In 1989, Loomis and Kuspa, then a postdoctoral fellow in Loomis' laboratory, initiated a critical portion of the effort when they began the arduous task of constructing a physical map of the genes located on the six chromosomes of Dictyostelium.
The scientists mapped the location of several hundred genes on those chromosomes based on landmarks that had been discovered over the years, then created a set of 5,000 large DNA clones, each about 200,000 nucleotide bases long, that proved useful for other researchers in assembling the genetic sequences of Dictyostelium's genome. Another UCSD biologist involved in the genome effort, Christophe Anjard, an assistant project scientist in Loomis' laboratory, analyzed families of Dictyostelium genes and uncovered relationships with these genes in both animals and plants.
Dictyostelium is used as a model organism for studying cell polarity, how cells move and the differentiation of tissues. It also exhibits many of the properties of white blood cells.
Three years ago, another team of UCSD biologists discovered that two genes that are used by Dictyostelium to guide the organism to food sources are also used to guide human white blood cells to the sites of infections and play a role in the spread of cancer. (see: http://ucsdnews.ucsd.edu/newsrel/science/mcchemo.htm )
Dictyostelium usually exists as a single cell organism that inhabits forest soil, consuming bacteria and yeast. When starved, however, the single cells come together, differentiate into tissues and become a true multicellular organism with a fruiting body composed of a stalk with spores poised on top. This increases its utility in a variety of studies.
"An organism's relationship to humans depends on how related the proteins are that are found in the two cell types," says Kuspa. "You can make direct analogies, or you could learn general principles about how cel
Source:University of California - San Diego