Biology Department photograph montage

Karen Crow

Professor karencrow
Associate Professor
University of California, Santa Cruz
At SFSU Since: 
Hensill 214
Office Hours: 
Tues 3-5 pm
Office Phone: 
(415) 405-2760
Evolution and ecology of fishes, Ichthyology, Molecular evolution of duplicate genes, Evolutionary Developmental Biology (Evo-Devo)

 Research Interests:

In my research I use molecular approaches to understand the evolutionary forces that generate biological diversity, novelty, and reproductive isolation in fishes. 

My recent work has focused on a family of genes that specify body plan features-the Hox genes. Specifically, I have focused on the molecular evolution of HoxA11 and HoxA13 in ray-finned fishes, Hox cluster duplication in teleosts, and the putative relationship between genome duplication and the evolution of complexity and diversity in vertebrates. Based on this work, I  hypothesized that genome duplication may be an important factor in reduced probability of extinction. Other projects include investigating the role of Hox genes in the evolution and development of novel morphological domains such as  claspers in cartilaginous fishes, distally elongated fields in batoid fins, brood pouch in male pipefish (and relatives), paddlefish barbels, and distal elements in the gut of zebrafish and gobies. Additional projects in the lab are centered on aspects of reproductive strategies including the evolution of female Bateman gradients in surfperches (Embiotocidae), multiple embryos per egg capsule in skates of the genus Raja, and the evolution of plasticity in sex allocation in the simultaneous hermaphroditic gobies of the genus Lythrypnus.

In previous work, I have investigated questions varying in scale from paternity to genomics in ray-finned fishes, including genetic differentiation of sub-populations for conservation designation, and estimating phylogenetic relationships.  I have looked at conflict between hybridization and the maintenance of species boundaries, genomic conflicts associated with mechanisms of speciation, and alternative life history strategies including parental care, variation in courtship rituals, sexual selection, and sex allocation in hermaphrodites to evaluate how these strategies may contribute to species diversity.

While my research spans a range of topics, the underlying theme is to understand the evolutionary processes that contribute to the evolution of novelty and diversity.


Mandy HansenKaren D. Crow, and Katharyn Boyer. 2020. Invasive mangroves produce unsuitable habitat for endemic goby and burrowing shrimp pairs in Kāneʻohe Bay, Oahu, Hawai‘i. Sciencias Marinas. submitted

Karen D. Crow, Ara Sadakian, Noelle Kassly2020. The role of the 5’ HoxA genes in the development of the hindgut, vent, and a novel sphincter in a derived teleost (bluebanded goby, Lythrypnus dalli). Journal of Experimental Zoology, Part B. In press.

Michael Izumiyama, Satoshi Awata, Karen D. Crow. 2020. Evaluating the reproductive strategy and correlation between mating success and reproductive success of Ditrema temminckii: Is the number of fathers a good approximation for the number of mates? Copeia. In press. 

Michael Izumiyama, Michael Westphal, Karen D. Crow. 2020. In the surf zone: Reproductive strategy of the calico surfperch (Amphistichus koelzi)in a comparative context. Journal of Fish Biology 202096939– 949

John D. Swenson, Jeff Klomp, Robert A. Fisher, Karen D. Crow. 2018. How the Devil Ray Got Its Horns: The Evolution and Development of Cephalic Lobes in Myliobatid Stingrays (Batoidea: Myliobatidae). Frontiers in Ecology and Evolution.

Kayla Hall, Peter Hundt, John Swenson, Adam Summers, Karen D. Crow. 2018. Evolution of radial distribution in pectoral appendages of pelagic rays (Myliobatidae)-a derived group of batoids that evolved cephalic lobes in association with a shift from undulatory to oscillatory swimming. Journal of Morphology. doi: 10.1002/jmor.20837

Shannon Barry, Karen D. Crow. 2017. The role of HoxA11 and HoxA13 in the evolution of novel fin morphologies in a representative batoid (Leucoraja erinacea). EvoDevo: 8, 24.

Owens, MT, Seidel, SB, Wong, M, Bejines, TE, Lietz, S, Perez, JR, Sit, S, Subedar, ZS, Acker, GN, Akana, SF, Balukjian, B, Benton, HP, Blair, JR, Boaz, SM, Boyer, KE, Bram, JB, Burrus, LW, Byrd, DT, Caporale, N, Carpenter, EJ, Chan, YHM, Chen, L, Chovnick, A, Chu, DS, Clarkson, BK, Cooper, SE, Creech, C, Crow, KD, de la Torre, JR, Denetclaw, WF, Duncan, KE, Edwards, AS, Erickson, KL, Fuse, M, Gorga, JJ, Govindan, B, Green, LJ, Hankamp, PZ, Harris, HE, He, ZH, Ingalls, S, Ingmire, PD, Jacobs, JR, Kamakea, M, Rhea R. Kimpo, Knight, JS, Krause, SK, Krueger, LE, Light, TL, Lund, L, Márquez-Magaña, LM, McCarthy, BK, McPheron, LJ, Miller-Sims, VC, Moffatt, CA, Muick, PC, Nagami, PH, Nusse, GL, Okimura, KM, Pasion, SG, Patterson, R, Pennings, PS, Riggs, BE, Romeo, J, Roy, SW, Russo-Tait, T, Schultheis, LM, Sengupta, L, Small, R, Spicer, GS, Stillman, JH, Swei, A, Wade, JM, Waters, SB, Weinstein, SL, Willsie, JK, Wright, DW, Harrison, CD, Kelley, LA, Trujillo, G, Domingo, CD, Schinske, JN, Tanner, KD. 2017. Classroom Sound Can Be Used To Classify Teaching Practices in College Science Courses, Proceedings of the National Academy of Sciences, 114(12) 3085–3090. 

