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Comparative analysis using K-mer and K-flank patterns provides evidence for CpG island sequence evolution in mammalian genomes.

Chae H, Park J, Lee SW, Nephew KP, Kim S - Nucleic Acids Res. (2013)

Bottom Line: First, by calculating genome distance based on rank correlation tests, we show that k-mer and k-flank patterns around CpG sites can be used to correctly reconstruct the phylogeny of 10 mammalian genomes.Further, we used various machine learning algorithms to demonstrate that CpG islands sequences can be characterized using k-mers.In addition, by testing a human model on the nine different mammalian genomes, we provide the first evidence that k-mer signatures are consistent with evolutionary history.

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science, School of Informatics and Computing, Indiana University, Bloomington, IN, USA.

ABSTRACT
CpG islands are GC-rich regions often located in the 5' end of genes and normally protected from cytosine methylation in mammals. The important role of CpG islands in gene transcription strongly suggests evolutionary conservation in the mammalian genome. However, as CpG dinucleotides are over-represented in CpG islands, comparative CpG island analysis using conventional sequence analysis techniques remains a major challenge in the epigenetics field. In this study, we conducted a comparative analysis of all CpG island sequences in 10 mammalian genomes. As sequence similarity methods and character composition techniques such as information theory are particularly difficult to conduct, we used exact patterns in CpG island sequences and single character discrepancies to identify differences in CpG island sequences. First, by calculating genome distance based on rank correlation tests, we show that k-mer and k-flank patterns around CpG sites can be used to correctly reconstruct the phylogeny of 10 mammalian genomes. Further, we used various machine learning algorithms to demonstrate that CpG islands sequences can be characterized using k-mers. In addition, by testing a human model on the nine different mammalian genomes, we provide the first evidence that k-mer signatures are consistent with evolutionary history.

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Phylogenetic tree using top ranked 64 3-mers.
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gkt144-F3: Phylogenetic tree using top ranked 64 3-mers.

Mentions: Using the Newick format data, we used the on-line phylogeny drawing tool, called PHY-FI (25). A phylogenetic tree using top ranked 64 3-mers is shown in Figure 3, which is consistent with the evolutionary history of the 10 mammalian genomes. Additional results using different k-mers and k-flanks are available at http://biohealth.snu.ac.kr/wiki/index.php/PhylogeneticTreeFigure 3.


Comparative analysis using K-mer and K-flank patterns provides evidence for CpG island sequence evolution in mammalian genomes.

Chae H, Park J, Lee SW, Nephew KP, Kim S - Nucleic Acids Res. (2013)

Phylogenetic tree using top ranked 64 3-mers.
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3643570&req=5

gkt144-F3: Phylogenetic tree using top ranked 64 3-mers.
Mentions: Using the Newick format data, we used the on-line phylogeny drawing tool, called PHY-FI (25). A phylogenetic tree using top ranked 64 3-mers is shown in Figure 3, which is consistent with the evolutionary history of the 10 mammalian genomes. Additional results using different k-mers and k-flanks are available at http://biohealth.snu.ac.kr/wiki/index.php/PhylogeneticTreeFigure 3.

Bottom Line: First, by calculating genome distance based on rank correlation tests, we show that k-mer and k-flank patterns around CpG sites can be used to correctly reconstruct the phylogeny of 10 mammalian genomes.Further, we used various machine learning algorithms to demonstrate that CpG islands sequences can be characterized using k-mers.In addition, by testing a human model on the nine different mammalian genomes, we provide the first evidence that k-mer signatures are consistent with evolutionary history.

View Article: PubMed Central - PubMed

Affiliation: Department of Computer Science, School of Informatics and Computing, Indiana University, Bloomington, IN, USA.

ABSTRACT
CpG islands are GC-rich regions often located in the 5' end of genes and normally protected from cytosine methylation in mammals. The important role of CpG islands in gene transcription strongly suggests evolutionary conservation in the mammalian genome. However, as CpG dinucleotides are over-represented in CpG islands, comparative CpG island analysis using conventional sequence analysis techniques remains a major challenge in the epigenetics field. In this study, we conducted a comparative analysis of all CpG island sequences in 10 mammalian genomes. As sequence similarity methods and character composition techniques such as information theory are particularly difficult to conduct, we used exact patterns in CpG island sequences and single character discrepancies to identify differences in CpG island sequences. First, by calculating genome distance based on rank correlation tests, we show that k-mer and k-flank patterns around CpG sites can be used to correctly reconstruct the phylogeny of 10 mammalian genomes. Further, we used various machine learning algorithms to demonstrate that CpG islands sequences can be characterized using k-mers. In addition, by testing a human model on the nine different mammalian genomes, we provide the first evidence that k-mer signatures are consistent with evolutionary history.

Show MeSH