Levels of ordering in coding and noncoding regions of DNA sequences

1996 ◽  
Vol 222 (5) ◽  
pp. 354-360 ◽  
Author(s):  
V.R. Chechetkin ◽  
V.V. Lobzin
2017 ◽  
Vol 142 (6) ◽  
pp. 434-443
Author(s):  
Eun Ju Cheong ◽  
Myong-Suk Cho ◽  
Seung-Chul Kim ◽  
Chan-Soo Kim

Cultivated flowering cherries (Prunus subgenus Cerasus), which are one of the most popular ornamental trees around the world, have been developed through artificial hybridizations among wild flowering cherries. Among the hundreds of cultivars of flowering cherries, Prunus ×yedoensis ‘Somei-yoshino’ is the most common and widespread. However, its origin and genetic relationship to wild P. yedoensis, naturally occurring on Jeju Island, South Korea, have long been debated. We used sequence polymorphisms in eight chloroplast DNA (cpDNA) noncoding regions to distinguish wild and cultivated flowering cherries among 104 individuals (55 accessions). We were able to distinguish two distinct groups, one corresponding to wild P. yedoensis collections from Jeju Island and the other collections of cultivated P. ×yedoensis from Korea, Japan, and the United States. The chlorotype diversity of wild P. yedoensis in Jeju Island and cultivated P. ×yedoensis collections in the United States was quite high, suggesting multiple natural hybrid origins and long history of cultivation from different original sources, respectively.


Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 735-749
Author(s):  
Gerard Zurawski ◽  
Michael T Clegg ◽  
Anthony H D Brown

ABSTRACT Analysis of a 2175-base pair (bp) SmaI-HindIII fragment of barley chloroplast DNA revealed that rbcL (the gene for the large subunit of ribulose 1,5-bisphosphate carboxylase) and atpB (the gene for the β subunit of ATPase) are transcribed divergently and are separated by an untranscribed region of 155-166 bp. The rbcL mRNA has a 320-residue untranslated leader region, whereas the atpB mRNA has a 296- to 309-residue leader region. The sequence of these regions, together with the initial 113 bp of the atpB-coding region and the initial 1279 bp of the rbcL-coding region, is compared with the analogous maize chloroplast DNA sequences. Two classes of nucleotide differences are present, substitutions and insertions/deletions. Nucleotide substitutions show a 1.9-fold bias toward transitions in the rbcL-coding region and a 1.5-fold bias toward transitions in the noncoding region. The level of nucleotide substitutions between the barley and maize sequences is about 0.065/bp. Seventy-one percent of the substitutions in the rbcL-coding region are at the third codon position, and 95% of these are synonymous changes. Insertion/deletion events, which are confined to the noncoding regions, are not randomly distributed in these regions and are often associated with short repeated sequences. The extent of change for the noncoding regions (about 0.093 events/bp) is less than the extent of change at the third codon positions in the rbcL-coding region (about 0.135 events/bp), including insertion/delection events. Limited sequence analysis of the analogous DNA from a wild line (Hordeum spontaneum) and a primitive Iranian barley (H. vulgare) suggested a low rate of chloroplast DNA evolution. Compared to spinach chloroplast DNA, the barley rbcL-atpB untranslated region is extremely diverged, with only the putative rbcL promoters and ribosome-binding site being extensively conserved.


Fractals ◽  
1995 ◽  
Vol 03 (02) ◽  
pp. 269-284 ◽  
Author(s):  
S. HAVLIN ◽  
S.V. BULDYREV ◽  
A.L. GOLDBERGER ◽  
R.N. MANTEGNA ◽  
C.-K. PENG ◽  
...  

We present evidence supporting the idea that the DNA sequence in genes containing noncoding regions is correlated, and that the correlation is remarkably long range—indeed, base pairs thousands of base pairs distant are correlated. We do not find such a long-range correlation in the coding regions of the gene. We resolve the problem of the “non-stationarity” feature of the sequence of base pairs by applying a new algorithm called Detrended Fluctuation Analysis (DFA). We address the claim of Voss that there is no difference in the statistical properties of coding and noncoding regions of DNA by systematically applying the DFA algorithm, as well as standard FFT analysis, to all eukaryotic DNA sequences (33 301 coding and 29 453 noncoding) in the entire GenBank database. We describe a simple model to account for the presence of long-range power-law correlations which is based upon a generalization of the classic Lévy walk. Finally, we describe briefly some recent work showing that the noncoding sequences have certain statistical features in common with natural languages. Specifically, we adapt to DNA the Zipf approach to analyzing linguistic texts, and the Shannon approach to quantifying the “redundancy” of a linguistic text in terms of a measurable entropy function. We suggest that noncoding regions in plants and invertebrates may display a smaller entropy and larger redundancy than coding regions, further supporting the possibility that noncoding regions of DNA may carry biological information.


