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Dan Janes


Department of Organismic and Evolutionary Biology,
Harvard University,
26 Oxford Street,
Cambridge, MA 02138

MCZ Labs Room 301
Tel: 617-496-2375
Fax: 617-495-5667

email: djanes(at)




Ph.D.: University of Florida; Zoology, 2004
M.S.: University of Memphis; Vertebrate Biology; 1999
Ed.M.: Boston University; Teaching and Curriculum Design; 1998
B.A.: Boston University; Biology; 1996

Research Interests:

I am an evolutionary geneticist with interests in sex-determining mechanisms and sex chromosomes. My graduate work described genetic and environmental influences on sex determination in the Leopard Gecko, an environmentally sex-determined reptile. I am fascinated by the seemingly haphazard variation in sex determining mechanisms among reptiles. This variation suggests that genetic and environmental sex determination have evolved repeatedly over relatively short periods of time. My postdoctoral work focuses on sex chromosomes. Sex chromosomes represent exceptions to many rules regarding molecular evolution. The benefits of recombination, and therefore sex, can be elucidated by describing the detriments of a lack of recombination as can be seen in sex chromosomes. Also, the existence of different arrangements of vertebrate sex chromosomes offers tantalizing research opportunities.
The current constitution and future degeneration of sex chromosomes have been discussed widely in scientific literature but the evolutionary history of sex chromosomes has not received commensurate attention. As a postdoctoral fellow, I am collecting data to address Ohno's long-standing hypothesis on the origin of heteromorphic sex chromosomes. Sex chromosomes, as exemplified in birds and mammals, are believed to have arisen from a pair of ancestral reptilian autosomes. Doctor Edwards and I will screen bacterial artifical chromosome (BAC) libraries and genome databases to characterize sequences that are sex-linked, sex-specific, and sex-determining in birds and mammals and compare their structure to potential homologs in reptiles. We will characterize transitions from ancestral autosomes in reptiles to derived heteromorphic sex chromosomes in birds and mammals. Our results will have immediate implications for research on sex-determining mechanisms and broader relevance for research on the evolution of sex and causes of sympatric speciation.


19) Janes, D.E., C.K. Swing, and L.M. Cataldo. From Cambridge to the Amazon in a few simple steps. The American Biology Teacher (In Press).

18) Janes, D.E., N. Valenzuela, T. Ezaz, C. Amemiya, and S.V. Edwards. 2011. Sex chromosome evolution in Amniotes: Applications for Bacterial Artificial Chromosome libraries. Journal of Biomedicine and Biotechnology 2011: 132975.

17) Janes, D.E., C. Chapus, Y. Gondo, D.F. Clayton, S. Sinha, C.A. Blatti, C.L. Organ, M.K. Fujita, C.N. Balakrishnan, and S.V. Edwards. 2010. Reptiles and mammals have differentially retained long non-coding sequences from the amniote ancestor. Genome Biology and Evolution doi: 10.1093/gbe/evq087 .

16) Janes, D.E. 2010. Extinct and extant reptiles: a model system for the study of sex chromosome evolution. Pp. 3-18. In: Pontarotti, P. (ed.). Evolutionary Biology-Concepts, Molecular and Morphological Evolution. Springer, Inc. New York, NY.

15) Janes, D.E., M.K. Fujita, C.L. Organ, A.M. Shedlock, and S.V. Edwards. 2010. Genome evolution in Reptilia, the sister group of mammals. Annual Review of Genomics and Human Genetics 11:239-264.

14) Kunstner, A., J.B.W. Wolf, N. Backstrom, O. Whitney, C. Balakrishnan, L. Day, S.V. Edwards, D.E. Janes, B.A. Schlinger, R.K. Wilson, E. Jarvis, W.C. Warren, and H. Ellegren. 2010. Comparative genomics based on massive parallel transcriptome sequencing reveals patterns of substitution and selection across 10 bird species. Molecular Ecology 19(suppl. 1):266-276.

13) Janes, D.E., C.L. Organ, and S.V. Edwards. 2010. Variability in sex-determining mechanisms influences genomic complexity in Reptiles. Cytogenetic and Genome Research 127:242-248.

12) Organ, C.L., D.E. Janes, A. Meade, and M. Pagel. 2009. Genotypic sex determination enabled adaptive radiations of extinct marine reptiles. Nature 461(7262):389-392.

11) Janes, D.E., T. Ezaz, J.A.M. Graves and S.V. Edwards. 2009. Recombination and nucleotide diversity in the pseudoautosomal region of minimally differentiated sex chromosomes in the Emu, Dromaius novaehollandiae. Journal of Heredity 100(2):125-136.

10) Organ, C. and D.E. Janes. 2008. Sex chromosome evolution in Sauropsids. Integrative and Comparative Biology 48(4):512-519.

9) Janes, D.E., T. Ezaz, J.A.M. Graves, and S.V. Edwards. 2008. Characterization, chromosomal location, and genomic neighborhood of a ratite ortholog of a gene with gonadal expression in mammals. Integrative and Comparative Biology 48(4):505-511.

8) Shedlock, A.M., D.E. Janes and S.V. Edwards. 2008. Amniote phylogenomics: Testing evolutionary hypotheses with large-scale DNA sequences from reptiles. Pp. 91-117. In: Murphy, W.J. (ed.). Methods in Molecular Biology: Phylogenomics. Humana Press, Inc. Totowa, NJ.

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

6) Janes, D.E., D. Bermudez, L.J. Guillette, and M.L. Wayne. 2007. Estrogen increases production of males in a temperature-dependent sex-determining reptile. Journal of Herpetology 41(1):9-15.

5) Janes, D.E. and M.L. Wayne. 2006. Quantitative genetic variation in sex-determining response to incubation temperature in the leopard gecko, Eublepharis macularius. Herpetologica 62(1):56-62.

4) Janes, D. 2004. A review of nuisance alligator management in the southeastern United States. Pp. 182-185. In: Shaw, W., L.K. Harris and L. Van Druff (eds.).  Proceedings of the 4th International Symposium on Urban Wildlife Conservation.

3) Janes, D.E. and M.L. Wayne. 2004. Quantitative genetic variation in sex-determining response to incubation temperature in Leopard Geckos. Integrative and Comparative Biology 44(6): 577-577.

2) Janes, D. and W.H.N Gutzke. 2002. Factors affecting retention time of turtle scutes in stomachs of American alligators, Alligator mississippiensis. American Midland Naturalist 148 (1):115-119.

1) Janes, D. 1998. Text review of The Exploratorium Guide to Scale and Structure. Teaching English as a Second Language 3(3): 1-2.




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