Hong Yunhan (deceased)

Associate Professor

Contact Information:
Department of Biological Science
National University of Singapore
14 Science Drive 4
Singapore 117543
Email: dbshyh@nus.edu.sg

Ph.D. University of Goettingen, Germany


Fish Developmental Genetics, Stem cells, sex and fertility, evolution.


Stem Cells
Stem cells have enormous potential in regenerative medicine and biotechnology. We focus on (1) pluripotency maintenance, restriction and cell fate decisions during embryogenesis; (2) embryonic stem (ES) cell self-renewal and differentiation; and (3) Adult stem cells & niche.

Sex and fertility
The key for human reproduction is the development of sexes & gametogenesis producing eggs & sperm for fertility. Molecular and cellular defects in these processes lead to infertility. We focus on (1) germ cell development and cultivation for reproductive medicine/engineering; (2) germ-soma interactions in sex, gametogenesis & fertility; (3) meiosis entry & progression; (4) test-tube sperm production; and (5) artificial reproductive technologies.

Medakafish as model
The fish medaka is the model. This fish features a small size (4 cm), small genome (1/4 human), short generation time (10 weeks), numerous eggs, external embryogenesis, various inbred lines & mutant strains, good genetics, transgenic lines, transparency throughout life, and many experimental tools. Most importantly, medaka is a unique lower vertebrate that has several stem cell lines, including recently established haploid ES cell lines capable of producing fertile nuclear transplants, the fish “Dolly”, providing unique opportunities for analyzing recessive phenotypes in various cell lineages. We are interested in transcriptional regulation in stem cells and translation regulation in germ cells. Our approaches include cell culture, embryo microinjection & gene transfer in culture and embryos.


First ES cell lines besides mouse
First normal vertebrate spermatogoinal cell line from adult medaka testis
First test-tube sperm from medaka spermatogonial cell line
First haploid ES cell lines from medaka
'Holly' the first semi-cloned fish by medaka haploid ES cell nuclear transfer
Top 100 scientists, Chinese Academy of Science & Technology
2005 NUS Outstanding Researcher Award.


    Yi M, Hong N, Hong Y. 2009. Generation of medaka fish haploid embryonic stem cells. Science 326: 430-3.

    Xu H, Li Z, Li M, Wang L, Hong Y. 2009. boule is present in fish and bisexually expressed in adult and embryonic germ cells of Medaka. PLoS ONE 4:e6097.

    Yan Y, Du J, Chen T, Yi M, Li M, Wang S, Li CM, Hong Y. 2009. Establishment of medakafish as a model for stem cell-based gene therapy: Efficient gene delivery and potential chromosomal integration by baculoviral vectors. Exp Cell Res 315: 2322-31.

    Li M, Hong N, Xu H, Yi M, Li C, Gui J, Hong Y. 2009. Medaka vasa is required for migration but not survival of primordial germ cells. Mechanisms of Development126:366-81.

    Lo L, Zhang Z, Hong N, Peng J, Hong Y. 2008. 3640 unique EST clusters from the medaka testis and their potential use for identifying conserved testicular gene expression in fish and mammals. PLoS ONE. 3:e3915.

    Hong Y, Liu T, Zhao H, Xu H, Wang W, Liu R, Chen T, Deng J, Gui J. 2004. Establishment of a normal medakafish spermatogonial cell line capable of sperm production in vitro. Proc Natl Acad Sci USA 101, 8011-6.