Research in Iowa State’s Department of Ecology, Evolution and Organismal Biology (EEOB) has been garnering a lot of attention — and support — from the National Science Foundation (NSF) this past year. In 2016, eight faculty received grants from the NSF to support their exciting research in evolutionary biology.
The funding, totaling more than $2.9 million, allows faculty to get down to the business of understanding how sex chromosomes evolve, how fig plants and fig wasps can diversify through pollination, how new mathematical models can better represent evolutionary patterns, and more.
“It speaks to the remarkable strength of our program,” said Jonathan Wendel, Distinguished Professor and Chair of the Department of EEOB.
Funding was awarded to seasoned researchers as well as newer faculty members who represent the future of Iowa State University.
"People in this department are asking very interesting questions from very different perspectives," said Nicole Valenzuela, associate professor of EEOB who received one of the grants. "The very high rate of funding that we’ve had is a testament to the degree of high regard that our peers have for the research that we do."
Below, meet a few of the faculty who have earned NSF grants for their exciting research.
Nicole Valenzuela: Evolution of Developmental Mechanisms
Nicole Valenzuela joined the Iowa State faculty in 2004. She has received several NSF grants over her career, the most recent to study dosage compensation, a method by which organisms make up for uneven numbers of copies of genes between sex chromosomes and other chromosomes. This study is part of her research to understand how sex chromosomes evolve and how different mechanisms of sex determination come about.
Valenzuela studies turtles, which have several different methods of sex determination. Some species of turtles have a temperature dependent mechanism to determine the sex of their offspring. Others inherit their sex through chromosomes — determined either by the father’s genes, called XY determination, or the mother’s, called ZW determination.
"I got interested from a conservation standpoint," Valenzuela said. "Why would a species have a mechanism that depends on the environmental temperature?"
She wanted to know how the mechanism worked and whether temperature dependence put turtles in more danger from environmental changes than turtles and other species with a chromosomal sex determination.
The variation of sex determination within turtles makes them an excellent species to study how sex chromosomes and dosage compensation change and evolve over time.
"We have a wonderful system to explore to look at whether you get dosage compensation every time there is evolution of sex chromosomes, if it’s the same for XY or ZW or if there’s a fundamental difference, if it is local (gene by gene) or global (along entire chromosomes) every time, and so on," she said.
Tracy Heath: Advancing Bayesian Phylogenetic Methods for Synthesizing Paleontological and Neontological Data
Tracy Heath joined the Iowa State faculty in 2015. She uses statistical methods to study patterns of biodiversity in and across species, and received two NSF grants in 2016.
Her first grant will allow her to continue her research in understanding relationships between species in the context of time. Currently models to analyze fossil data with molecular data do not adequately account for the structure of the fossil record or geographic patterns of species sampling. Heath aims to develop new diversification models to account for these processes and improve estimations in dating, showing the rate of diversification through time more accurately.
Heath’s second grant is shared with John Nason, professor of EEOB, for a joint project to study the coevolution of species. They will use the fig plant and the fig wasp as a model of a host and it’s “mutualist,” an organism that benefits from the host and gives a benefit to the host in return.
"We know so little about the fig, fig wasp system even though it’s one of the classic examples of mutualism," Heath said.
The fig genus (Ficus) has 850 different species, all of which require a wasp pollinator. Wasps lay eggs in fig seeds, where they remain until they mature. The daughters then carry pollen from where they were born to pollinate the next fig plant.
There is a close, almost one-to-one, pairing of specific wasp species and fig species. Heath and Nason intend to study the places where this pairing is less clear with host switching and hybridization in order to improve understanding of how the species evolve and diversify together.
Dean Adams: Extension of phylogenetic comparative methods for evaluating within-species, microevolutionary patterns in a macroevolutionary context
Dean Adams, professor of EEOB and statistics, joined the Iowa State faculty in 2001. He researches ways to merge mathematical models for handling multiple variables to evolutionary models.
Adams’ most recent grant is for research on incorporating multivariate traits across species. Current models to study across species only allow for looking at an average of a single trait. Adams wants to be able to study multivariate traits and include within-species variation across species.
"By being able to incorporate the within-species trends — not just the average specimen but the trend itself — we have the ability to ask how those trends evolve," Adams said. "So it’s not just, ‘how did body size evolve over time?’ but ‘how did the body size-temperature relationship change over time?’"
This will open the door for new questions of research about species that recognizes the rich patterning within species. Adams also works to get the tools he develops into the hands of biologists through education and outreach trainings around the world.
Other grants received by faculty in evolutionary biology include grants to Anne Bronikowski, professor of EEOB who joined the faculty in 2004, to study genetic and physiological indicators of population extinctions, Fredric Janzen, professor of EEOB who joined the faculty in 1994, to study epigenetic responses to environmental variation, Matthew Hufford, assistant professor of EEOB who joined the faculty in 2013, to study how corn adapts to different elevations and environments, and Jonathan Wendel, Distinguished Professor and Chair of EEOB, who joined the faculty in 1986, to study the genomic basis of cotton domestication and genome evolution in approximately 50 species of cotton.