Telephone: 6316 7094
- B.A. Peking University, P.R.China
- Ph.D. Baylor University, USA
- Assistant Professor, School of Biological Sciences, Nanyang Technological University, Singapore (since Jan 2009)
- Postdoctoral Fellow, Howard Hughes Medical Institute; Department of Molecular Biology, Massachusetts General Hospital, Boston, USA
Why a dog always gives birth to a dog, never a cat? Classic genetics has given a satisfying answer to this big old question. This is because dogs inherited dog DNA (or the dog “genes”). However, classic genetics provides no answer when the same question is asked at a different level. A single “mother cell” (a fertilized egg) can give rise to all kinds of different cells, skin cells, kidney cells, neurons, blood cells…...In this case, all cells inherited the same DNA from the original egg. Why the cells become so different? “Epi”-genetics helps to answer this question.
In Epigenetics, we study modifications such as DNA methylation, histone modifications and higher order of chromatin structure. These modifications are regarded as the genetic information written on top of the original genetic code (DNA sequence) to regulate gene expression. Epigenetic study will help us understand how different genes are selectively expressed in different cell types.
A perfect model to study epigenetics is X chromosome inactivation. In mammals, each female cell transcriptionally inactivates one of the two X chromosomes to balance the dosage of X-linked genes between male (XY) and female (XX). The two X chromosomes in each female cell can be identical in DNA sequences. However, one X is active, the other X is silenced. Therefore, in this case, the regulation of gene expression solely depends on epigenetic modifications. How the allele specific gene silencing is established, maintained and re-activated during the life cycle are intriguing questions in my research.