Figure 1.—

Expected meiotic segregation pattern of chromosomes of a triploid. In this figure, we show the meiotic segregation of two homologs in blue and in red. The three copies of each homolog are shown as lines with long dashes, short dashes, or an uninterrupted straight line. Following the second meiotic division, one would expect to get two disomic spores and two monosomic spores for each chromosome. In this depiction, the sister spores “a” and “b” are disomic for the red homolog and monosomic for the blue homolog, whereas the sister spores “c” and “d” have the reciprocal pattern. With equal frequency, one would observe a pair of doubly disomic sister spores and a pair of spores that are monosomic for both chromosomes. In this figure, we have not shown recombination between the homologs, although such exchanges occur in most tetrads.