MAL SEQUENCE ON CHROMOSOME-IV OF SHOCHU Y EAST

In the yeast Saccharomyces cerevisiae, five unlinked MAL (maltose ferm entation gene) loci, MAL1, MAL2, MAL3, MAL4, and MAL6 have been identi fied. We surveyed the chromosomal location of the MAL homologous seque nce for some industrial yeasts, and found that shochu yeasts, sake yea sts and wine yeasts isolated in Japan have a MAL homologous sequence o n their chromosome IV, identified by hybridization analysis with a TRP 1 gene probe. By pulse field gel electrophoresis (PFG)-Southern hybrid ization analysis of segregants isolated from a hybrid between a haploi d spore from shochu yeast SH-4 and a mal- laboratory strain, this homo logous sequence originating in SH-4 could express maltose fermentabili ty. Therefore, we named this sequence MAL7. These MAL+ segregants indu ced maltase activity more slowly than the MAL6 segregants did. We clon ed this sequence of shochu yeast SH-4 by polymerase chain reaction and found it had high homology to MAL6.