TUDIES of inheritance in the green alga Chlamydomonas reinhardi were initiated S to provide material for analysis of heritable alterations affecting the chloroplast and other cytoplasmic bodies. In this paper methods are presented for genetical analysis of this organism and the patterns of inheritance of several factors which show 2:2 segregation are described. Data from tetrad analysis are used for the detection of linkage, and to compute the approximate distance of each factor from its

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... ere. One factor has been found to show only first-division segregation, making available in Chlamydomonas the equivalent of ordered tetrads. These results will be compared with the non-Mendelian inheritance of streptomycin resistance previously reported in this strain (SAGER 1954) , and problems in the detection of non-chromo-soma1 inheritance will be discussed.