The growing number of completely sequenced organisms offers the opportunity to systematically investigate as a whole their predicted ORF products and their codons as well as their amino-acid content. In genome explorations it is of interest to identify organisms or parts of their ORF products that are characterized by some preferred amino-acids or codons. These investigations generally involve large and complex datasets. In this work, using this method we present a systematic analysis of all available completely sequenced organisms and their comparisons according to their amino-acid and codon compositions. A brief description of the method is presented here, detailed explanations with worked examples can be found in Benzecri 1973 and in Greenacre 1984.
Correspondence analysis is a multivariate method that applies for positive numerical data tables.
The factors are constructed according to the information they represent and therefore are presented in a decreasing order of importance. A maximum of n-1 such factors can be determined, where n is the lowest of the 2 numbers of observations and of variables. All of these can be seen in the following Figure obtained by correspondence analysis. It can be seen that organisms are plotted near the bases where they have high values. This simple example shows how information included in a given data table can be synthesized on a graph in a very efficient way.