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Useful Xiphophorus References

Xiphophorus Genetic Stock Center Manual (First Edition)

Walter, Ronald B., Hazlewood, Leona, and Kazianis, Steven. (2006).

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The genome of the platyfish, Xiphophorus maculatus, provides insights into evolutionary adaptation and several complex traits.

Schartl M, Walter RB, Shen Y, Garcia T, Catchen J, Amores A, Braasch I, Chalopin D, Volff JN, Lesch KP, Bisazza A, Minx P, Hillier L, Wilson RK, Fuerstenberg S, Boore J, Searle S, Postlethwait JH, Warren WC. (May 2013). Nature Genetics. v45(5): pp 567-72.

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X. maculatus genome resources page

Abstract: Several attributes intuitively considered to be typical mammalian features, such as complex behavior, live birth and malignant disease such as cancer, also appeared several times independently in lower vertebrates. The genetic mechanisms underlying the evolution of these elaborate traits are poorly understood. The platyfish, X. maculatus, offers a unique model to better understand the molecular biology of such traits. We report here the sequencing of the platyfish genome. Integrating genome assembly with extensive genetic maps identified an unexpected evolutionary stability of chromosomes in fish, in contrast to in mammals. Genes associated with viviparity show signatures of positive selection, identifying new putative functional domains and rare cases of parallel evolution. We also find that genes implicated in cognition show an unexpectedly high rate of duplicate gene retention after the teleost genome duplication event, suggesting a hypothesis for the evolution of the behavioral complexity in fish, which exceeds that found in amphibians and reptiles.


Embryonic development of the platyfish (Platypoecilus), the swordtail (Xiphophorus), and their hybrids.

Tavolga, William N. (1949). Bulletin of the American Museum of Natural History. v94, article 4, pp 161-230

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De novo Transcriptome Assembly and Gene Expression Analysis using RNA-Seq from Organisms Lacking Substantial Genomic Resources.

Shen, Yingjia, Garcia, Tzintzuni, and Walter, Ronald B. (2011). In: Systems and Computational Biology - Molecular and Cellular Experimental Systems, Ning-Sun Yang (ed.), ISBN  978-953-307-280-7, INTECH publications. Janeza Trdine 9, 51000, Rijeka, Croatia, 24 pages.

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Xiphophorus Interspecies Hybrids as Genetic Models of Induced Neoplasia

Walter, Ronald B. and Kazianis, Steven. (2001). ILAR Journal. v.42(4): pp 299-321.

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Abstract: Fishes of the genus Xiphophorus (platyfishes and swordtails) are small, internally fertilizing, livebearing, and derived from freshwater habitats in Mexico, Guatemala, Belize, and Honduras. Scientists have used these fishes in cancer research studies for more than 70 yr. The genus is presently composed of 22 species that are quite divergent in their external morphology. Most cancer studies using Xiphophorus use hybrids, which can be easily produced by artificial insemination. Phenotypic traits, such as macromelanophore pigment patterns, are often drastically altered as a result of lack of gene regulation within hybrid fishes. These fish can develop large exophytic melanomas as a result of upregulated expression of these pigment patterns. Because backcross hybrid fish are susceptible to the development of melanoma and other neoplasms, they can be subjected to potentially deleterious chemical and physical agents. It is thus possible to use gene mapping and cloning methodologies to identify and characterize oncogenes and tumor suppressors implicated in spontaneous or induced neoplasia. This article reviews the history of cancer research using Xiphophorus and recent developments regarding DNA repair capabilities, mapping, and cloning of candidate genes involved in neoplastic phenotypes. The particular genetic complexity of melanoma in these fishes is analyzed and reviewed.

A Homage to Klaus Kallman: The Study of Beautiful Things

Walter, Ronald B. (2012). In: Viviparous Fishes II, M. C. Uribe and H. Grier (eds.), New Life Publications (ISBN# 0-9645058-9-1), Homestead, Fl. Pp 4-7.

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Historical Reference Papers


The Genus Xiphophorus in Mexico and Central America

Kallman, Klaus and Kazianis, Steven. (2006). Zebrafish. v3(3): 271-285.

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The Xiphophorus Genetic Stock Center

Walter, Ronald B., Kazianis, Steven, Hazlewood, Leona, Bowers, Rebecca, Kumar, Jay, Johnston, Dennis. (2005). Viviparous Fishes. New Life Publications, Homestead, Florida. p 325-331.

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Sex-Determination in Platyfishes and Swordtails

Kazianis, Steven, Vielkind, Juergen, Woolcock, Bruce, Morizot, Donald, Wigler, Michael, Lucito, Robert, Nairn, Rodney, Richards, Julie, Pedroza, Anthony, Hollek, Lori, Hazlewood, Leona, Walter, Ronald, Kallman, Klaus. (2005). Viviparous Fishes. New Life Publications, Homestead, Florida. p 381-400.

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Use of Platyfishes and Swordtails in Biological Research

Kazianis, Steven and Walter, Ronald B. (2002). Lab Animal. v31(3): 46-52.

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How the Xiphophorus Problem Arrived in San Marcos, TX

Kallman, Klaus D. (2001). Mar. Biotechnol. 3, S6-S16

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