The estimation of conversion parameters and the control of conversion in Ascobolus immersus

Summary Pasadena strains of Ascobolus immersus were used to study the controls of gene conversion. Formulae were derived for estimating conversion parameters according to different hybrid DNA models of recombination. Genetic factors influencing conversion were determined by using genetically different isolates and using alleles before and after they had undergone conversion. Conversion properties at particular sites were greatly affected by genetic factors very near to those sites: the nature of the mutations and factors elsewhere in the genome were much less important. These genetic factors and temperature both affected the frequency of hybrid DNA formation at particular sites, the efficiency of mispair correction and the relative frequencies of correction to wild-type or mutant. The effects of temperature on conversion parameters were usually complex.