My Mizzou Story
Kate Hertweck
Are Some Plants Genetically Programmed to Be Rare? Graduate Student Kate Hertweck Researches the Possibility
Kate Hertweck, a third-year graduate student in biological sciences, has a theory that some rare plants might be rare because of something in their chromosomes. She's received two grants in the past two years that enable her to continue doing field work — the necessary building block of most research.
Her first grant came from the Botanical Society of America, and the Society of Systematic Biologists granted her most recent award; with that money Hertweck will delve further into the chromosomal evolution of plants.
Hertweck's field work has taken her to the Ozarks and Texas, and she will travel to Mexico in October. She will search for particular specimens in the genus Tradescantia: spiderworts and wandering jews. These plants are noteworthy with regard to their chromosomes — in nature they hybridize with apparently little effort, and some of them have extra sets of chromosomes that are quite large and easily visible under a microscope.
Chromosomal changes can dramatically affect the ability of plants to survive, reproduce, and adapt. Wandering jews exhibit mechanisms of chromosome evolution that occur often in animals like rodents but are presumably rare in plants. For example, Robertsonian fusion is a process by which two chromosomes are dissected and subsequently united. Most important genetic material from the two chromosomes is maintained, but unnecessary parts are removed and the organism ends up with one less chromosome. Processes like these can add to the diversity of a population, which provides more genetic material upon which selection can act and may ultimately lead to the evolution of new species.
In plants, chromosomal changes may correlate with habitat preference or other ecological characters. Hertweck is attempting to determine how chromosomal characters relate to plant rarity or invasiveness in spiderworts. Wandering jews are an interesting group because plants within the family exhibit a wide variety of characteristics, so she can make comparisons between them.
J. Chris Pires, her adviser, encourages his students to develop and explore methods for analyzing chromosomal changes and other evolutionary mechanisms through a variety of novel approaches. Although such changes have been explored in cultivated plants like corn, rice and cotton, little is known about chromosomal changes in wild populations. Hertweck's trip to Mexico will allow her to obtain unique plant material from interesting environments to explore chromosome evolution.
Unfortunately, field work doesn't always go as planned. Some of the rare Texas species she had been told about have disappeared as habitats were urbanized or farmed. Her work can shed light on how plant chromosomes contribute to diversity and the resulting implications for preservation. Hertweck's research apparently has import in the field of botany — her first grant was awarded on the basis of her hypothesis: she was a first-year graduate student and had no preliminary data at the time.
August 2007