JORDAN R. BROCKway to see these results at the genetic
level and the genomic level,” he says.
The results line up nicely with the
known history of rice agriculture, he
adds, but the study couldn’t confirm
that the genes found to have been under
selective pressure really do control the
rice-like phenotype in barnyard grass.
His group is now working on follow-up
experiments to more conclusively deter-
mine the relationship between the mim-
ics’ genes and phenotypes.
Olsen also studies a variety of rice
known as weedy rice, an offshoot of
domesticated rice that’s re-adopted
some characteristics of wild plants that
farmers find undesirable. Like other
weeds, he explains, weedy rice plants
are “aggressive competitors in crop
fields. But at the same time, they aren’t
actually wild species; they’re really spe-
cifically adapted to these agricultural
environments that we’ve created.” Such
a system, he explains, can lend insightinto whether the genes that control cer-
tain traits differ between truly wild rice
and domesticated rice with a rebellious
streak. “It’s just such a fascinating phe-
nomenon, this evolution of... these
weedy species that are exploiting crop
environments,” he says.
As Olsen takes a closer look at barn-
yard grass genetics, Fan is planning to
apply the approach from their recent
study to other species. His mind still
on Vavilov, Fan wants to use genomic
sequencing on rye and oat to see
whether their phylogenies show evi-
dence that they were selected based on
mimicry of wheat.
Indeed, the barnyard grass study
“adds an impetus to going after and
looking at some of these other cases
that had been well documented pheno-
typically, but not at the genomic level,”
says Elizabeth Kellogg, a plant geneticist
at the Donald Danforth Plant Science
Center in St. Louis who collaborates
with Olsen but was not involved in the
new work. “That is, we don’t know what
specific genes were selected, and I think
there [are] clearly now opportunities to
go after those specific genes.”
—Shawna WilliamsNOTEBOOKBLENDING IN: A variety of barnyard grass takes
on a rice-like appearance early in its lifecycle
(right), growing upright instead of staying low to
the ground like its close relatives (left).Did you know that
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