Dan Janes
Ph.D.
Department of Organismic an 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)oeb.harvard.edu
Education:
Ph.D.: University of Florida, Gainesville, FL; Zoology, May 2004
M.S.: University of Memphis, Memphis, TN; Vertebrate Biology; December
1999
Ed.M.: Boston University, Quito, Ecuador; Teaching and Curriculum Design;
December 1998
B.A.: Boston University, Boston, MA; Biology; June 1996
Research Interests:
I am an evolutionary ecologist 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 vertebrates. 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.
Publications:
Janes, D.E., T. Ezaz, J.A.M. Graves and S.V. Edwards. Recombination and nucleotide diversity in the pseudoautosomal region of minimally differentiated sex chromosomes in the Emu, Dromaius novaehollandiae. Journal of Heredity (In press).
Organ, C. and D.E. Janes. 2008. Sex chromosome evolution in Sauropsids. Integrative and Comparative Biology Advance Access. pdf
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 Advance Access. pdf
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. pdf
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 Advance Access. pdf
Janes, D., 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. pdf
Janes, D. 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. pdf
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. pdf
New Chromosome Images from American Alligator:
