Effect of replication on the third base of codons

We have analyzed third position in codons and have observed strong long-range correlations along DNA sequence. We have shown that the correlations are caused mostly by asymmetric replication. In the analysis, we have used a DNA walk (spider analysis Cebrat et al., Microbial Comparative Genomics 2(4) (1997) 259–268) in two-dimensional space [A–T,G–C]. The particular case of the E.coli sequence has been studied in detail.