Curriculum Vitae

Curriculum Vitae - Nicole Valenzuela



Ph.D. 1999. State University of New York at Stony Brook. Ecology and Evolution. Advisor: Dr. Charles H. Janson.

M.A. 1995. State University of New York at Stony Brook. Applied Ecology. Advisor: Dr. Charles H. Janson

B.Sc. 1991. Universidad de Los Andes, Bogotá, Colombia. Biology.

Positions Held

2017- present: Full Professor, Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University.

2010-2017: Associate Professor, Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University.

2015-2016 Visiting Associate Professor, Cytogenetics Laboratory, Genetics and Reference Center for Rare Diseases and Anomalies of Development and Malformations at the Children’s University Hospital, Dijon, France.

2004- 2010 Assistant Professor, Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University.

2009-2010 Visiting Assistant Professor, Dept. of Evolutionary Biology, Università degli Studi di Firenze, Florence, Italy.

2004- 2010 Assistant Professor, Dept. of Ecology, Evolution, and Organismal Biology, Iowa State University.

2001- 2004 Adjunct Assistant Professor and Associate Scientist, Dept. of Zoology and Genetics / EEOB, Iowa State University, Ames, Iowa.

2000-2001 Affiliate Assistant Professor, Dept. of Zoology and Genetics, Iowa State University.

1999-2000 Postdoctoral Associate, Dept. of Zoology and Genetics, Dr. Fredric Janzen, Iowa State University.

2003-2013 Faculty Member, Center for Integrative Animal Genomics, Iowa State University.

2001- present: Faculty Member, Interdepartmental Programs in Ecology and Evolutionary Biology (EEB), Genetics (IG), and Bioinformatics and Computational Biology (BCB) & Multidisciplicary Graduate Education Training (MGET), Iowa State University.

Awards, Honors and Scholarships

2021 Elected Fellow, American Association for the Advancement of Science (AAAS).

2015 Mid-Career Achievement in Research Award, College of Liberal Arts and Sciences, Iowa State University.

2004 National Society of Collegiate Scholars Faculty of the Year Student Nominee.

1997 Department of Ecology and Evolution, SUNY at Stony Brook. Outstanding Graduate Student Presentation Award.

1995 Fulbright Commission. Exceptional Research Award.

1993 Fulbright Commission, Amazon Basin Program. Scholarship.

1986 José Antonio Galán Fund, Colombia. Scholarship. 1986 ICETEX, Colombia. Scholarship

External Grants

2021-2025 National Science Foundation – Enabling Discovery through GEnomics IOS 2127995– “EDGE FGT: Development of fibroblasts and organoids as tools for functional genomics in turtles, applicable to other non-mammalian vertebrates”

2021 • NSF Supplement (IOS 2129793) to IOS 1555999

2016-2020 National Science Foundation – Evolution of Developmental Mechanisms IOS 1555999– “Evolution of Dosage Compensation - An empirical test using turtles with independently evolved XX/XY and ZZ/ZW chromosomes”

2013-2016 National Science Foundation – Eukaryotic Genetics MCB 1244355– “Genome repatterning underlying the co-evolution of diploid number and sex determination in turtles”

2013-2015 National Science Foundation – DEB 1310793– DISSERTATION RESEARCH: The genome-wide occupancy and thermosensitivity of histone variant H2A.Z in embryonic Chrysemys picta, a turtle with temperature-dependent sex determination. (Co-PI: R. Literman).

2009-2011 Colciencias (Colombia’s National Science Foundation) – “Maternal and paternal effects on hatchling sex ratio and fitness in the riverine turtle Podocnemis lewyana”. Co-PI with Grupo Herpetológico de Antioquia, Colombia.

2009-2012 National Science Foundation – Eukaryotic Genetics MCB 0815354 “COLLABORATIVE RESEARCH: Sex Chromosome Evolution in Turtles” PI: N. Valenzuela, CoPI: S.V. Edwards (Harvard University).
2011 • NSF REU supplement (MCB 1112116)
2012 • NSF REU supplement (MCB 1233241)
2012 • NSF Supplement (MCB 1233234)

2008-2011 National Science Foundation – Developmental Systems IOS 0743284 “Gene expression response to naturally fluctuating temperature in turtles with alternative sex determining mechanisms”
2008 • NSF RET supplement (IOS 0824550)
2008 • NSF REU supplement (IOS 0826664)
2009 • NSF RET supplement (IOS 0924290)
2009 • NSF REU supplement (IOS 0925486)
2010 • NSF RET supplement (IOS 1032265)

2008-2011 National Science Foundation – Evolutionary Genetics DEB 0808047 “DISSERTATION RESEARCH: Phenotypic plasticity, sexual size dimorphism and Rensch's rule in freshwater turtles” (Co-PI: C. Ceballos)

2008-2009 National Science Foundation – Organism-Environment Interactions IOS 0809547 “Symposium: Reptile genomics and evolutionary genetics”. (Co-Organizers: D.E. Janes, C.L. Organ).

