02770nas a2200181 4500008004100000245017600041210006900217260002000286300001400306490000800320520210100328100002302429700002502452700002202477700002202499700002102521856004602542 2011 eng d00aSignal variation and its morphological correlates in Paramormyrops kingsleyae provide insight into the evolution of electrogenic signal diversity in mormyrid electric fish0 aSignal variation and its morphological correlates in Paramormyro bSpringer-Verlag a799–8170 v1973 a

We describe patterns of geographic variation in electric signal waveforms among populations of the mormyrid electric fish species Paramormyrops kingsleyae. This analysis includes study of electric organs and electric organ discharge (EOD) signals from 553 specimens collected from 12 localities in Gabon, West-Central Africa from 1998 to 2009. We measured time, slope, and voltage values from nine defined EOD “landmarks” and determined peak spectral frequencies from each waveform; these data were subjected to principal components analysis. The majority of variation in EODs is explained by two factors: the first related to EOD duration, the second related to the magnitude of the weak head-negative pre-potential, P0. Both factors varied clinally across Gabon. EODs are shorter in eastern Gabon and longer in western Gabon. Peak P0 is slightly larger in northern Gabon and smaller in southern Gabon. P0 in the EOD is due to the presence of penetrating-stalked (Pa) electrocytes in the electric organ while absence is due to the presence of non-penetrating stalked electrocytes (NPp). Across Gabon, the majority of P. kingsleyae populations surveyed have only individuals with P0-present EODs and Pa electrocytes. We discovered two geographically distinct populations, isolated from others by barriers to migration, where all individuals have P0-absent EODs with NPp electrocytes. At two sites along a boundary between P0-absent and P0-present populations, P0-absent and P0-present individuals were found in sympatry; specimens collected there had electric organs of intermediate morphology. This pattern of geographic variation in EODs is considered in the context of current phylogenetic work. Multiple independent paedomorphic losses of penetrating stalked electrocytes have occurred within five Paramormyrops species and seven genera of mormyrids. We suggest that this key anatomical feature in EOD signal evolution may be under a simple mechanism of genetic control, and may be easily influenced by selection or drift throughout the evolutionary history of mormyrids.

1 aGallant, Jason, R.1 aArnegard, Matthew, E1 aSullivan, John, P1 aCarlson, Bruce, A1 aHopkins, Carl, D uhttps://doi.org/10.1007/s00359-011-0643-801645nas a2200253 4500008004100000245006600041210006600107260005600173300001600229490000800245520086000253100002301113700002401136700002501160700002001185700001701205700002001222700002701242700001601269700002001285700001901305700001101324856005601335 2014 eng d00aGenomic basis for the convergent evolution of electric organs0 aGenomic basis for the convergent evolution of electric organs bAmerican Association for the Advancement of Science a1522–15250 v3443 a

Little is known about the genetic basis of convergent traits that originate repeatedly over broad taxonomic scales. The myogenic electric organ has evolved six times in fishes to produce electric fields used in communication, navigation, predation, or defense. We have examined the genomic basis of the convergent anatomical and physiological origins of these organs by assembling the genome of the electric eel (Electrophorus electricus) and sequencing electric organ and skeletal muscle transcriptomes from three lineages that have independently evolved electric organs. Our results indicate that, despite millions of years of evolution and large differences in the morphology of electric organ cells, independent lineages have leveraged similar transcription factors and developmental and cellular pathways in the evolution of electric organs.

1 aGallant, Jason, R.1 aTraeger, Lindsay, L1 aVolkening, Jeremy, D1 aMoffett, Howell1 aChen, Po-Hao1 aNovina, Carl, D1 aJr, George, N Phillips1 aAnand, Rene1 aWells, Gregg, B1 aPinch, Matthew1 aothers uhttps://www.science.org/doi/10.1126/science.125443201832nas a2200169 4500008004100000245008100041210006900122260001300191300001400204490000800218520128400226100002501510700002901535700002201564700002301586856005301609 2016 eng d00aElectric fish genomics: progress, prospects, and new tools for neuroethology0 aElectric fish genomics progress prospects and new tools for neur bElsevier a259–2720 v1103 a

