Fig. 2. Mouse and chick hindbrain cells mix freely in short term aggregation cultures. (A,B) Confocal photomicrographs of aggregates consisting of E9.5 mouse cells from even- and odd-numbered rhombomeres (r) (even, red; odd, green) and (D,E) from E9.5 mouse and HH stage14 chick cells from the same rhombomere (mouse, red; chick, green). The bar chart in C shows a mean number of mixed and segregated aggregates. The relative proportion of each of these categories is expressed as percentage of the total number examined. Note that even-odd pairs of rhombomeres segregate from each other (r2/3, 68%; r4/5,71%), whereas cells from even pairs of rhombomeres mix freely (78%). In the bar chart in F, cells from the same rhombomere (r5; r6) in chick and mouse mix freely (81%; 83%). m/m, aggregates between mouse rhombomeres; m/c, aggregates between mouse and chick rhombomeres.