QUANTITATIVE ANALYSIS OF THE PROPORTIONS OF THE DICTYOSTELIUM DISCOIDEUM ASEXUAL FRUITING BODY

Publisher Summary This chapter discusses the quantitative analysis of the proportions of the Dictyostelium discoideum asexual fruiting body. The asexual fruiting body of Dictyostelium discoideum represents one of the simplest multicellular organisms. It is comprised of three cell types, spores, stalk cells, and basal disc cells, which form a linear array. As few as 10 cells and as many as 105 cells make up the fruiting body that looks roughly the same over this huge size range. The chapter also discusses the relationship between spores, stalk, and basal disc cells. Spore numbers are linearly related to total cell numbers in fruiting bodies of different sizes in strain X22, whereas both stalk cell numbers and basal disc cell numbers are exponentially related to total cell numbers. This means that proportions of the different cell types are not size invariant. For example, strain X22 fruited in the light instead of the dark has a greater percentage of both stalk and basal disc cells, but the equation relating these two cells types is unaltered. Strain X22 is a haploid segregant of the diploid DP4. There is a difference in the proportioning of strains M28 and NP14 that is statistically significant. The proportioning in strain X22 is statistically indistinguishable from strain M28. This shows that it will be possible to analyze proportioning mutants genetically.