2006-2007 Turtle Conservation Fund – “Environmental effects on fitness of embryos and hatchlings of the endangered Arrau River Turtle, Podocnemis expansa, with important conservation implications”, CoPI with C. Ceballos.

2006-2007 Scott Neotropical Fund, Cleveland Zoo – “Metapopulation Genetics of the freshwater turtle Podocnemis unifilis”, Co-PI with T. Escalona

2003-2004 Lincoln Park Zoo –“Effect of nest transplant on hatchling sex and viability: an evaluation of conservation practices for the giant river turtle (Podocnemis expansa) in Venezuela” (Co-P.I., with C. Peñaloza and G. Barreto).

1998-2000 National Science Foundation. – Ecological & Evolutionary Physiology IOS 9800679 “Dissertation Research: Temperature-dependent sex determination in Podocnemis expansa”. (PI: C. Janson).

1996-1998 Colciencias (Colombia’s National Science Foundation) – “Temperature-dependent sex determination and population structure of Podocnemis expansafrom Colombian Amazonia”.

1996-1998 PADI Foundation. –“Determination of Multiple Paternity in the Giant River Turtle Podocnemis expansa”.

Teaching Experience

2018- present (every year) Evolution (Biol 315), Iowa State University

2018- present (every odd year) Herpetology (Biol/AEcl 457), Iowa State University

2018- present (every even year) Conceptual Foundations in Ecology and Evolutionary Biology (EEB 511), Iowa State University

2014-2018 Life Histories and reproduction (EEOB 514 / Biol 414), Iowa State University

2015- 2017 Introductory Biology (Biol 101), Iowa State University

2011 Graduate Seminar (EEOB 590B) Extended Evolutionary Synthesis, Iowa State University

2010 Undergraduate Seminar (Biol 495) Evolutionary Ecology of Sex, Iowa State University

2008, 2009, 2012, 2013, 2018 Honors Research (HON 280H VM), Iowa State University

2007 Biology Internship (Biol 494), Iowa State University

2007-present: Individual Student Biology Research (Biol 490R), Iowa State University

2008- present: EEB Graduate Research (Genet 699), Iowa State University

2005- present: EEB Graduate Research (EEB 699), Iowa State University

2007 Graduate Seminar, Evolutionary Ecology of Sex (EEOB 590B), Iowa State University

2006, 2008, 2012 Evolutionary Ecology (EEOB 514), Iowa State University

2004-2014 (every year) Environmental Biology (Biol 173, former Biol 123), Iowa State University

2000- 2001 Undergraduate Mentoring in Environmental Biology Seminar (program sponsored by NSF), Dept. of Zoology and Genetics, Iowa State University.

1999-2000 General Biology Laboratory, Dept. of Zoology and Genetics, Iowa State University.

1997-1998 Teaching Assistant: General Ecology, Ecology Laboratory, Ecology. Dept. of Ecology and Evolution, SUNY at Stony Brook, New York.

1995 Teaching Assistant: General Ecology, Lab instructor of Cat Anatomy, Elementary Organismic Biology. Dept. of Ecology and Evolution, SUNY at Stony Brook, NY

1991 Laboratory Instructor: Genetics. Universidad de Los Andes, Colombia.


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100.  Zdyrski C, Vojtech G, Gessler TB, Ralston A, Sifuentes-Romero I, Kundu D, Honold, S, Wickham H, Topping N, Sahoo DK, Bista B, Tamplin J, Ospina O, Piñeyro P, Arriaga M, Galan JA, Meyerholz DK, Allenspach K, Mochel JP, and Valenzuela N. 2024. Establishment and Characterization of Turtle Liver Organoids Provides a Potential Model to Decode their Unique Adaptations. Communications Biology, 7 (1): 218. DOI 10.1038/s42003-024-05818-1. 

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99. Topping N and Valenzuela N. 2023. Thermal response of circulating estrogens in an Emydid turtle, Chrysemys picta, and the challenges of climate change. Diversity 15, 428.

