Honors thesis leads Pia Schwarz to publish first first-author paper

The Oxford Academic journal, Evolution, has published work by our undergraduate graduate, Pia Schwarz. The project started as her UB Honors thesis. Now, Schwarz is first-author of the article, 'Mosaic tri-lineage secondary contact shapes diverse genomic outcomes in darters'. As a student-athlete in our undergraduate program, Schwarz worked with Trevor Krabbenhoft, studying evolutionary genomics, speciation, and hybridization in North American stream fish. Currently, Schwarz is enrolled in the PhD Program at Yale.

Journal Article

Mosaic tri-lineage secondary contact shapes diverse genomic outcomes in darters 

Pia F Schwarz, Trevor J Krabbenhoft, Thomas J Near, Daniel J MacGuigan

Abstract: Speciation does not always lead to complete reproductive isolation, which can result in hybrid zones with gene flow. In freshwater fishes, secondary contact and hybridization can arise when river courses shift. Shifting river courses can create physical and ecological dispersal barriers, producing fragmented species distributions within the same stream system. Here we investigate a secondary contact zone in western New York (USA) between the Tessellated Darter (Etheostoma olmstedi) and the Johnny Darter (Etheostoma nigrum), integrating double digest restriction site associated DNA sequencing (ddRADseq), low-coverage whole genome sequencing (lcWGS), and mtDNA datasets. Our analyses reveal a complex tri-lineage hybrid zone of E. olmstedi and two divergent E. nigrumlineages. lcWGS and ddRADseq approaches yield similar overall results for population genetic structure; however, the two approaches differ in estimates of the magnitude of population differentiation. Several sites with ongoing admixture are proximate to stream confluences and form a temporally stable mosaic of hybridization across the contact zone. We observe active and apparently stable states of hybridization, supporting the hypothesis that niche partitioning by stream size maintains species identity. The species and populations in the contact zone maintain high levels of genome-wide differentiation across streams. Our study provides insight into the dynamic process of secondary contact and highlights the array of possible genomic outcomes of hybridization.

—Oxford Academic Journal, Evolution, International Journal of Organic Evolution

Undergraduate Graduate

Pia Schwarz

Pia Schwarz.

Pia Schwarz

"One of the biggest impacts in setting me up for a research career was my honors research project which I completed in lab of Dr. Trevor Krabbenhoft. Being accepted into the Biological Sciences Honors program opened a new door to explore my research interests in speciation and to complete a research project during my senior year. Both the technical and soft skills that I acquired while completing my project prepared me for developing my own projects in my PhD."

—Pia Schwarz
Recipient SUNY Chancellor's Awards for Student Excellence 2022
Graduated 2022
PhD student at Yale University

What was your career goal when you graduated, and where are you up to on that journey?

When I graduated, my career goal was to become a researcher and potentially a professor down the road. I was aiming to develop professionally in my research field as a population geneticist and computational biologist. I am currently pursuing a PhD in Ecology and Evolutionary Biology at Yale University. In my PhD, I study the role of plant immunity in speciation using a combination of quantitative genetics approaches and computational genomics tools. I have been presenting my research at Evolution and Speciation conferences to share my ongoing research and to build a professional network.

What are you currently working on professionally?

In my PhD I study the mechanisms that underlie the formation and maintenance of species boundaries in wildflowers of the genus Mimulus. Specifically, I am working on a set of projects to uncover the role of plant immunity in the evolution of intrinsic postzygotic reproductive barriers between species. My research focusses on a genetic incompatibility in hybrids called hybrid necrosis, which is associated with phenotypes such as leaf yellowing, wilting, cell death and dwarfism. I am currently mapping the genetic basis of hybrid necrosis and dwarfism in Mimulus hybrids between two species to understand the role of immune genes in the hybrid necrosis incompatibility. Plant immune genes are one of the most rapidly evolving gene families in nature in response to an arms race relationship between pathogens and the host immune system. Since this process leads to high and rapid genetic diversification, I am exploring the landscape of immune genetic diversity, in a class of plant disease resistance genes called NLRs across many species in a Mimulus species complex. My goal is to understand how natural variation shapes the evolutionary landscape of immune system incompatibilities.


