Fig. 9. Some of the tetrad types predicted after sporulation of a diploid strain resulting from the cross AB x ab, where A and B are on different chromosomes. Note that parental ditypes and nonparental ditypes should occur with equal frequency. If at least one of A and B is sufficiently far from its centromere to behave as if unlinked to its centromere, then 4 different tetratypes can be generated, each with a frequency equal to that of the parental and nonparental ditypes. Two of the possible tetratypes are shown in the figure.