[A system for analysis of yeast mutants deficient in the genetic recombination process].

A system of molecular-genetic methods intended for analysis of yeast Rec-mutants was developed. A number of plasmids containing noncomplementing mutations in the ADE2 gene and different selective markers were constructed. The system was based upon the phenomenon of interplasmid intragenic recombination during transformation and mitotic division. Transformation of yeast cells with the plasmid containing two long right repeats allowed to estimate the efficiency of intraplasmid crossing-over. The system also allows to study plasmid-chromosomal interaction. To check up the system proposed, a well known rad50 and rad52 mutants were used. The rad52-1 mutation was found sharply decreased the levels both intra- and interplasmid recombination events. On the other hand, rad50-1 mutation has not influences or stimulates the processes. Thus, the system proposed efficiently distinguishes the mutants deficient in different stages of recombinational process.