scholarly journals Nonrandom localization of recombination events in human alpha satellite repeat unit variants: implications for higher-order structural characteristics within centromeric heterochromatin.

1993 ◽  
Vol 13 (10) ◽  
pp. 6520-6529 ◽  
Author(s):  
P E Warburton ◽  
J S Waye ◽  
H F Willard
Keyword(s):  
Dna Sequences ◽  
Concerted Evolution ◽  
Repeat Unit ◽  
Higher Order ◽  
Centromeric Heterochromatin ◽  
Alpha Satellite ◽  
Repeated Dna ◽  
Satellite Repeat ◽  
Repeat Units ◽  
Tandemly Repeated Dna

Tandemly repeated DNA families appear to undergo concerted evolution, such that repeat units within a species have a higher degree of sequence similarity than repeat units from even closely related species. While intraspecies homogenization of repeat units can be explained satisfactorily by repeated rounds of genetic exchange processes such as unequal crossing over and/or gene conversion, the parameters controlling these processes remain largely unknown. Alpha satellite DNA is a noncoding tandemly repeated DNA family found at the centromeres of all human and primate chromosomes. We have used sequence analysis to investigate the molecular basis of 13 variant alpha satellite repeat units, allowing comparison of multiple independent recombination events in closely related DNA sequences. The distribution of these events within the 171-bp monomer is nonrandom and clusters in a distinct 20- to 25-bp region, suggesting possible effects of primary sequence and/or chromatin structure. The position of these recombination events may be associated with the location within the higher-order repeat unit of the binding site for the centromere-specific protein CENP-B. These studies have implications for the molecular nature of genetic recombination, mechanisms of concerted evolution, and higher-order structure of centromeric heterochromatin.

Nonrandom localization of recombination events in human alpha satellite repeat unit variants: implications for higher-order structural characteristics within centromeric heterochromatin

1993 ◽  
Vol 13 (10) ◽  
pp. 6520-6529
Author(s):  
P E Warburton ◽  
J S Waye ◽  
H F Willard
Keyword(s):  
Dna Sequences ◽  
Concerted Evolution ◽  
Repeat Unit ◽  
Higher Order ◽  
Centromeric Heterochromatin ◽  
Alpha Satellite ◽  
Repeated Dna ◽  
Satellite Repeat ◽  
Repeat Units ◽  
Tandemly Repeated Dna

Tandemly repeated DNA families appear to undergo concerted evolution, such that repeat units within a species have a higher degree of sequence similarity than repeat units from even closely related species. While intraspecies homogenization of repeat units can be explained satisfactorily by repeated rounds of genetic exchange processes such as unequal crossing over and/or gene conversion, the parameters controlling these processes remain largely unknown. Alpha satellite DNA is a noncoding tandemly repeated DNA family found at the centromeres of all human and primate chromosomes. We have used sequence analysis to investigate the molecular basis of 13 variant alpha satellite repeat units, allowing comparison of multiple independent recombination events in closely related DNA sequences. The distribution of these events within the 171-bp monomer is nonrandom and clusters in a distinct 20- to 25-bp region, suggesting possible effects of primary sequence and/or chromatin structure. The position of these recombination events may be associated with the location within the higher-order repeat unit of the binding site for the centromere-specific protein CENP-B. These studies have implications for the molecular nature of genetic recombination, mechanisms of concerted evolution, and higher-order structure of centromeric heterochromatin.

Genomic organization of alpha satellite DNA on human chromosome 7: evidence for two distinct alphoid domains on a single chromosome

1987 ◽  
Vol 7 (1) ◽  
pp. 349-356
Author(s):  
J S Waye ◽  
S B England ◽  
H F Willard
Keyword(s):  
Human Genome ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Repeat Unit ◽  
Higher Order ◽  
Chromosome 7 ◽  
Alpha Satellite ◽  
Single Chromosome ◽  
Alpha Satellite Dna ◽  
Repeat Structure

A complete understanding of chromosomal disjunction during mitosis and meiosis in complex genomes such as the human genome awaits detailed characterization of both the molecular structure and genetic behavior of the centromeric regions of chromosomes. Such analyses in turn require knowledge of the organization and nature of DNA sequences associated with centromeres. The most prominent class of centromeric DNA sequences in the human genome is the alpha satellite family of tandemly repeated DNA, which is organized as distinct chromosomal subsets. Each subset is characterized by a particular multimeric higher-order repeat unit consisting of tandemly reiterated, diverged alpha satellite monomers of approximately 171 base pairs. The higher-order repeat units are themselves tandemly reiterated and represent the most recently amplified or fixed alphoid sequences. We present evidence that there are at least two independent domains of alpha satellite DNA on chromosome 7, each characterized by their own distinct higher-order repeat structure. We determined the complete nucleotide sequences of a 6-monomer higher-order repeat unit, which is present in approximately 500 copies per chromosome 7, as well as those of a less-abundant (approximately 10 copies) 16-monomer higher-order repeat unit. Sequence analysis indicated that these repeats are evolutionarily distinct. Genomic hybridization experiments established that each is maintained in relatively homogeneous tandem arrays with no detectable interspersion. We propose mechanisms by which multiple unrelated higher-order repeat domains may be formed and maintained within a single chromosomal subset.

scholarly journals Genomic organization of alpha satellite DNA on human chromosome 7: evidence for two distinct alphoid domains on a single chromosome.

