Rapidly varying DNA sequences in flax

Cullis, Christopher A.; Cleary, W. G.

doi:10.1139/g86-035

Cited by 58 publications

(18 citation statements)

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“…The hybridization pattern of the tri-generic hybrid and of the six regenerants, which differed from that of regenerant N16, confirms this point of view. A similar effect of in vitro cultivation on the structural organization of plant genomes has been described earlier ( WALBOT and CULLIS 1985;CULLIS and CLEARY 1986;ZHENG et al 1987;MOORE et al 1988). A 75-fold increase in the copy number of a repetitive sequence was discovered in rice culture (ZHENG et al 1987), and local amplification of rye repetitive sequences was observed on the short arm of chromosome 7R of wheat-rye hybrids and their progenitors ( LAPITAN et al 1988).…”

Section: Discussionsupporting

confidence: 74%

Molecular Analysis of the Genomes of Wide Hybrids in Cereals

Svitashev¹,

Вершинин²,

Trunova³

et al. 2004

Hereditas

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The structural organization of various highly repetitive DNA sequences from barley (H. vulgare) and rye (S. cereale) were studied by blot‐hybridization in hybrids of Hordeum × Secale, the tri‐generic hybrid H. vulgare × T. timopheevii × S. cereale, and regenerants of the tri‐generic hybrid after in vitro cultivation. The set of repetitive DNA sequences used proved to be valuable as molecular markers for the analysis of the hybrid genetic material. Use of the probes permitted the identification of each generation during wide crossing and following backcrosses. Structural rearrangements of certain repetitive sequences were revealed, which were probably generated by such stress factors as wide crosses and in vitro cultivation. New RFLP patterns, not found in the parental species, arose on two occasions, once in a backcross of the hybrid H. geniculatum × S. cereale, once in a regenerant of the tri‐generic hybrid. When the hybrid H. genicula‐tum × S. cereale was backcrossed to S. cereale, new hybridization fragments, characteristic of the wild barley species H. jubatum were discovered. Changes in the structural organization of several repetitive sequences are described, while the non‐random nature of these rearrangements is discussed.

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Section: Discussionsupporting

confidence: 74%

Molecular Analysis of the Genomes of Wide Hybrids in Cereals

Svitashev¹,

Вершинин²,

Trunova³

et al. 2004

Hereditas

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“…Also in the light of the finding that the genome size of European accessions differs significantly from that of African accessions, it seems proposable that quantitative changes in the nuclear genome of V. faba play some role in environmental adaptation. Also in other species, this biological role is strongly suggested by the existence of correlations with such environmental factors as latitude or altitude (see Cavallini & Natali, 1991), temperature (as in F. arundinacea; Ceccarelli et a!., 1992) or substratum composition (as in flax; see Cullis & Cleary, 1986).…”

