An example of merging mixture components. The Sca-1 expression data for the unsorted population of EML cells at 264 h is shown in the histogram. At each step of the merging algorithm, the fitted profile is shown as a thick grey curve, and the individual components in think black curves. (a) Initial profile computed by Greedy EM with g = 5, Entropy = 2351. (b) Merged profile with g = 4, Entropy = 573. Combining a group of components in the left significantly reduces entropy. (c) Merged profile with g = 3, Entropy = 297. (d) The final merged profile with g = 2 components and Entropy = 48.