1987 ◽  
Vol 7 (1) ◽  
pp. 349-356 ◽  
Author(s):  
J S Waye ◽  
S B England ◽  
H F Willard
Keyword(s):  
Human Genome ◽  
Dna Sequences ◽  
Satellite Dna ◽  
Repeat Unit ◽  
Higher Order ◽  
Chromosome 7 ◽  
Alpha Satellite ◽  
Single Chromosome ◽  
Alpha Satellite Dna ◽  
Repeat Structure

A complete understanding of chromosomal disjunction during mitosis and meiosis in complex genomes such as the human genome awaits detailed characterization of both the molecular structure and genetic behavior of the centromeric regions of chromosomes. Such analyses in turn require knowledge of the organization and nature of DNA sequences associated with centromeres. The most prominent class of centromeric DNA sequences in the human genome is the alpha satellite family of tandemly repeated DNA, which is organized as distinct chromosomal subsets. Each subset is characterized by a particular multimeric higher-order repeat unit consisting of tandemly reiterated, diverged alpha satellite monomers of approximately 171 base pairs. The higher-order repeat units are themselves tandemly reiterated and represent the most recently amplified or fixed alphoid sequences. We present evidence that there are at least two independent domains of alpha satellite DNA on chromosome 7, each characterized by their own distinct higher-order repeat structure. We determined the complete nucleotide sequences of a 6-monomer higher-order repeat unit, which is present in approximately 500 copies per chromosome 7, as well as those of a less-abundant (approximately 10 copies) 16-monomer higher-order repeat unit. Sequence analysis indicated that these repeats are evolutionarily distinct. Genomic hybridization experiments established that each is maintained in relatively homogeneous tandem arrays with no detectable interspersion. We propose mechanisms by which multiple unrelated higher-order repeat domains may be formed and maintained within a single chromosomal subset.

scholarly journals A Mutation of the Yeast Gene Encoding PCNA Destabilizes Both Microsatellite and Minisatellite DNA Sequences

Genetics ◽  
1999 ◽  
Vol 151 (2) ◽  
pp. 511-519 ◽  
Author(s):  
Robert J Kokoska ◽  
Lela Stefanovic ◽  
Andrew B Buermeyer ◽  
R Michael Liskay ◽  
Thomas D Petes
Keyword(s):  
Dna Polymerase ◽  
Repetitive Dna ◽  
Dna Sequences ◽  
Repeat Unit ◽  
Nuclear Antigen ◽  
Temperature Sensitive ◽  
Dinucleotide Repeats ◽  
Yeast Saccharomyces Cerevisiae ◽  
Dna Polymerase Δ ◽  
Repeat Units

AbstractThe POL30 gene of the yeast Saccharomyces cerevisiae encodes the proliferating cell nuclear antigen (PCNA), a protein required for processive DNA synthesis by DNA polymerase δ and ϵ. We examined the effects of the pol30-52 mutation on the stability of microsatellite (1- to 8-bp repeat units) and minisatellite (20-bp repeat units) DNA sequences. It had previously been shown that this mutation destabilizes dinucleotide repeats 150-fold and that this effect is primarily due to defects in DNA mismatch repair. From our analysis of the effects of pol30-52 on classes of repetitive DNA with longer repeat unit lengths, we conclude that this mutation may also elevate the rate of DNA polymerase slippage. The effect of pol30-52 on tracts of repetitive DNA with large repeat unit lengths was similar, but not identical, to that observed previously for pol3-t, a temperature-sensitive mutation affecting DNA polymerase δ. Strains with both pol30-52 and pol3-t mutations grew extremely slowly and had minisatellite mutation rates considerably greater than those observed in either single mutant strain.

Distribution of a Secale cereale DNA repeat sequence among 25 Hordeum species

Genome ◽  
1989 ◽  
Vol 32 (3) ◽  
pp. 383-388 ◽  
Author(s):  
P. K. Gupta ◽  
G. Fedak ◽  
S. J. Molnar ◽  
Roger Wheatcroft
Keyword(s):  
Dna Sequences ◽  
Secale Cereale ◽  
Dna Hybridization ◽  
Interspecific Variation ◽  
Repeat Sequence ◽  
Species Variation ◽  
Repeated Dna ◽  
Repeat Units ◽  
Dna Repeat ◽  
Hordeum Species

DNA of 61 accessions representing 25 Hordeum species was tested for homology to a highly repeated 120-bp sequence from Secale cereale (rye). Homology to the probe (pSC119) was detected in dot blots of all species except H. vulgare (cultivated barley) and its related species, H. agriocrithon and H. spontaneum. Hybridization patterns of Southern blots of restriction fragments demonstrated both intraspecific and interspecific variation in the organization of complex units of DNA having homology to the probe. For eight species, digestion of the DNA with BamHI gave ladder patterns characteristic of tandem arrays of 120-bp repeat units. For EcoRI, HindIII, and SacI digests, the hybridization patterns appeared to be highly conserved in the section Hordeum, except those for H. bulbosum, which were unique. A further set of patterns for these three enzymes was common among the remaining species of the genus. Thus, DNA hybridization with pSC119 generally gave patterns consistent with the current taxonomy of Hordeum species, except that H. bulbosum and H. vulgare were not shown to be closely related.Key words: Hordeum, repeated DNA sequences, pSC119, species variation.

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