Healy Hamilton, Norah Saarman, Graham Short, Beth Moore, Tinya Hoang, Chris Grace, Martin Gomon, Karen Crow, W. Brian Simison. 2016. Molecular phylogeny and patterns of diversification in syngnathid fishes. Molecular Phylogenetics and Evolution. 107 (2017) 388-403 

Sophie Archambeault, Julia Taylor, Karen D. Crow. 2014. HoxA and HoxD expression in a variety of vertebrate body plan features reveals an ancient origin for the reverse collinear expression pattern. EvoDevo 5:44 (19 November 2014).

Sophie Archambeault, Eric Ng, Lyle Rapp, David Cerino, Bradford Bourque, Tessa Solomon-Lane, Matthew S. Grober, Andrew Rhyne, and Karen D. Crow. 2014. Reproduction, larviculture, and early development of the Bluebanded goby, Lythrypnus dalli, an emerging model organism for studies in evolutionary developmental biology and sexual plasticity. Aquaculture Research. doi:10.1111/are.12648. Online 1-5-15

John R. LaBrecque, Yvette R. Alva-Campbell, Sophie Archambeault, Karen D. Crow. 2014. Multiple paternity is a shared reproductive strategy in the live-bearing surfperches (Embiotocidae) that may be associated with female fitness. Ecology and Evolution4(12) 2316-2329.

Kelcie Chiquillo, David A. Ebert, Christina Slager, Karen D. Crow. 2014. The secret of the mermaid's purse: Phylogenetic affinities within the Rajidae and the evolution of a novel reproductive strategy in skates. Molecular Phylogenetics and Evolution. 75 (2014) 245–251.

Crow, Karen D., Christopher D. Smith, Jan-Fang Cheng, Günter P. Wagner and Chris T. Amemiya. 2012. An independent genome duplication inferred from Hox paralogs in the American paddlefish-a representative basal ray-finned fish and important comparative reference. Genome Biology and Evolution.  

Jessica M. Maxfield, James L. Van Tassell, Colette M. St. Mary, Jean-Christophe Joyeux, Karen D. Crow.  2012.  Extreme gender flexibility: Using a phylogenetic framework to infer the evolution of variation in sex allocation, phylogeography, and speciation in a genus of bidirectional sex changing fishes (Lythrypnus, Gobiidae). Molecular Phylogenetics and Evolution: 64 (2012) 416–427.

Crow, Karen D., Hiroyuki Munehara, Giacomo Bernardi.  2010. Sympatric speciation in a genus of marine reef fishes.  Molecular Ecology. 19:10 2089-2105.

Crow, Karen D., Chris Amemiya, Jutta Roth and Günter P. Wagner.  2009. Hypermutability of HoxA13a and functional divergence from its paralog are associated with the origin of a novel developmental feature in zebrafish and related taxa (Cypriniformes). Evolution.  63(6): 1574-1592.

Crow, Karen D., Hiroyuki Munehara, Ziyusei Kanamoto, Andrey Balanov, Dmitriy Antonenko, and Giacomo Bernardi.  2007.  Maintenance of species boundaries despite rampant hybridization between three species of reef fishes (Hexagrammidae): Implications for the role of selection.  Biological Journal of the Linnean Society.  91: 135-147.

Crow, Karen D. and Günter P. Wagner.  2006.  What is the role of genome duplication in the evolution of complexity and diversity in vertebrates?  Molecular Biology and Evolution.  23(5): 887-892.

Crow, Karen D., Peter F. Stadler, Vincent J. Lynch, Chris Amemiya, and Günter P. Wagner.  2006. The “fish specific” Hox cluster duplication is coincident with the origin of teleosts.  Molecular Biology and Evolution.  23(1): 121-136.

Metscher, B. D., K. Takahashi, K. D. Crow, C. Amemiya, D. F. Nonaka, and G. P. Wagner. 2005. Expression of Hoxa-11 and Hoxa-13 in the pectoral fin of a basal ray finned fish, Polyodon spathula: implications for the origin of tetrapod limbs. Evolution and Development.  7:186-195.

Crow, Karen D., Ziyusei Kanamoto and Giacomo Bernardi.  2004.  Molecular phylogeny of the hexagrammid fishes using a multi-locus approach.  Molecular Phylogenetics and Evolution.  32(3):986-997.

Balanov, A.A., A.I. Markevich, D.V. Antonenko, and K.D. Crow.  2001.  The first occurrence of hybrids of Hexagrammos otakiiH. octogrammus and description of H. otakii (Hexagrammidae) from Peter the Great Bay (Sea of Japan).  Journal of Ichthyology.  41(9):28-738. 

Nielsen, J.L., K.D. Crow and M.C. Fountain. 1999.  Microsatellite diversity and conservation of a relic trout population:  McCloud River redband trout.  Molecular Ecology.  8  (S12, Dec. 1999):129-142.

Crow, K.D., L. Barbieri and S. Lowerre-Barbieri.  1999.  "Sex, Lies, and Audiotape" or Variation in diel periodicity of courtship sound production in spotted seatrout, Cynoscion nebulosus.  Georgia Journal of Science.  57(2):143-144.

Crow, K.D., D.A. Powers and G. Bernardi.  1997.  Evidence for multiple maternal contributors in nests of kelp greenling (Hexagrammos decagrammus, Hexagrammidae).  Copeia.  1997(1):9-15.