2016 ◽  
Vol 53 (2) ◽  
pp. 315-326
Author(s):  
Servet Martínez

Abstract Let I be a finite set and S be a nonempty strict subset of I which is partitioned into classes, and let C(s) be the class containing s ∈ S. Let (Ps: s ∈ S) be a family of distributions on IN, where each Ps applies to sequences starting with the symbol s. To this family, we associate a class of distributions P(π) on IN which depends on a probability vector π. Our main results assume that, for each s ∈ S, Ps regenerates with distribution Ps' when it encounters s' ∈ S ∖ C(s). From semiregenerative theory, we determine a simple condition on π for P(π) to be time stationary. We give a similar result for the following more complex model. Once a symbol s' ∈ S ∖ C(s) has been encountered, there is a decision to be made: either a new region of type C(s') governed by Ps' starts or the region continues to be a C(s) region. This decision is modeled as a random event and its probability depends on s and s'. The aim in studying these kinds of models is to attain a deeper statistical understanding of bacterial DNA sequences. Here I is the set of codons and the classes (C(s): s ∈ S) identify codons that initiate similar genomic regions. In particular, there are two classes corresponding to the start and stop codons which delimit coding and noncoding regions in bacterial DNA sequences. In addition, the random decision to continue the current region or begin a new region of a different class reflects the well-known fact that not every appearance of a start codon marks the beginning of a new coding region.


2011 ◽  
Vol 38 (2) ◽  
pp. 261-271 ◽  
Author(s):  
N. Crato ◽  
R. R. Linhares ◽  
S. R.C. Lopes

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Petra Krafčíková ◽  
Erika Demkovičová ◽  
Andrea Halaganová ◽  
Viktor Víglaský

The HIV virus is one of the most studied viruses in the world. This is especially true in terms of gene sequencing, and to date more than 9 thousand genomic sequences of HIV isolates have been sequenced and analyzed. In this study, a series of DNA sequences, which have the potential to form G-quadruplex structures, is analyzed. Several such sequences were found in various coding and noncoding virus domains, including the U3 LTR, tat, rev, env, and vpx regions. Interestingly, a homological sequence to the already well-known HIV integrase aptamer was identified in the minus-strand. The sequences derived from original isolates were analyzed using standard spectral and electrophoretic methods. In addition, a recently developed methodology is applied which uses induced circular dichroism spectral profiles of G-quadruplex-ligand (Thiazole Orange) complexes to determine if G-rich sequences can adopt G-quadruplex structure. Targeting the G-quadruplexes or peptide domains corresponding to the G-rich coding sequence in HIV offers researchers attractive therapeutic targets which would be of particular use in the development of novel antiviral therapies. The analysis of G-rich regions can provide researchers with a path to find specific targets which could be of interest for specific types of virus.


Author(s):  
David P. Bazett-Jones ◽  
Mark L. Brown

A multisubunit RNA polymerase enzyme is ultimately responsible for transcription initiation and elongation of RNA, but recognition of the proper start site by the enzyme is regulated by general, temporal and gene-specific trans-factors interacting at promoter and enhancer DNA sequences. To understand the molecular mechanisms which precisely regulate the transcription initiation event, it is crucial to elucidate the structure of the transcription factor/DNA complexes involved. Electron spectroscopic imaging (ESI) provides the opportunity to visualize individual DNA molecules. Enhancement of DNA contrast with ESI is accomplished by imaging with electrons that have interacted with inner shell electrons of phosphorus in the DNA backbone. Phosphorus detection at this intermediately high level of resolution (≈lnm) permits selective imaging of the DNA, to determine whether the protein factors compact, bend or wrap the DNA. Simultaneously, mass analysis and phosphorus content can be measured quantitatively, using adjacent DNA or tobacco mosaic virus (TMV) as mass and phosphorus standards. These two parameters provide stoichiometric information relating the ratios of protein:DNA content.


Author(s):  
Barbara Trask ◽  
Susan Allen ◽  
Anne Bergmann ◽  
Mari Christensen ◽  
Anne Fertitta ◽  
...  

Using fluorescence in situ hybridization (FISH), the positions of DNA sequences can be discretely marked with a fluorescent spot. The efficiency of marking DNA sequences of the size cloned in cosmids is 90-95%, and the fluorescent spots produced after FISH are ≈0.3 μm in diameter. Sites of two sequences can be distinguished using two-color FISH. Different reporter molecules, such as biotin or digoxigenin, are incorporated into DNA sequence probes by nick translation. These reporter molecules are labeled after hybridization with different fluorochromes, e.g., FITC and Texas Red. The development of dual band pass filters (Chromatechnology) allows these fluorochromes to be photographed simultaneously without registration shift.


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