98. Gessler TB, Wu Z, Valenzuela N. 2023. Transcriptomic thermal plasticity underlying gonadal development in a turtle with ZZ/ZW sex chromosomes despite canalized genotypic sex determination. Ecology and Evolution 13, e9854. 

97. Mizoguchi B.A. and Valenzuela N. 2023. A cautionary tale of sexing by methylation: Hybrid bisulfite-conversion sequencing of immunoprecipitated methylated DNA in Chrysemys picta turtles with temperature-dependent sex determination reveals contrasting patterns of somatic and gonadal methylation. Animals 13 (1), 117. 


96. Marín-Gual L, González-Rodelas L, Garcias MM, Kratochvil L, Valenzuela N, Georges A, Waters PD, Ruiz-Herrera A. 2022. Meiotic chromosome dynamics and double strand break formation in reptiles. Frontiers in Cell and Developmental Biology 10:1009776.

95. Mizoguchi1 B, Topping NE, Lavin AM and Valenzuela N. 2022. Cadmium ecotoxic effects on embryonic Dmrt1 and aromatase expression in Chrysemys picta turtles may implicate changes in DNA methylation. Genes. 13, 1318.

94. Camillo CS, Valenzuela N, Johnson SA. Effects of constant temperature on embryonic development of six-tubercled Amazon River turtles, Podocnemis sextuberculataJournal of Thermal Biology 108, 103292.

93. Montiel EE, Badenhorst D, Lee LS, Valenzuela N. Evolution and dosage compensation of nucleolar organizing regions (NORs) mediated by mobile elements in turtles with female (ZZ/ZW) but not with male (XX/XY) heterogamety. Journal of Evolutionary Biology. DOI: 10.1111/jeb.14064.

92. Bronikowski AM, Meisel RP, Biga PR, Walters JR, Mank JE, Larschan E, Wilkinson GS, Valenzuela N, Conard AM, Magalhães JP,  Duan J , Elias AE, Gamble T, Graze RM, Gribble KE, Kreiling JA, and Riddle NC. 2022. Sex-specific aging in animals: Perspective and future directions. Aging Cell. 21: e13542.


91. Topping N and Valenzuela N. 2021. Turtle nest-site choice, anthropogenic challenges, and evolutionary potential for adaptation. Frontiers in Ecology & Evolution 9: 808621.

90. Valenzuela N and Schartl M. 2021. Preface to Special Issue on Sexual Development and the Environment. Sexual Development. DOI: 10.1159/000517937.

89. Kratochvíl L, Stöck L, Rovatsos M, Bullejos M, Herpin A, Jeffries DL, Peichel CL, Perrin N, Valenzuela N, Pokorná MJ. 2021. Expanding the classical paradigm: what we have learnt from vertebrates about sex chromosome evolution. Philosophical Transactions of the Royal Society B. 376: 20200097. 

88. Stöck M, Kratochvíl L, Kuhl H, Rovatsos M, Evans B, Suh A, Valenzuela N, Veyrunes F,  Zhou Q, Gamble T, Capel B, Schartl M, Guiguen Y. 2021. A brief review of vertebrate sex evolution with a pledge for integrative research - towards ‘sexomics’. Philosophical Transactions of the Royal Society B.  376: 20200426.

87.  Bista B, Wu Z, Literman R, and Valenzuela N. 2021. Thermosensitive sex chromosome dosage compensation in ZZ/ZW softshell turtles, Apalone spinifera. Philosophical Transactions of the Royal Society. DOI: 10.1098/rstb.2020.0101

86. Valenzuela N. 2021. Podocnemis expansa turtles hint to a unifying explanation for the evolution of temperature dependent sex determination in long-lived and short-lived vertebrates. Sexual Development. DOI: 10.1159/000515208. 


85. Gemmell, N.J., Rutherford, K., Prost, S., Tollis, M., Winter, D., Macey, J.R., Adelson, D.L., Suh, A., Bertozzi, T., Grau, J.H., Organ, C., Gardner, P.P., Muffato, M., Patricio, M., Billis, K., Martin, F.J., Flicek, P., Petersen, B., Kang, L., Michalak, P., Buckley, T.R., Wilson, M., Cheng, Y., Miller, H., Schott, R.K., Jordan, M.D., Newcomb, R.D., Arroyo, J.I., Valenzuela, N., Hore, T.A., Renart, J., Peona, V., Peart, C.R., Warmuth, V.M., Zeng, L., Kortschak, R.D., Raison, J.M., Zapata, V.V., Wu, Z., Santesmasses, D., Mariotti, M., Guigó, R., Rupp, S.M., Twort, V.G., Dussex, N., Taylor, H., Abe, H., Bond, D.M., Paterson, J.M., Mulcahy, D.G., Gonzalez, V.L., Barbieri, C.G., DeMeo, D.P., Pabinger, S., Van Stijn, T., Clarke, S., Ryder, O., Edwards, S.V., Salzberg, S.L., Anderson, L., Nelson, N., Stone, C., Stone, C., Smillie, J., Edmonds, H., Ngatiwai Trust, B., 2020. The tuatara genome reveals ancient features of amniote evolution. Nature. DOI: 10.1038/s41586-020-2561-9. 

