Rachel Moran
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rachelmoran.bsky.social
Rachel Moran
@rachelmoran.bsky.social
1.6K followers 1.4K following 28 posts
Assistant Professor in Ecology & Evolution at UChicago. Evolutionary genomics and behavior in fishes. (she/her)
https://rachelmoranlab.com
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rachelmoran.bsky.social
Work from @brynnjohnson13.bsky.social's thesis investigates why neighboring hybrid zones between orangethroat and orangebelly darters followed different trajectories: long-term coexistence vs. collapse. Warming amplifies competitive asymmetry, influencing whether hybrid zones persist or collapse.
Male Etheostoma pulchellum (small fish with red and blue stripes on it's body and red and blue fins) Male Etheostoma radiosum spp. (small fish with red and blue fins and brown body)
October 24, 2025 at 6:33 PM
rachelmoran.bsky.social
New sex determining regions can trap or release nuclear-encoded mitochondrial genes, creating pulses of hybrid breakdown and leaving genomic scars.
Broadly, this raises the possibility that speciation may follow predictable patterns shaped by inheritance asymmetries and genomic conflict.
Schematic chromosomes illustrate two genomic contexts for nuclear-encoded mitochondrial (N-mt) genes (orange). (A) N-mt genes within autosomal or pseudo-autosomal regions recombine freely and can track mitochondrial evolution, minimizing mitonuclear conflict. (B) Local capture of N-mt genes in a non- recombining sex-linked stratum (purple) constrains compensatory evolution, intensifying mitonuclear conflict (lightning bolts) and often generating heterogametic-biased hybrid breakdown. Conceptual timeline showing how cycles of sex-chromosome turnover modulate the intensity of mitonuclear conflict through time. Conflict is low under the ancestral sex-determining region (SDR). When a turnover event establishes a new SDR that captures an N-mt locus, conflict is amplified (upslope) as compensatory evolution is constrained in the non-recombining stratum. A subsequent turnover that frees that locus from the SDR relieves conflict (downslope). If a later turnover again captures a different N-mt locus, conflict rises anew. These repeated amplification-then-relief cycles predict pulses of hybrid incompatibility and leave alternating genomic “scars” of reduced introgression at formerly sex-linked regions.
October 10, 2025 at 3:54 PM
rachelmoran.bsky.social
First pop gen paper from our lab! We find repeated evolutionary turn over of sex chromosomes in darters contributes to reproductive isolation. Turnover may be an escape hatch to resolve mitonuclear conflict & neo sex chromosomes evolved via a rare recessive mutation. www.biorxiv.org/content/10.1...
Top left: Results of genome-wide association study (GWAS) for sex in E. caeruleum, E. radiosum, and E. spectabile showing sex chromosome turnover has occurred repeatedly. Top right: Phylogeny showing sex chromosome turnover in darters and non-darter percids. Chromosome 9 is the putative ancestral sex chromosome, shared by Perca flavescens and multiple members of the orangethroat darter complex (e.g., E. spectabile, E. pulchellum). Bottom: Schematic depicting repeated turnover of sex chromosomes as a mechanism to resolve mitonuclear conflict and promote speciation.
September 4, 2025 at 5:32 PM
rachelmoran.bsky.social
Our lab is moving! I’m thrilled to be joining the Department of Ecology & Evolution at the University of Chicago this fall. I’ll be recruiting PhD students so please spread the word and reach out if interested!
University of Chicago campus University of Chicago campus
June 2, 2025 at 9:30 PM
rachelmoran.bsky.social
My lab made Pokémon cards featuring Texas fishes for our Darwin Day exhibit
Pokémon style cards featuring fishes found in Texas, including orangethroat darters, Guadalupe bass, longear sunfish, alligator gar, and channel catfish
February 10, 2025 at 4:38 PM
rachelmoran.bsky.social
Very grateful that our lab will be funded by an
NIH #R35 #MIRA for the next five years! We will leverage repeated evolutionary gain of paternal care in darters to study the genetic and neural basis of this complex social behavior.
July 10, 2024 at 2:37 PM
rachelmoran.bsky.social
New cavefish work led by Evan Lloyd (Keene lab) and Fanning Xia (Rohner lab)! We show an apparent lack of aging in cavefish despite insomnia, diabetes, and obesity traits. Our findings suggest cavefish have evolved genetic resilience to compensate for loss of sleep, elevated DNA damage, & diabetes.
Transcriptional response to aging is diminished in cavefish across tissues
April 24, 2024 at 5:10 PM
rachelmoran.bsky.social
My PhD student ⁦‪@taylorblack.bsky.social‬⁩ made a coloring book of endemic Texas fishes with Texas Parks & Wildlife!

www.facebook.com/share/p/oWnA...
March 15, 2024 at 6:14 PM
rachelmoran.bsky.social
We had a blast talking about fish diversity and evolution at our EEB #DarwinDay event!
March 2, 2024 at 3:34 AM
rachelmoran.bsky.social
One of my grad students gave me this darter shirt!
December 17, 2023 at 2:06 PM
rachelmoran.bsky.social
Celebrating a successful semester with the lab 🎉
December 17, 2023 at 2:06 PM
rachelmoran.bsky.social
Kiedon and Taylor breaking in our new cryostat! 🐟🧠🧪
Two researchers at a cryostat machine.
September 26, 2023 at 9:32 PM