Human genetic diseases: a cross-talk between man and yeast.

A sequence similarity search has been carried out against the complete Saccharomyces cerevisiae genome to identify the yeast homologues of human disease-associated genes. Using the BLAST algorithm (Basic Local Alignment Search Tool), it was found that 52 out of the 170 disease genes identified without reference to chromosomal map position and 22 of the 80 (27.5%) positionally cloned genes match yeast genes with a P-value of <e(-40). The percentage of the disease genes identified by positional cloning which bear homology to yeast is similar to that of a random collection of human cDNAs. The biochemical and physiological functions of the large majority of these human genes remain poorly understood and, even though a strict conservation of function cannot safely be assessed from structural homology analysis without the support of experimental and three-dimensional data, functional analogies can often be established between the human and yeast genes.