84. Lee LS, Navarro-Domínguez BM, Wu Z, Montiel EE, Badenhorst D, Bista B, Gessler TB, and Valenzuela N. 2020. Karyotypic evolution of sauropsid vertebrates illuminated by optical and physical mapping of the painted turtle and slider turtle genomes. Genes, 11, 928, doi:10.3390/genes11080928.

83. Bista B. and Valenzuela N. 2020. Turtle insights into the evolution of the reptilian karyotype and the genomic architecture of sex determination. Genes 11 (4): 416. DOI 10.3390/genes11040416.

82. Mizoguchi B.A. and Valenzuela N. 2020. Alternative splicing and thermosensitive expression of Dmrt1 during urogenital development in the painted turtle, Chrysemys picta. PeerJ. 8:e8639.


81. Escalona T, Valenzuela N, and Adams DC. 2019. Do local environmental factors and lunar cycle influence timing and synchrony of oviposition of a turtle with strict nocturnal nesting? Diversity 11: 78; DOI:10.3390/d11050078. 

80. Lee LS, Montiel EE, and Valenzuela N. 2019. Discovery of putative XX/XY male heterogamety in Emydura subglobosa turtles exposes a novel trajectory of sex chromosome evolution in Emydura. Cytogenetic and Genome Research 158:160–169. 

79. Valenzuela N, R Literman, JL Neuwald, BA Mizoguchi, JB Iverson, JL Riley, and JD Litzgus. 2019. Extreme thermal fluctuations from climate change unexpectedly accelerate demographic collapse of vertebrates with temperature-dependent sex determination Scientific Reports )9 (4254.​​​​​ DOI: 10.1038/s41598-019-40597-4. 

78. Lee LS, EE Montiel, BM Navarro-Domínguez, and N Valenzuela. 2019. Chromosomal Rearrangements During Turtle Evolution Altered the Synteny of Genes Involved in Vertebrate Sex Determination. Cytogenetic and Genome Research 157:77-88. 


77. Radhakrishnan S, Literman R, Neuwald JL, and N Valenzuela. 2018. Thermal response of epigenetic genes informs turtle sex determination with and without sex chromosomes Sexual Development. DOI: 10.1159/000492188 . 

76. O’Connor, RE, Romanov MN, Kiazim L, Barrett PM, Farré M, Damas J, Ferguson-Smith M, Valenzuela N, Larkin DM, Griffin DK. 2018. Reconstruction of genome organization in the diapsid common ancestor permits tracing of chromosome evolution in avian and non-avian dinosaurs. Nature Communications 9:1883.

75. Literman R, Burrett A, Bista B, and Valenzuela N. 2018. Putative independent evolutionary reversals from genotypic to temperature-dependent sex determination are associated with accelerated evolution of sex-determining genes in turtles. Journal of Molecular Evolution 86:11–26. 

74. Escalona T, Valenzuela N, Adams DC. 2018. A lengthy solution to the optimal propagule size problem in the large-bodied South American freshwater turtle, Podocnemis unifilisEvolutionary Ecology 32:29–41.

73. Valenzuela, N. 2018. Causes and consequences of evolutionary transitions in the level of phenotypic plasticity of reptilian sex determination. In Plasticity of Sexual Systems. J. Leonard, Editor. Springer. In press.


72. Radhakrishnan S and Valenzuela N. 2017. Chromosomal context affects the molecular evolution of sex-linked genes and their autosomal counterparts in turtles and other vertebrates. Journal of Heredity 108:720-730. 

71. Tang WQ, Mu Y, Valenzuela N, Du WD. Effects of incubation temperature on the expression of sex-related genes in the Chinese pond turtle, Mauremys reevesii.Sexual Development.

70. Radhakrishnan S, Literman R, Mizoguchi B, and Valenzuela N. 2017. MeDIPseq and nCpG analyses illuminate sexually dimorphic methylation of gonadal development genes with high historic methylation in turtle hatchlings with temperature-dependent sex determination.Epigenetics & Chromatin 10:28. DOI 10.1186/s13072-017-0136-2.