Electric fish have served as a model system in biology since the 18th century, providing deep insight into the nature of bioelectrogenesis, the molecular structure of the synapse, and brain circuitry underlying complex behavior. Neuroethologists have collected extensive phenotypic data that span biological levels of analysis from molecules to ecosystems. This phenotypic data, together with genomic resources obtained over the past decades, have motivated new and exciting hypotheses that position the weakly electric fish model to address fundamental 21st century biological questions. This review article considers the molecular data collected for weakly electric fish over the past three decades, and the insights that data of this nature has motivated. For readers relatively new to molecular genetics techniques, we also provide a table of terminology aimed at clarifying the numerous acronyms and techniques that accompany this field. Next, we pose a research agenda for expanding genomic resources for electric fish research over the next 10 years. We conclude by considering some of the exciting research prospects for neuroethology that electric fish genomics may offer over the coming decades, if the electric fish community is successful in these endeavors.

1 aPitchers, William, R1 aConstantinou, Savvas, J.1 aLosilla, Mauricio1 aGallant, Jason, R. uhttps://doi.org/10.1016/j.jphysparis.2016.10.00301694nas a2200217 4500008004100000245006500041210006500106260001300171300001600184490000700200520103900207100001901246700002001265700001901285700002401304700001901328700001301347700002301360700002101383856007201404 2018 eng d00aElectrostatic tuning of a potassium channel in electric fish0 aElectrostatic tuning of a potassium channel in electric fish bElsevier a2094–21020 v283 a

Molecular variation contributes to the evolution of adaptive phenotypes, though it is often difficult to understand precisely how. The adaptively significant electric organ discharge behavior of weakly electric fish is the direct result of biophysical membrane properties set by ion channels. Here, we describe a voltage-gated potassium-channel gene in African electric fishes that is under positive selection and highly expressed in the electric organ. The channel produced by this gene shortens electric organ action potentials by activating quickly and at hyperpolarized membrane potentials. The source of these properties is a derived patch of negatively charged amino acids in an extracellular loop near the voltage sensor. We demonstrate that this negative patch acts by contributing to the global surface charge rather than by local interactions with specific amino acids in the channel's extracellular face. We suggest a more widespread role for this loop in the evolutionary tuning of voltage-dependent channels.

1 aSwapna, Immani1 aGhezzi, Alfredo1 aYork, Julia, M1 aMarkham, Michael, R1 aHalling, Brent1 aLu, Ying1 aGallant, Jason, R.1 aZakon, Harold, H uhttps://www.sciencedirect.com/science/article/pii/S096098221830614601755nas a2200217 4500008004100000020001400041245010500055210006900160260003900229300001400268490000800282520108300290653001601373653001801389653001301407653001701420653001201437100002501449700002301474856004001497 2024 eng d a1552-500700aA review of the reproductive biology of mormyroid fishes: An emerging model for biomedical research0 areview of the reproductive biology of mormyroid fishes An emergi bJohn Wiley & Sons, Ltdc2024/05/01 a144 - 1630 v3423 aAbstract Mormyroidea is a superfamily of weakly electric African fishes with great potential as a model in a variety of biomedical research areas including systems neuroscience, muscle cell and craniofacial development, ion channel biophysics, and flagellar/ciliary biology. However, they are currently difficult to breed in the laboratory setting, which is essential for any tractable model organism. As such, there is a need to better understand the reproductive biology of mormyroids to breed them more reliably in the laboratory to effectively use them as a biomedical research model. This review seeks to (1) briefly highlight the biomedically relevant phenotypes of mormyroids and (2) compile information about mormyroid reproduction including sex differences, breeding season, sexual maturity, gonads, gametes, and courtship/spawning behaviors. We also highlight areas of mormyroid reproductive biology that are currently unexplored and/or have the potential for further investigation that may provide insights into more successful mormyroid laboratory breeding methods.10abiomedicine10aelectric fish10amormyrid10areproduction10ateleost1 aSaunders, Alyssa, N.1 aGallant, Jason, R. uhttps://doi.org/10.1002/jez.b.23242