Kansas State Flower Receives Scientific Attention:
K-STATE BIOLOGY PROFESSOR RECEIVES GRANT FROM THE NATIONAL SCIENCE
FOUNDATION TO STUDY EVOLUTION OF STATE FLOWER
|
Source: Mark Ungerer,
785-532-5845,
mcungere@k-state.edu
News release prepared by:
Stephanie Jacques,
785-532-6615,
sjacques@k-state.edu |
MANHATTAN -- Anyone who has seen Kansas prairies in late summer to early
fall can attest to the abundance of sunflowers decorating fields and
lining roadways, giving Kansas the well deserved nickname, the
Sunflower State.
Despite its beauty, the sunflower is more than just a pretty flower. To
scientists, such as Mark Ungerer, assistant professor in the Division
of Biology at Kansas State University, it is a prime example of the
unique adaptability of plants.
In March, the National Science Foundation awarded Ungerer a $610,000
grant to continue his research on the genomic evolution of three
species of hybrid sunflowers: anomalous sunflower, Desert sunflower and
Pecos sunflower. The independent origins of these three hybrid species,
from the same two parents, the common sunflower and Plains sunflower,
raised some intriguing questions for Ungerer that inspired his grant
proposal.
As Ungerer reviewed the genetic data from all five species of sunflowers
he noticed something weird. The two parental species and the three
hybrid species all have 34 chromosomes, but the genomes, the entire
hereditary information encoded in DNA, of the hybrid species is far
larger.
"What is strange is that the hybrid species have about 50-75 percent
more DNA than the parental species and that doesn't make sense, given
what we know about their origins. If they all have the same number of
chromosomes how could they possibly have more DNA? Where did it come
from?" Ungerer asked.
Given that all three hybrid species grow in extreme environments,
Ungerer hypothesizes that environmental stress may have caused the
activation of a typically inactive class of transposable elements of
DNA, called long terminal repeat retrotransposons.
"These elements are DNA sequences related to infectious retroviruses and
are capable of multiplying and inserting copies of themselves into new
positions in their host genome. Because of their replicative abilities,
long terminal repeat retrotransposons, when activated, can result in
massive genomic expansion and restructuring," Ungerer said.
"We are trying to understand the circumstances that caused
retrotransposons to become active and proliferate in these sunflowers
and the evolutionary and ecological consequences of these proliferation
events," Ungerer said. He also noted that retrotransposons are not just
found in sunflowers but in virtually all plants and animals, even
humans. In his grant proposal , Ungerer said knowledge of the causes
and consequences of this activation could deeply impact our
understanding of the role of these genetic elements in organism
evolution.
During the course of his three year study, Ungerer will be testing his
theory using the controlled greenhouse environments available at
K-State to mimic possible environmental stresses on early generation
hybrids from the two parental species. Ungerer also will be collecting
samples from wild sunflowers in hybrid zones throughout Kansas,
Nebraska, Colorado, Utah, Arizona and New Mexico.
Ungerer received his Ph.D. in 2000 from Indiana University in ecology
and evolutionary biology. He joined K-State in November 2003. |