69. Literman R., S. Radhakrishnan, J. Tamplin, R. Burke, C. Dresser, and Valenzuela N. 2017. Development of sexing markers in Glyptemys insculpta and Apalone spinifera turtles uncovers an XX/XY sex-determining system in the critically-endangered bog turtle Glyptemys muhlenbergii.Conservation Genetic Resources. DOI 10.1007/s12686-017-0711-7. 

68. Radhakrishnan S, R Literman, J Neuwald, A Severin, and Valenzuela N. Transcriptomic responses to environmental temperature by turtles with temperature-dependent and genotypic sex determination assessed by RNAseq inform the genetic architecture of embryonic gonadal development. 2017. PLoS ONE12(3): e0172044. 

67 Montiel EE, D Badenhorst, J Tamplin, R Burke, and N Valenzuela. 2017. Discovery of youngest sex chromosomes reveals first case of convergent co-option of ancestral autosomes in turtles. Chromosoma 126:105–113. 


66. Twyman H, Valenzuela N, Literman R, Andersson S, Mundy NI. 2016. Seeing red to being red: conserved genetic mechanism for red cone oil droplets and co-option for red coloration in birds and turtles.Proceedings of The Royal Society B. 283: 20161208. 

65. Sabath N, Itescu Y, Feldman A, Meiri S., Mayrose I., and N Valenzuela. 2016. Sex determination and the birth and death of species. Ecology and Evolution . DOI 10.1002/ece3.2277. 

64. Montiel EE, D Badenhorst, LS Lee, R Literman, V Trifonov, N Valenzuela. 2016. Cytogenetic insights into the evolution of chromosomes and sex determination reveal striking homology of turtle sex chromosomes to amphibian autosomes. Cytogenetic and Genome Research 148:292-304.

63. Mizoguchi BA and N Valenzuela. 2016. Ecotoxicological perspectives of sex determination. Sexual Development 10:45-57. DOI:10.1159/000444770.

62. Gómez-Saldarriaga C, N Valenzuela, and C.P. Ceballos. 2016. Effects of the incubation temperature on the onset and duration of the thermosensitive period for sex determination in the Magdalena River Turtle, Podocnemis lewyanaChelonian Conservation and Biology 15 (1): 43-53.


61. Badenhorst D, LD Hillier, R Literman, EE Montiel, S Radhakrishnan, P Minx, DE Janes, WC Warren, SV Edwards, and N Valenzuela. 2015. Physical mapping and refinement of the painted turtle genome (Chrysemys picta) inform amniote genome evolution and challenges turtle-bird chromosomal conservation. Genome Biology and Evolution 7(7):2038–2050. 

60. Pennell M, Kirkpatrick M, Otto S, Vamosi J, Peichel C, Valenzuela N, Kitano J. 2015. Y fuse? Sex chromosome fusions in fishes and reptiles. PLoS Genetics11(5): e100523.

59. Mu Y., Zhao B., Tang W., Sun B., Zeng Z., Valenzuela N., Du W. 2015. Temperature-dependent sex determination ruled out in the Chinese soft-shelled turtle (Pelodiscus sinensis) via molecular cytogenetics and incubation experiments across populations. Sexual Development 9:111-117. 


58. Janes DE, Organ CL, Stiglec R, O’Meally D, Sarre SD, Georges A, Graves JAM, Valenzuela N, Literman R, Rutherford K, Gemmell N, Iverson JB, Tamplin JW, Edwards SV, Ezaz T. Molecular evolution of Dmrt1 accompanies change of sex-determining mechanisms in Reptilia. Biology Letters 10: 20140809. 

57. Literman R, D Badenhorst, and N Valenzuela. 2014. QPCR-based molecular sexing by copy number variation in rRNA genes and its utility for sex identification in soft-shell turtles. Methods in Ecology and Evolution 5: 872-880. 

56. The Tree of Sex Consortium 2014. TL Ashman, D Bachtrog, H Blackmon, EE Goldberg, MW Hahn, M Kirkpatrick, J Kitano, JE Mank, I Mayrose, R Ming, SP Otto , CL Peichel, MW Pennell, N Perrin, L Ross, N Valenzuela, JC Vamosi. Tree of Sex: A database of sexual systems. Nature Scientific Data 1:140015. DOI: 10.1038/sdata.2014.15. 

