Format

Send to

Choose Destination
Gene. 2004 May 26;333:143-9.

Cytosine methylation and CpG, TpG (CpA) and TpA frequencies.

Author information

1
Laboratoire de Génétique Moléculaire, Institut Jacques Monod, 2 Place Jussieu, F-75005 Paris, France.

Abstract

An analysis of dinucleotide frequencies was carried out on DNAs from insects and mammals, as well as on large DNA sequences from the genomes of Drosophila melanogaster, Anopheles gambiae, puffer fish (Takifugu rubripes), zebra fish (Danio rerio) and human. These organisms were chosen because Drosophila and Anopheles DNAs have an extremely low level of methylation, human DNA a high level and fish DNA a two-fold higher level compared to human. The results indicate that: (i) CpG deficiency and the corresponding TpG (CpA) excess show no correlation with the level of DNA methylation; indeed, genomes endowed with strikingly different levels of DNA methylation (such as those of Drosophila and human) exhibited similar TpG (CpA) levels; (ii) the correlation between GC levels of large (50 kb) DNA sequences and TpA or CpG shortage levels do not appear to be due to CpG methylation followed by deamination; (iii) CpG dinucleotides are more frequent in fishes than in mammals; interestingly, the monotreme Ornitorhinchus anatinus shows an intermediate CpG frequency. The implications of these results are discussed.

PMID:
15177689
DOI:
10.1016/j.gene.2004.02.043
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center