Ļć½¶Ö±²„biological sciences faculty member working to uncover evolutionary mysteries
Contact: Sarah Nicholas
STARKVILLE, Miss.āGroundbreaking research on the evolutionary history of the HeliconiusĀ butterfly is the topic of three current articles involving a Mississippi State biological sciences faculty member.
Associate Professor Brian Counterman is part of a research team whose new study is featured on the November cover of āScienceā shedding light on phylogenomicsāthe intersection of the fields of evolution and genomicsāand the ability of Heliconius to split into many species within a small window of time, a topic that has made the butterflies prime research subjects for evolutionary biologists for decades.Ā The article is available online at .
āFor the past 30 years, Ļć½¶Ö±²„researchers have made strides in developing Heliconius butterflies as a model organism for studying the origin of species and evolutionary novelties,ā Counterman said.
For the āScienceā study, researchers used a new low-cost sequencing strategy to assemble 20 whole Heliconius genomes to reconstruct a comprehensive picture of the Heliconius diversifying process with unprecedented detail.
Their results show the āevolutionary treeā of species relationships, assumed by scientists for decades, actually looks more like an āevolutionary bush.ā
āThe visual representation of evolutionary relationships popularized by Darwin have been imagined like a phylogenetic treeāeach species represents the tip of a tree branch and the branch represents the speciesā history,ā Counterman said.
āHowever, the āScienceā paper shows that species have many different histories present in their genomes marked by many branches leading to the same tips of the phylogenetic treeāa ābush-likeā pattern,ā he said.
Counterman and colleagues āfound a lot of genetic exchange after speciation, specifically in the genes that control color patterns of butterfly wings. Their wing color patterns are warning signals to potential predators that they are toxic.ā
āThis study supports a growing body of evidence from a variety of organisms that hybridization and the exchange of genetic material between species can be an important driver of adaptive change,ā Counterman said.
For āScience,ā Counterman collaborated with a team led by researchers at Harvard University, including Jim Mallet, a former faculty member in MSUās Department of Entomology, where Mallet began his work on the genetics of Heliconius in the 1980s. Ā
TheĀ āScienceāĀ family of journals is published by the American Association for the Advancement of Science, the worldās oldest and largest general science organization.
Counterman and his students also published their research on butterfly wing colors in a November issue of āCurrent Biology,ā a peer-reviewed journal publishing original research spanning all areas of biology.
For this article, online at ,ā Counterman worked with a team led by the Smithsonian Tropical Research Institute to explore the predictability of evolution. Their findings reveal evolution may not be as predictable as previously hoped.
Jennifer L. Fenner, a doctoral student from Millport, Alabama, in MSUās Department of Biological Sciences, co-authored with Counterman the āCurrent Biologyā article detailing the new, cutting edge CRISPR gene-editing technology used to delete genes that influence wing color patternsātheir findings demonstrate āthe unpredictable complexity of evolutionary change.ā
āWe were surprised to find the species with mimetic color patterns did not have similar mutant color patterns,ā Counterman said. āAlthough the genes did influence color pattern in both species, they changed the color in very different ways.ā
A third article in āProceedings of the National Academy of Sciencesā and online at is in collaboration with a team at Cornell University and the University of Puerto Rico. Counterman and Ļć½¶Ö±²„graduate student Caleb Benson of Petal sought to uncover the DNA differences responsible for the rapid evolution of Heliconius wing color patterns.
The team used a combination of approaches involving genome sequencing and CRISPR-based genome editing to discover which pieces of DNA could change gene expression and butterfly wing color.
āThese findings challenged our understanding of how genes are regulated during development and how novel patterns can evolve in natural populations,ā Counterman said.
āIdentifying how specific DNA differences can change how an organism develops and what it looks like as an adult has important implications for understanding how biodiversity is generated in nature,ā Counterman said.
āProceedings of the National Academy of Sciencesā is the official journal of the National Academy of Science for the U.S., considered to be one of the most highly cited and comprehensive scientific journals that spans all fields of science.
āPublishing in all three of these highly regarded journals is tantamount to high quality scientific contributions made by the researchers at MSU,ā Counterman said. āThese studies build on MSUās legacy of excellence of research in the areas of evolutionary and genomics.ā
An Ļć½¶Ö±²„faculty member since 2010, Counterman received his Ph.D. from Duke University and has been studying the evolution and genetics of butterflies for the past 15 years.
Part of MSUās College of Arts and Sciences, the Department of Biological Sciences is online at , and the Counterman Lab at .
Ļć½¶Ö±²„is Mississippiās leading university,Ā available online atĀ .