55. Valenzuela N, D Badenhorst, EE Montiel, R. Literman. 2014. Molecular cytogenetic search for cryptic sex chromosomes in painted turtles Chrysemys pictaCytogenetic and Genome Research 144: 39-46. 

54. The Tree of Sex Consortium: Bachtrog D, Mank JE, Peichel CL, Kirkpatrick M, Otto S, Ashman TL, Hahn M, Kitano J, Mayrose I, Ming R, Perrin N, Ross L, N Valenzuela, Vamosi J. 2014. Sex determination: Why so many ways of doing it? PLoS Biology 12(7): e1001899. doi:10.1371/journal.pbio.1001899. 

53. Ceballos CP, OE Hernández and N Valenzuela. 2014. Divergent sex-specific plasticity in long-lived vertebrates with contrasting sexual dimorphism. Evolutionary Biology 41:81–98. 


52. Weiner SA, DA Galbraith, DC Adams, N Valenzuela, FB Noll, CM Grozinger, and AL Toth. 2013. A survey of DNA methylation across social insect species, life stages, and castes reveals abundant and caste-associated methylation in a primitively social wasp. Naturwissenschaften 100: 795-799.

51. Shaffer HB, P Minx, DE Warren, AM Shedlock, RC Thomson, N Valenzuela, J Abramyan, D Badenhorst, KK Biggar, GM Borchert, CW Botka, RM Bowden, EL Braun, AM Bronikowski, BG Bruneau, LT Buck, B Capel, TA Castoe, M Czerwinski, KD Delehaunty, SW Edwards, CC Fronick, MK Fujita, L Fulton, TA Graves-Lindsey, RE Green, W Haerty, R Hariharan, LW Hillier, AK Holloway, D Janes, FJ Janzen, C Kandoth, L Kong, APJ de Koning, Y Li, R Literman, SE McGaugh, L Mork, M O’Laughlin, RT Paitz, DD Pollock, CP Ponting, S Radhakrishnan, BJ Raney, JM Richman, J StJohn, T Schwartz, A Sethuraman, PQ Spinks, KB Storey, N Thane, T Vinar, LM Zimmerman, WC Warren, ER Mardis, and RK Wilson. 2013. The western painted turtle genome, a model for the evolution of extreme physiological adaptations in a slowly evolving lineage. Genome Biology. DOI:10.1186/gb-2013-14-3-r28.

50. Janes DE, Elsey RM, Langan EM, Moore B, Edwards SV and N Valenzuela. 2013. Sex-biased expression of sex-differentiating genes Foxl2 and Fgf9 in American alligators, Alligator mississippiensisSexual Development. 7: 253–260.

49. Badenhorst, D., R. Stanyon, T. Engstrom, and N. Valenzuela.2013. A ZZ/ZW microchromosome system in the spiny softshell turtle, Apalone spinifera reveals an intriguing sex chromosome conservation in Trionychidae. Chromosome Research. 12(2): 137-147. DOI 10.1007/s10577-013-9343-2. 

48. Valenzuela N., J. Neuwald, and R. Literman. 2013. Transcriptional evolution underlying vertebrate sexual development. Developmental Dynamics. 242:307–319. DOI: 10.1002/dvdy.23897.

47. Ceballos C.P., Adams D.C., Iverson J.B., and Valenzuela N. 2013. Phylogenetic patterns of sexual size dimorphism in turtles and their implications for Rensch´s rule. Evolutionary Biology 40: 194-208. DOI: 10.1007/s11692-012-9199-y. 


46. Valenzuela N. and Ceballos C.P. 2012. Evolución y mecanismos de determinación sexual en tortugas. In: Biología y Conservación de las Tortugas Continentales de Colombia. Paez V.P. Editor. Serie Editorial “Recursos Hidrobiológicos y Pesqueros de Colombia”, Instituto de Investigación de Recursos Biológicos Alexander von Humboldt, Bogotá, Colombia. 


45. Bachtrog D., Kirkpatrick M, Mank, J.E., McDaniel S.F., Pires J.C., Rice W. and Valenzuela N. 2011. Are all sex chromosomes created equal? Trends in Genetics 27 (9): 350-357.

44. Ceballos, C. and Valenzuela, N. The role of sex-specific plasticity in shaping sexual dimorphism in a long-lived vertebrate, the snapping turtle Chelydra serpentina. Evolutionary Biology 38: 163-181.

43. Neuwald J.L. and Valenzuela N. 2011. The Lesser Known Challenge of Climate Change: Thermal Variance and Sex-Reversal in Vertebrates with Temperature-Dependent Sex Determination PloS ONE 6(3): e18117. doi:10.1371/journal.pone.0018117.

