacock, W. J., 1980: Molecular and chromosomal organisation of DNA sequences coding for the ribosomal RNAs in cereals. — Chromosoma78: 293–311.
—,McIntyre, C. L., Clarke, B. C., May, C. E., 1986: Alien chromatin in wheat: rDNA-spacer probes for detecting specificNor-loci introduced into wheat. — Canad. J. Genet. Cytol.28: 665–672.
Arnheim, N., 1983: Concerted evolution in multigenes. — InKoehn, R., Nei, M., (Eds.): Evolution of genes and proteins, pp. 38–61. — Sunderland, Mass.: Sinauer Associates Inc.
Badaeva, E. D., Shkutina, F. M., Bogdevich, I. N., Badaev, N. S., 1986: Comparative study ofTriticum aestivum andT. timopheevi genomes using C-banding technique. — Pl. Syst. Evol.154: 183–194.
Dhaliwal, H. S., Johnson, B. L., 1982: Diploidization and chromosome pairing affinities in the tetraploid wheats and their putative amphiploid progenitor. — Theor. Appl. Genet.61: 117–123.
Dvorak, J., Appels, R., 1982: Chromosome and nucleotide sequence differentiation in genomes of polyploidTriticum species. — Theoret. Appl. Genet.63: 349–360.
—,Lassner, M. W., Kota, R. S., Chen, K. C., 1984: The distribution of the ribosomal genes in theTriticum speltoides andElytrigia elongata genomes. — Canad. J. Genet. Cytol.26: 628–632.
Endo, T. R., 1985: The types of gametocidal chromosomes ofAegilops sharonensis andAe. longissima. — Japan J. Genet.60: 125–135.
Feldman, M., 1966: Identification of unpaired chromosomes in F 1 hybrids involvingTriticum aestivum andT. timopheevi. — Canad. J. Genet. Cytol.8: 144–151.
Friebe, B., Cermeno, M. C., Zeller, F. J., 1987: C-banding polymorphism and the analysis of nucleolar activity inDasypyrum villosum (L.)Candargy, its added chromosomes to hexaploid wheat and the amphiploidTriticum dicoccum-D. villosum. — Theoret. Appl. Genet.73: 337–342.
Gerlach, W. L., Bedbrook, J. R., 1979: Cloning and characterisation of ribosomal RNA genes from wheat and barley. — Nucleic Acids Res.7: 1869–1885.
Gill, B. S., Chen, P. D., 1987: Role of cytoplasm-specificity in the evolution of polyploid wheats. — Proc. Natl. Acad. Sci. U.S.A.84: 6800–6804.
Hart, G. E., 1984: Biochemical loci of hexaploid wheat. — InO'Brien, S. J., (Ed.): Genetic maps, pp. 485–490. — Cold Spring Harbor, New York: Cold Spring Harbor Laboratories.
Lassner, M., Anderson, O., Dvorak, J., 1987: Inferences on intergenomic homogenisation based on the molecular structure of a cloned ribosomal RNA gene from the Dgenome of bread wheat. — Genome29: 770–781.
Maan, S. S., 1975: Cytoplasmic variability and speciation inTriticinae. — InWali, M. K., (Ed.): Prairie: A multiple view, pp. 255–281. — Grand Forks: University of North Dakota Press.
McIntyre, C. L., Clarke, B. C., Appels, R., 1988a: Amplification and dispersion of repeated DNA sequences in theTriticeae. — Pl. Syst. Evol.160: 39–59.
—, —, —, 1988b: DNA sequence analyses of the ribosomal DNA spacer regions in theTriticeae. — Pl. Syst. Evol.160: 91–104.
Miller, T. E., Gerlach, W. L., Flavell, R. B., 1980: Nucleolus organizer variation in wheat and rye revealed by in situ hybridization. — Heredity45: 377–382.
—,Hutchinson, J., Reader, S. M., 1983: The identification of the nucleolus organiser chromosomes of diploid wheat. — Theor. Appl. Genet.65: 145–147.
Riley, R., Unrau, J., Chapman, V., 1958: Evidence on the origin of the B genome of wheat. — J. Heredity49: 91–98.
Sarkar, P., Stebbins, G. L., 1956: Morphological evidence concerning the origin of the B genome in wheat. — Amer. J. Bot.43: 297–304.
Scoles, G. J., Gill, B. S., Xin, Z.-Y., Clarke, B. C., McIntyre, C. L., Chapman, C., Appels, R., 1988: Frequent duplication and deletion events in the 5 S RNA genes and the associated spacer regions of theTriticeae. — Pl. Syst. Evol.160: 105–122.
Sears, E. R., 1953: Addition of the genome ofHaynaldia villosa toTriticum aestivum. — Amer. J. Bot.40: 168–173.
Tsujimoto, H., Tsunewaki, K., 1985: Hybrid dysgenesis in common wheat caused by gametocidal genes. — Japan. J. Genet.60: 565–578.
Tsunewaki, K., Ogihara, Y., 1983: The molecular basis of genetic diversity among cytoplasms ofTriticum andAegilops species. II. — Genetics104: 155–171.
Wagenaar, E. B., 1961: Studies on the genome ofTriticum timopheevi Zhuk. I. Evidence for genetic control of meiotic irregularities in tetraploid hybrids. — Canad. J. Genet. Cytol.3: 47–60.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Gill, B.S., Appels, R. Relationships betweenNor-loci from differentTriticeae species. Pl Syst Evol 160, 77–89 (1988). https://doi.org/10.1007/BF00936711
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF00936711