Fig. 4.

Segregation patterns of two different microbial species are qualitatively similar but different in detail. (A and B) Both bacteria (E. coli) and yeast (S. cerevisiae) colonies exhibit spatial gene segregation when they grow colonies on agar plates. However, the number of (surviving) sectors is much larger in yeast colonies. For the linear inoculations (C and D), the Petri dish was gently touched with a sterile razor blade that was previously wetted by a liquid culture of a binary mixture of mutants. (E and G) Continuous patches of boundary regions and homeland (bounded by dashed line) at a magnification of ×51 for E. coli (E) and yeast (G). (F and H) Images at single-cell resolution (×100). (F) Tip of a sector dies out (E. coli). (H) Section boundary at the frontier (yeast).