42. Valenzuela N. and Adams D.C. 2011. Chromosome number and sex determination co-evolve in turtles Evolution 65: 1808-1813.

41. Janes, D.E., Valenzuela N., Ezaz T., Amemiya C., and Edwards S.V. 2011. Sex chromosome evolution in Amniotes: applications for bacterial artificial chromosome libraries. Journal of Biomedicine and Biotechnology Vol 2011, doi:10.1155/2011/132975.


40. Valenzuela, N. 2010. Co-evolution of genomic structure and selective forces underlying sexual development and reproduction. Cytogenetics nd Genome Research 127:232–241.

39. Valenzuela, N. 2010. Multivariate expression analysis of the gene network underlying sexual development in turtle embryos with temperature-dependent and genotypic sex determination. Sexual Development 4 (1-2): 39-49. 


38. Valenzuela, N. 2009. The painted turtle, Chrysemys picta: A model system for vertebrate evolution, ecology, and human health. Cold Spring Harbor Protocols2009: DOI:10.1101/pdb.emo124.

37. Valenzuela, N. 2009. Egg incubation and collection of painted turtle embryos. Cold Spring Harbor Protocols 2009 DOI:10.1101/pdb.prot5238. 

36. Escalona, T., Adams, D.C., and Valenzuela, N. 2009. Nesting ecology in the freshwater turtle Podocnemis unifilis: spatiotemporal patterns and inferred explanations. Functional Ecology 23: 826-835. 

35. Escalona, T., Engstrom T.N., Hernandez O.E., Bock B.C., Vogt R.C. and Valenzuela N. 2009. Population genetics of the endangered South American freshwater turtle, Podocnemis unifilis, inferred from microsatellite DNA data. Conservation Genetics 10: 1683–1696.


34. Chinsamy, A. and Valenzuela, N. 2008. Skeletochronology of the endangered side-neck turtles Podocnemis expansaSouth African Journal of Science104(7/8): 311-314. 

33. Martinez, P., Ezaz T., Valenzuela, N., Georges, A., and Graves J.A.M. 2008. An XX/XY heteromorphic sex chromosome system in the Australian chelid turtle Emydura macquarii, a new piece in the puzzle of sex chromosome evolution in turtles. Chromosome Research 16(6): 815-825. 

32. Valenzuela, N. 2008. Sexual development and the evolution of sex determination. Sexual Development 2(2): 64-72.

31. Valenzuela, N. 2008. Evolution of the gene network underlying gonadogenesis in turtles with temperature-dependent and genotypic sex determination. Integrative and Comparative Biology 48 (4): 476-485. 

30. Janes D.E., Organ C., and Valenzuela N. 2008. New resources inform study of genome size, content and organization in non-avian reptiles. Integrative and Comparative Biology 48(4): 447-453. 

29. Valenzuela, N. 2008. Relic thermosensitive gene expression in a turtle with genotypic sex determination. Evolution 62-1: 234-240.


28. McGaugh, S.E., Alacs E.A., Edwards S.V., Feldman C.R., Georges A., Sites, J.R.Jr., Valenzuela N. 2007. From molecules to organisms: Research applications of modern genetic tools for turtle biology and conservation. Chelonian Research Monographs 4: 47-72. 

27. Valenzuela, N. and Shikano T. 2007. Embryological ontogeny of Aromatase gene expression in Chrysemys picta and Apalone mutica turtles: comparative patterns within and across temperature-dependent and genotypic sex-determining mechanisms. Development, Genes and Evolution 217: 55–62. 


26. Valenzuela, N., LeClere A., and Shikano T. 2006. Comparative expression of steroidogenic factor 1 in Chrysemys picta and Apalone mutica turtles with environmental and genotypic sex determination. Evolution and Development 8 (5): 424-432.

25. Ezaz T., Valenzuela, N., Gruetzner F., Miura I., Burke R., Georges, A. and Graves J.M. 2006. An XX/XY sex microchromosome system in a freshwater turtle, Chelodina longicollis (Testudines : Chelidae) with genetic sex determination. Chromosome Research 14:139-150. 

24. Pearse, D.E., A.D. Arndt, N. Valenzuela, B.A. Miller, V. Cantarelli, J.W. Sites, Jr. 2006. Estimating population structure under non-equilibrium conditions in a conservation context: Continent-wide population genetics of the giant Amazon river turtle Podocnemis expansa (Chelonia; Podocnemidae). Molecular Ecology 15: 985-1006.  