How has the Department of Biological Sciences helped you prepare for your goal?

One of the biggest impacts in setting me up for a research career was my honors research project which I completed in lab of Dr. Trevor Krabbenhoft. Being accepted into the Biological Sciences Honors program opened a new door to explore my research interests in speciation and to complete a research project during my senior year. Both the technical and soft skills that I acquired while completing my project prepared me for developing my own projects in my PhD.

What faculty member or class brings back the best memories?

One of my favorite memories is TA’ing BIO 200 with Dr. Poulin! I loved my TA cohort community, and grading the lab final exams all together in one room right before Christmas was a lot fun!

What is your advice to the current/future BIO students?

My advice is to seek out undergraduate research opportunities and use research projects as a way to explore areas of Biology and research that excite you. This process takes time, and it can involve rounds of trial and error, and many twists and turns until you find your “niche” in Biology. Persevere and follow your passions!

Pia Schwarz, UB Student Athlete

Photo courtesy of UB Bulls.

Pia Schwartz, Photo courtesy of UB Bulls.

Throughout her work in our program, Schwarz was a student-athlete on the UB Women’s Tennis team, and competed for UB at the Mid-American Conference and Northeast Regional Championships, where she was named to All-Conference and All-MAC Tournament Teams and won numerous awards. 

Awards and distinctions

  • BS in Biological Sciences, Summa cum laude, Highest Honors in Biological Sciences 2022
  • State University of New York (SUNY) Chancellor’s Award for Student Excellence 2022
  • Mid-American Conference Medal of Excellence 2022
  • Mid-American Conference Presidential Award 2022
  • Mid-American Conference Distinguished Scholar Athlete 2021 
  • Mid-American Conference Academic All-MAC Team 2021/2022
  •  Intercollegiate Tennis Association All-Academic Scholar Athlete 2021/2022
  • Mid-American Conference Academic Honor Roll 2021/2022
  • University at Buffalo Experiential Learning Network Conference travel fund 2022
  • All-MAC 1st Team Women’s Tennis 2021
  • All-MAC 2nd Team Women’s Tennis 2022
  • MAC Women’s Tennis player of the week 03/11/2022
  • Buffalo Renaissance Foundation UB Athletics Scholarship 2022


Research Presentations

  • Poster Presentation, Open Symposium, ESEB 2022, Prague (CZE), August 2022 “Genome Resequencing Reveals Hybrid Zone Dynamics of Secondary Contact in Darters (Teleostei:Percidei)” Pia Franziska Schwarz, Dan MacGuigan, Trevor J. Krabbenhoft.
  • Conference Talk, Hybridization Symposium, Evolution 2022, Cleveland, OH, June 2022 “Genome Resequencing Reveals Hybrid Zone Dynamics of Secondary Contact in Darters (Teleostei:Percidei)” Pia Franziska Schwarz, Dan MacGuigan, Trevor J. Krabbenhoft.
  • Platform presentation, Biological Sciences Honors Symposium, University at Buffalo, The State University of New York, Buffalo, NY, May 2022.“Beyond Research”, awarded with Highest Honors in Biological Sciences.
  • Poster Presentation, Biological Sciences Honors Symposium, University at Buffalo, The State University of New York, Buffalo, NY, May 2022 “Genome Resequencing Reveals Hybrid Zone Dynamics of Secondary Contact in Darters (Teleostei:Percidei)” Pia Franziska Schwarz, Dan MacGuigan, Trevor J. Krabbenhoft.
  •  Poster Presentation, Celebration of Student Excellence, University at Buffalo, The State University of New York, Buffalo, NY, April 2022
    “Genome Resequencing Reveals Hybrid Zone Dynamics of Secondary Contact in Darters (Teleostei:Percidei)” Pia Franziska Schwarz, Dan MacGuigan, Trevor J. Krabbenhoft.