University of California, Berkeley
Dept. of Integrative Biology
3060 VLSB #3140
Berkeley, CA 94720-3140
Lab phone: 510/643-6227
Fax: 510/643-5022
Email: yajen@uclink.berkeley.edu
To understand the evolutionary processes, evolutionary developmental biology (evo-devo) has arisen recently as a modern field that combines the evolutionary with developmental biology. Comparative studies of early development have shown that changes in the spatio-temporal use of regulatory genes, as well as changes in the specificity of regulatory proteins, are correlated with important differences in morphology between phylogenetically distant species. The regulatory element evolution, including cis- and trans-regulation, was believed to be the primary force for organismal differentiation. A high turnover rate of gene regulatory elements may uncouple regulatory--element-mediated gene expression and protein evolution. Divergences of the gene expression are suggested to the forces result in hybrid incompabilities of the genes within species and new species formation. However, the evolving processes of regulatory regions and the driving forces that cause divergences of genes among species are still unclear. To address these questions, Odysseus (OdsH), was recognized as a hybrid male sterility gene between Drosophila mauritiana and D. simulans provides an excellent occasion. Rapid evolution of the coding region and functional divergences are spectacular characteristics of OdsH. Nevertheless, the detailed mechanisms that result in species differentiation are still not understood. For solving this question, I want to investigate the regulatory regions of OdsH in D. melanogaster clade by sequence comparison and observing the expression divergences during spermatogenesis. I am also interested in the differentiation of regulatory elements for evolving a new gene from duplication. Functional and sequence analyses of the cis-regulatory elements between OdsH and unc-4, the ancient gene of OdsH, in D. melanogaster are necessary.
The other part of my interest is focused on OdsH function in D. mauritiana-D. simulans hybrids. In the genic view of speciation, speciation genes are loci directly responsible for differential adaptation, which contribute to reproductive isolation. By this definition, several speciation genes have been identified and characterized at the molecular level. However, the genetic interactions between con- and heterospecific alleles in the hybrids and the functional divergence that lead to the reproductive isolation among different populations have not been well understood. As we know that OdsH can cause hybrid male sterility when introgressed from D. mauritiana into D. simulans. An exciting fact was observed in the hybrid sterile males: the testicular expression of OdsH is unusually accumulated in very young spermatocytes. Hybrid incompatibility may be the force to form this phenomenon. In order to test whether hybrid male sterility can be rescued by wild-type D. simulans transgene or not, transgenic assays are used. Compatible D. mauritiana and D. simulans copies of OdsH will be introduced into D. simulans individually and the influences of the male sterility in the specific genetic background will be checked.
Education:
Ph.D. candidate
National Tsing Hua University, Hsinchu, Taiwan
Institute of Molecular and Cellular Biology
Advisor: Dr. Chau-Ti Ting
August 2002-Present
National Tsing Hua Universtiy, Hsinchu, Taiwan
M.S. program in Department of Life Science
Advisor: Dr. Chau-Ti Ting
July 2001 - July 2002 (Switch to PhD program)
National Chung Hsing Unversity, Taichung, Taiwan
B.S degree in Entomology
Sep. 1997 – June 2001
Research Experience:
University of California, Berkeley
Visiting student in Dept. of Integrative Biology
Host: Nipam H. Patel
May 2006- Persent
National Tsing-Hua University, Taiwan
Participate in the National Science Council project “Legal Issues of Invasive Species”.
Advisor: H.-C. Niu, Asst. Professor, Institute of Law for Science and Technology
Jan. 2004 – Dec. 2004
National Chung Hsing Unversity, Taiwan
Volunteer to participate in the topic “Cloning the open reading frame idgC of the Blue pigment gene, RA3B, in Erwinia chrysanthemi” investigation.
Advisor: H.-C. Huang, Professor, Institute of Agricultural Biotechnology (Now is Graduate Institute of Biotechnology)
July 2000 – June 2001
Asian Vegetable Research and Development Center, Taiwan
Summer student for an independent project ”Study of influence of crucifer biochemicals on the attraction and oviposition of Crocidolomia binotalis”.
Advisor: N. S. Talekar, PhD of Entomology
July 1999 – Aug. 1999
Presentations
2005 Evolution Annual meeting, Fairbanks, AK
“Pleiotropic effects of the hybrid sterility gene, Odysseus (OdsH), in Drosophila” (Talk)
2005 Thirteenth Symposium on Recent Advance in Cellular and Molecular Biology, Pingtung, Taiwan
“Genetic analyses of the hybrid sterility gene, Odysseus (OdsH), in Drosophila. (Poster)
2004 Conference of College of Life Science, National Tsing Hua University, Hsinchu, Taiwan
“Functional analysis of reproductive isolation caused by the Odysseus locus in Drosophila melanogaster clade” (Poster)
Teaching Experience
Spring 2002-2004 Teaching Assistant – Genetics, prescribed course of Department of Life Science, National Tsing Hua University. To lead discussion groups twice a week and review worksheets for this undergraduate course.