23. Valenzuela, N. 2006. (Book Review). Incubation of Reptile Eggs: Basics, Guidelines, Experiences, by Gunther Kohler. Quarterly Review of Biology 81:290-291.


22. BOOK: Valenzuela, N. and V. Lance, Eds. 2004. Temperature Dependent Sex Determination in Vertebrates. Smithsonian Books. Washington D.C.

19. Valenzuela, N. 2004. Temperature-dependent sex determination. Pp. 211-227. In Deeming D.C. Ed. Reptilian Incubation: Environment & Behaviour. Nottingham University Press.


18. Valenzuela, N., D.C. Adams, and F.J. Janzen. 2003. Pattern does not equal process: Exactly when is sex environmentally determined? American Naturalist161 (4): 676-683.  

17. Kagima, B. W., N. Valenzuela, T. Engstrom, B. Bock. 2003. Preliminary population genetic study of the yellow spotted Amazon river turtle (Podocnemis unifilis) using microsatellite DNA data. Integrative and Comparative Biology 43: 1025-1025.


16. Milne-Morjan, C. and N. Valenzuela. 2001. Is ground-nuzzling by female turtles associated with soil surface temperatures? Journal of Herpetology 35(4): 668-672  

15. Valenzuela, N. and F. J. Janzen. 2001. Nest-site philopatry and the evolution of temperature-dependent sex determination. Evolutionary Ecology Research 3: 779-794. 

14. Valenzuela, N. 2001. Constant, shift and natural temperature effects on sex determination in Podocnemis expansa turtles. Ecology 82(11): 3010–3024.  

13. Valenzuela, N. 2001. Maternal effects on life history traits in the Amazonian giant river turtle Podocnemis expansaJournal of Herpetology 35(3): 368-378. 

12. Valenzuela, N. 2001. Genetic differentiation among nesting beaches in the highly migratory giant river turtle (Podocnemis expansa) from Colombia.Herpetologica 57(1): 48-57.  


11. Valenzuela, N. 2000. Multiple paternity in side-neck turtles Podocnemis expansa: evidence from microsatellite DNA data. Molecular Ecology 9: 99-106. 


10. Adams, D. C., M. S. Di Bitetti, C. H. Janson, L. B. Slobodkin, and N. Valenzuela. 1997.  An “audience effect” for ecological terminology: use and misuse of jargon. Oikos 80:632-636. 

9. Valenzuela, N, E. Martínez, and R. Botero.  1997. Field study of sex determination in Podocnemis expansa from Colombian Amazonia. Herpetologica 53(3):390-398.   


8. Valenzuela, N, E. Martínez, and R. Botero. 1995. Preliminary model of sex determination of Podocnemis expansa from Colombian Amazonia. Proceedings of the International Congress of Chelonian Conservation and Biology. Pp. 276-278.


7. Lance,V.A., N. Valenzuela and P. von Hildebrand. 1992. A hormonal method to determine the sex of hatchling giant river turtles, Podocnemis expansa. Application to endangered species research. American Zoologist 32:16A. 


Undergraduate work (1990-1994)

6. Valenzuela, N. 1994. Early behavioral development of three wild infant Cebus apella in Colombia.  Selected Proceedings of the XIVth Congress of the International Primatological Society, Strasbourg, France, 1992. Current Primatology, Volume II. Social Development, Learning and Behaviour. (Roeder, J.J., Thierry, B., Anderson, J.R. and N. Herrenschmidt, eds.). Pp. 297-302. 

5. Valenzuela, N. 1993. Social contacts between infants and other group members in the wild Cebus apellaField Studies of New World Monkeys at La Macarena, Colombia 8: 1-9. 

4. Valenzuela, N. 1992. Early development of three wild infant Cebus apella at La Macarena, Colombia. Field Studies of New World Monkeys at La Macarena,Colombia 6: 15-23. 

3. Espinel A. and N. Valenzuela. 1991. Adaptaciones genéticas a la malaria en poblaciones afroaborígenes del Pacífico Colombiano. Revista de Antropología y Arqueología. 7:117-130. 

2. Groot de Restrepo, H., A. Espinel, N. Valenzuela, D. Sicard, P. Angulo, and D. Nieto. 1991. Variabilidad Genética en el Género Cebus en Colombia. Proceedings of the II Congreso de PrimatologíaBarranquilla, Colombia.

1. Espinel A., N. Valenzuela, A. Fajardo, J. Umaña, and G. Quintero. 1990. Breve reseña de las actividades primatológicas en Colombia. Boletín Primatología Latinoamericana 2(1):62-68.


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