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Kowalko, Johanna Elizabeth

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Kowalko

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Johanna Elizabeth

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Kowalko, Johanna Elizabeth

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    Loss of Schooling Behavior in Cavefish through Sight-Dependent and Sight-Independent Mechanisms
    (Elsevier BV, 2013) Kowalko, Johanna Elizabeth; Rohner, Nicolas; Rompani, Santiago B.; Peterson, Brant K.; Linden, Tess; Yoshizawa, Masato; Kay, Emily H.; Weber, Jesse; Hoekstra, Hopi; Jeffery, William R.; Borowsky, Richard; Tabin, Clifford
    Background: Surface populations of Astyanax mexicanus, living in rivers like their common ancestors, school, while several, independently derived cave populations of the same species have lost schooling behavior.Results: We quantify schooling behavior in individual A. mexicanus and identify quantitative trait loci (QTL) for this trait. We find that the evolutionary modulation of schooling has both vision-dependent and -independent components. We also quantify differences in the lateral line and vision between cavefish and surface fish and relate these differences to the evolutionary loss of schooling behavior. We provide evidence that a monoamine neurotransmitter may have played a role in the evolution of schooling behavior. Conclusions: We find that vision is essential for schooling tendency in A. mexicanus, while the lateral line has a small effect on this behavior. Schooling behavior in A. mexicanus has evolved both through changes in sensory systems and through changes in genetic loci that likely act downstream of sensory inputs.
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    The genetic basis of behavior in the blind Mexican cavefish, Astyanax mexicanus
    (2013-10-18) Kowalko, Johanna Elizabeth; Tabin, Clifford James; Drummond, Iain; Hanken, James; Garrity, Paul; Harris, Matthew
    In recent years, considerable progress has been made towards understanding the genetic basis of the evolution of morphological traits. In contrast, relatively little is known about how behavioral traits evolve. Astyanax mexicanus, a species of fish that exists in both surface and cave forms, is an ideal system to study behavioral evolution. Surface and cave morphs of Astyanax mexicanus differ in a variety of morphological and behavioral traits. They are interfertile, allowing for genetic analysis of the evolution of these traits. Finally, Astyanax mexicanus exists in multiple, independently evolved cave populations, providing an excellent system for studying convergent evolution.