Comparative Immunology of Selected Wild Types,Varieties and Mutants of Chlamydomonas*

SYNOPSIS. Rabbit antisera to strains of different mating types of Chlamydomonas moewusii and to one strain of C. eugametos were tested against strains of C. reinhardti, C. eugametos, and C. moewussi, and against strains of 2 varieties and 6 mutant types of C. moewusii. Technics of double diffusion, absorption, and immunoelectrophoresis revealed marked serological differences between the sexually incompatible, distinct genetic species C. moewusii and C. reinhardti. Less distinct serological differences were resolved between C. moewusii and the so-called “species”C. eugametos, which is sexually compatible with the former, thus reconfirming the conspecificity between the 2 strains as suggested by Gowans. Marked serological differences were noted between C. moewusii and 2 of its varieties (C. moewusii var. tenuichloris and C. moewusii var. rotunda) which constitute 2 additional genetic species because of sexual incompatibility between themselves and with C. moewusii. Wild types and certain mutants of C. moewusii were compared serologically and could be distinguished on this basis. Strains of different mating types as well as certain mutant strains (e.g., paralyzed flagella, flagella-less, twins and monsters) could be differentiated serologically altho differences were often very subtle. Some antigens were common to organisms tested.