MANHATTAN, KAN. -- A Kansas State University researcher's plant genetic work is rooted in the sunflower state.
Mark Ungerer, associate professor of biology, has two major research projects that involve evolutionary change in sunflowers, the state flower of Kansas.
"What we do in the lab is referred to as ecological or evolutionary genetics," Ungerer said. "We study naturally occurring species and try to understand the genetic basis or genetic underpinnings of natural variation."
There are more than 50 species of sunflowers. Some are annual plants -- meaning they germinate, flower and die in one year -- and some are perennial plants that grow and bloom every year and live longer.
Ungerer's first project focuses on five species of annual sunflowers: two parent species and three hybrid derivative species. All three hybrid species arose from ancient hybridization events between the same two parents -- an unusual way for new species to develop, Ungerer said.
"What also makes the system unique is that the hybrid species are recently derived in the last half a million years," Ungerer said. "It seems like a long time, but that is actually pretty recent in evolutionary terms."
But there is another interesting aspect of the three hybrid species: While they have the same number of chromosomes as the two parent species, the hybrid species' genomes are 50 to 75 percent larger in terms of the amount of DNA.
Ungerer's research team made an important discovery that explains this DNA difference. The researchers studied long terminal repeat, or LTR, retrotransposons, which are mobile genetic elements that can copy themselves and insert the copies into various chromosome locations. Ungerer's team discovered that the hybrid species and the parent species were different because of massive proliferation events, or rapid reproduction, of the LTR retrotransposons. Not only that, these transposable elements are still active
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Kansas State University