Foster notes. The benefits of large slug
STUDying SoCiaL evoLUTion in miCRoCoSm
size, however, show that sometimes the
ecological benefits of cooperation with
What are the causes, mechanisms, and effects of social
genetic strangers can override the costs.
evolution? Rice evolutionary biologists David Queller and
“Both relatedness and ecological benefits
Joan Strassmann believe that the single-celled social
are also important in social insects and verte-
brates,” says Foster, “which suggests that there
amoeba Dictyostelium discoideum might provide some of
are general rules of social evolution.” the answers. To find out, they are teaming with geneti-
Future studies of slime mold are likely not
cists and developmental biologists from Baylor College
only to provide new insights into sociality, evolu-
of Medicine on a five-year project funded by a new
tion, development, and molecular biology but to fos-
ter a new interdisciplinary synergy between these
National Science Foundation program dedicated to
fields. “The real advances in understanding,” Strass- taking on grand challenges in biological research.
mann says, “will come from interdisciplinary work us-
ing evolutionary theory and social theory in a molecu-
The project brings togeth- amoebae work collectively
lar framework.”
er experts in genomics and to form colonies. Though the
“Sociobiology has largely been practiced in the ab-
social evolution to provide the cells in these colonies coop-
most thorough understand- erate, prior studies by Queller
ing yet of the genetic basis and Strassmann have shown
and evolutionary history of how groups of amoebae that
complex social behavior. It is contain dissimilar genes com-
one of just six inaugural proj- pete within the colony to gain
ects unveiled in the launch of a reproductive advantage.
the NSF’s Frontiers in Integrat- “The genetic tools and
ed Biological Research pro- simplicity of sociality in so-
gram. Approximately half of cial amoebae make it easier to
the $5-million award will go study the processes of coop-
to each institution. Baylor co- eration and conflict that also
principal investigators include operate in other organisms,”
Adam Kuspa, professor of de- says Strassmann.
velopmental biology; Gad The social evolution proj-
Shaulsky, assistant profes- ect has four goals. First, it will
sor of molecular and human uncover the genes and molec-
genetics; and Chad Shaw, in- ular pathways underlying so-
structor of molecular and hu- ciality. Second, it will probe
man genetics. the evolutionary history of
“Some of the most sig- these genes. For example, the
nificant transitions in evo- research will test whether so-
lution—the emergence of cial forces create significant
chromosomes, cells, eukary- evolutionary pressures, and
otes, and multicellular organ- it will demonstrate the social
isms—occurred when former- function of ancestral genes by
Professors of ecology and evolutionary biology
ly separate entities overcame recreating them and testing
David Queller and Joan Strassmann
conflicts and merged into a them in vivo. Third, the proj-
greater whole,” says Quel- ect will generate experimen-
ler, principal investigator on tal evidence for how opportu-
sence of knowledge of the underlying genes,” adds
the project. “So it’s clear that nistic, nonaltruistic behavior
Queller. That’s about to change. He and Strassmann
understanding social evolu- is controlled—a process that
have received funding from the National Science
tion is central to understand- was essential in the major
Foundation that will allow them to team with Bay-
ing the very structure of life, evolutionary transitions noted
lor researchers and, together, hunt down the spe-
yet very little has been done above. Finally, the knowledge
cific genes underlying slime mold strains’ coop-
to apply the modern tools of gained in the lab will be used
erative and cheating behaviors—with an eye
genetics and genomics to the to understand how social evo-
toward learning, among other things, how evo-
study of social evolution.” lution works in the wild.
lution limits the proliferation of cheating
Dictyostelium discoide-
genes.
um is a favorite model system —Jade Boyd
among developmental and
cell biologists for studying so-
cial evolution because social
Winter ’04 35
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