Section: Discussionmentioning

confidence: 99%

Genome size variation in Vicia faba

Ceccarelli

Maggini

1995

Heredity

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Findings obtained using different approaches indicated the occurrence of genomic size variations within V. faba. Significant differences in the basic amount of nuclear DNA (up to 34.6 per cent) between 39 local populations collected from the Mediterranean Basin were observed by means of Feulgen/DNA cytophotometry. By contrast, no difference in genome size was found when five commercial varieties were compared. Dot blot hybridization of FokI V. faba repeats to genomic DNAs showed up to fourfold differences in the redundancy of these sequences in the nuclear DNA of different accessions. In agreement with the cytophotometric findings, a significant, positive correlation was determined between the DNA contents of populations and the copy numbers of DNA sequences related to FokI repeats. Significant differences between accessions were found in the length of the chromosome complement at metaphase, and these differences were particularly apparent in certain chromosome pairs. A positive correlation was found between the length of the complement and the genome size of the populations. These results are discussed in relation to other data in the literature on intraspecific nuclear DNA changes.Keywords: DNA cytophotometry, FokI DNA sequences, intraspecific DNA changes, karyometry, repetitive DNA, V/cia faba. tntroduction Today, there is a growing consensus of opinion that proliferation or deletion of nuclear DNA sequences does not occur only in the case of divergence and evolution of species. Indeed, many results obtained in different materials have shown that fluid domains, which are capable of rapid quantitative changes, may exist in the genome. These DNA domains, which are generally made up of repeated sequences, possibly occur more commonly, and express their ability to vary more frequently, in plant genomes than in animal genomes (reviewed for plants by Walbot & Cullis, 1985;Cionini, 1989; Bassi, 1990; Cullis, 1990; NagI, 1990).Redundancy variation of DNA sequences may accompany certain developmental processes. It has been suggested that they play a regulatory role in development (Frediani et a!., 1994 and references Because they may be of great biological importance and since many of their aspects are poorly understood, the above-mentioned genomic changes deserve thorough investigation. These changes have been shown to occur in many plant species (see Cavallini & Natali, 1991 show redundancy variations in Helianthus annuus (Natali et al., 1993), while quantitative differences in the nuclear DNA between populations of hexaploid Festuca arundinacea are mainly the result of changes in a fraction of highly repeated sequences (Ceccarelli et a!., 1992). The chromosomal organization of varying DNA sequences, as well as the mechanism by which intraspecific alterations in genome size and organization are produced and controlled, are almost entirely unknown.We investigated the nuclear DNA changes in Vicia faba by studying a number of local populationscollected from the Mediterranean Basin. Results are reported of DNA cytophot...

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“…The somatic chromosomal rearrangements have been proposed to be due to transposable element activity (19). The The number of rDNA repeats in T. officinale has been estimated to be about several thousand copies per haploid genome (8) (22), and possibly in wheat (23), and gene amplification is thought to be involved in the somatic induction of =2-fold variation in rDNA and other repeated sequence DNA in flax (20). Other studies also suggest that non-Mendelian mechanisms may influence rDNA recombination and variation, although the mechanisms causing this variation are not known.…”

Section: Resultsmentioning

confidence: 99%

Genotypic variation within asexual lineages of Taraxacum officinale.

King

Schaal

1990

Proc. Natl. Acad. Sci. U.S.A.

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Restriction site variation in DNA that encodes rRNA (rDNA) was surveyed among 714 offspring within 31 lineages (26 genotypes) of obligate asexually reproducing Taraxacum officinale (dandelions). Although clonal offspring are expected, plants with nonparental rDNA were produced from two parents that were themselves siblings (same genotype). The variation is best characterized by the loss of an EcoRI restriction site that maps to the spacer region in the parental rDNA and is most likely involved in amplification of rare or unique rDNA repeats. In one family, 41 surveyed offspring lacked the EcoRI site. In the other family, only 1 of 26 offspring lost the EcoRI site. Other classes of DNA surveyed, chloroplast DNA and the alcohol dehydrogenase 2 gene (Adh2), showed no variation. However, offspring with nonparental rDNA also had nonparental alcohol dehydrogenase 1 (Adhl) restriction fragments. Because somatic mutations in plants can be incorporated into reproductive tissue, we propose that somatic events affecting at least both multicopy rDNA and DNA homologous to the maize Adhi gene occurred at different developmental times in the two families. An event early in development would result in all variant offspring; an event late in development would result in a single variant offspring. These results support the view that mutation (in the broad sense) influences the level of genotypic variation in asexual organisms, which may facilitate adaptive evolution of asexual species.Sexual reproduction and recombination creates genotypic variation, which is necessary for the evolution of populations and species. Asexual

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Rapidly varying DNA sequences in flax

Cited by 58 publications

References 0 publications

Molecular Analysis of the Genomes of Wide Hybrids in Cereals

Molecular Analysis of the Genomes of Wide Hybrids in Cereals

Genome size variation in Vicia faba

Genotypic variation within asexual lineages of Taraxacum officinale.

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