Molecular and cytological characterization of a highly repeated DNA sequence in Raphanus sativus

A highly repeated DNA sequence with a repeat unit of ca. 180 bp was found in genomic DNA HindIII-digests of Raphanus sativus. The repeating units of six isolated, independent clones were sequenced. These units have 177 or 178 bp, are 36% G+C in their DNA base composition, and show 90% sequence homology. The copy number of this 180-bp repeat unit is about 0.5 × 106 per diploid genome. In situ hybridization analysis with the repeating unit as the probe and C-banding analysis indicated that the repeated DNA sequence of R. sativus is closely associated with the major C-heterochromatins in the proximal regions of all 18 chromosomes at mitotic metaphase.Key words: Raphanus sativus, repeated DNA sequence, nucleotide sequence, in situ hybridization, C-banding.

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Organization and distribution of a Sau3A tandem repeated DNA sequence in Picea (Pinaceae) species

Genome ◽

10.1139/g98-054 ◽

1998 ◽

Vol 41 (4) ◽

pp. 560-565 ◽

Cited By ~ 12

Author(s):

Garth R Brown ◽

Craig H Newton ◽

John E Carlson

Keyword(s):

In Situ Hybridization ◽

Dna Sequence ◽

Picea Glauca ◽

Tandem Repeats ◽

Picea Sitchensis ◽

Repeated Dna ◽

Metaphase Chromosomes ◽

Genes Encoding ◽

Repeated Dna Sequence

Repeated DNA families contribute to the large genomes of coniferous trees but are poorly characterized. We report the analysis of a 142 bp tandem repeated DNA sequence identified by the restriction enzyme Sau3A and found in approximately 20 000 copies in Picea glauca. Southern hybridization indicated that the repeated DNA family is specific to the genus, was amplified early in its evolution, and has undergone little structural alteration over evolutionary time. Fluorescence in situ hybridization localized arrays of the Sau3A repeating element to the centromeric regions of different subsets of the metaphase chromosomes of P. glauca and the closely related Picea sitchensis, suggesting that mechanisms leading to the intragenomic movement of arrays may be more active than those leading to mutation of the repeating elements themselves. Unambiguous identification of P. glauca and P. sitchensis chromosomes was made possible by co-localizing the Sau3A tandem repeats and the genes encoding the 5S and 18S-5.8S-26S ribosomal RNAs.Key words: Picea, repeated DNA, in situ hybridization, centromere.

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A highly repeated DNA sequence in Arabidopsis thaliana

MGG Molecular & General Genetics ◽

10.1007/bf00331018 ◽

1986 ◽

Vol 204 (3) ◽

pp. 417-423 ◽

Cited By ~ 169

Author(s):

Jose M. Martinez-Zapater ◽

Mark A. Estelle ◽

Chris R. Somerville

Keyword(s):

Arabidopsis Thaliana ◽

Dna Sequence ◽

Repeated Dna ◽

Highly Repeated Dna ◽

Repeated Dna Sequence

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Organization ofPlasmodium falciparum genome: 1. Evidence for a highly repeated DNA sequence

Nucleic Acids Research ◽

10.1093/nar/13.6.1965 ◽

1985 ◽

Vol 13 (6) ◽

pp. 1965-1975 ◽

Cited By ~ 10

Author(s):

Ramareddy V. Guntaka ◽

Siddarame Gowda ◽

Arepalli S. Rao ◽

Theodore J. Green

Keyword(s):

Dna Sequence ◽

Falciparum Genome ◽

Repeated Dna ◽

Highly Repeated Dna ◽

Ofplasmodium Falciparum ◽

Repeated Dna Sequence

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Chromosomal distribution of a repeated DNA sequence from C-genome heterochromatin and the identification of a new ribosomal DNA locus in the Avena genus

Genome ◽

10.1139/g95-071 ◽

1995 ◽

Vol 38 (3) ◽

pp. 548-557 ◽

Cited By ~ 39

Author(s):

Araceli Fominaya ◽

Gregorio Hueros ◽

Yolanda Loarce ◽

Esther Ferrer

Keyword(s):

In Situ Hybridization ◽

Satellite Dna ◽

Repeated Dna ◽

Chromosomal Distribution ◽

Genome Chromosome ◽

26S Rdna ◽

A Genome ◽

C Genome ◽

Repeated Dna Sequence

Satellite DNA specific to the oat C genome was sequenced and located on chromosomes of diploid, tetraploid, and hexaploid Avena ssp. using in situ hybridization. The sequence was present on all seven C genome chromosome pairs and hybridized to the entire length of each chromosome, with the exception of the terminal segments of some chromosome pairs. Three chromosome pairs belonging to the A genome showed hybridization signals near the telomeres of their long arms. The existence of intergenomic chromosome rearrangements and the deletions of the repeated units are deduced from these observations. The number of rDNA loci (18S–5.8S–26S rDNA) was determined for the tetraploid and hexaploid oat species. Simultaneous in situ hybridization with the satellite and rDNA probes was used to assign the SAT chromosomes of these species to their correct genomes.Key words: oats, satellite DNA, rDNA, in situ hybridization, genome evolution.

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