A novel 2D graphical representation of DNA sequences and its application.

In this paper, we introduce a novel 2D graphical representation of DNA sequences, the W-curve, which is embedded in two unit circles. We associate the W-curves with the classifications of the nucleotides according to their chemical properties. Then we obtain an 8-component vector with entries being the average sums of the abscissa and y-axis of A+C and T+G (A+T and C+G, A+G and T+C), respectively. The introduced vector results in simpler characterizations and comparisons of DNA sequences. The construction of the W-curve has some important advantages: (1) it avoids loss of information and the W-curve standing for DNA doesn't overlap or intersect itself; (2) the space the W-curve occupied is very small, just two unit circles. The utility of the approach can be illustrated by the examination of similarities/dissimilarities among the coding sequences of the first exon of beta-globin gene of eleven different species in Table 1.