EN
Coding properties of yeast chromosomes were analysed and a strong asymmetry was found in nucleotide composition of sense and antisense strands. This property generates two very simple parameters - [A]/[T] and [G]/[C] of the sense strand - which could be used for discrimination of open reading frames as coding sequences with very high, statistically described level of significance. The paper contains a description of the method of ellipse of concentration in the two parameter space, which can close coding sequences inside, leaving a big fraction of noncoding sequences outside the ellipse.