Ip Chi Yuen Stephen

Dr Ip Chi Yuen Stephen 葉志遠

Dr. Ip began his research career as a molecular biologist in the University of Hong Kong under the supervision of Dr. Frederick C. Leung, and developed his research interests in the mechanism of recombinational DNA repair during his D.Phil. studies in Prof. David Sherratt's Lab in the University of Oxford.  In his PhD work, Dr. Ip discovered that the XerCD-dif site-specific recombination machinery, which converts bacterial chromosomal dimer to monomers, can also promote the removal of final catenation links remaining upon completion of DNA replication (EMBO J 2003, Vol.22, p6399-6407).

Dr. Ip then moved on and worked as a post-doctoral research fellow with Dr. Stephen West in Cancer Research UK, where Dr. Ip and his colleagues identified the long-sought human Holliday Junction (HJ) Resolvase (Nature 2008, Vol.456, p357-61), which have proved elusive for almost seventeen years after the discovery of ruvC gene, the bacterial HJ resolvase in Escherichia coli.  The HJ resolvase is of particular importance, as during meiosis and homologous DNA repair, a four-stranded DNA intermediate known as a Holliday junction is formed.  This structure covalently links two DNA molecules and the presence of a HJ resolvase is there a must in order to allow the chromosomes to segregate and replicate properly.

Current work

Dr. Ip joined the Government Laboratory in 2009.  His present duties include attending crime scene and analyzing various pieces of evidence, in particular biological samples that are collected, and then tries to project what had exactly happened.  Besides the routine casework duty, Dr. Ip has to work closely with police officers and other forensic professionals, including forensic pathologists, fingerprint and ballistics experts, in crime scene reconstruction.  He is actively involved in the R&D work and has actively published in international peer reviewed journals.  In May 2016, Dr. Ip has been admitted as a Professional Member of The Chartered Society of Forensic Sciences (MCSFS), U.K., and is a qualified expert in bloodstain pattern analysis.

Selected Publication (corresponding author):

  • Lin, S.W.*†, Lam, T.T.*, and Ip, S.C.* (2019)  Population data of 23 autosomal STR loci in Hong Kong Chinese. Forensic Sci. International: Genetics 39:e24-e25. (* co-authors)
  • Ip, S.C.*†, Lin, S.W.*, and Lam, T.T. (2019) Haplotype data of 27 Y-STR loci in Hong Kong Chinese. Forensic Sci. International: Genetics 38:e14-e15. (* co-authors)
  • Lin, S.W., Li, C., and Ip, S.C.† (2018) A performance study on three qPCR quantification kits and their compatibilities with the 6-dye DNA profiling systems. Forensic Sci. International: Genetics 33:72-83.
  • Lin, S.W., Li, C., and Ip, S.C.† (2017) A selection guide for the new generation 6-dye DNA profiling systems. Forensic Sci. International: Genetics 30:34-42.
  • Lin, S.W.*, Ip, S.C.*†, Lam, T.T., Tan, T.F., Yeung, W.L., and Tam, W.M.†  (2017) Compatibility of DNA-IQ™, QIAamp® DNA Investigator and QIAsymphony® DNA Investigator® with various fingerprint treatments. Int. J. Legal Med. 131(2):293-301. (* co-authors)
  • Ip, S.C.†, and Lai, K.M.† (2016) An evaluation of the precision of QIAGEN Quantiplex HYres kit as a screening tool on low level touch DNA evidence. Eur. J. Forensic Sci. 3(2), 61–67.
  • Ip, S.C.†, Lin, S.W., and Lai, K.M.† (2015). An evaluation of the performance of five extraction methods: Chelex® 100, QIAamp® DNA Blood Mini Kit, QIAamp® DNA Investigator Kit, QIAsymphony® DNA Investigator® Kit and DNA IQ™. Science & Justice 55, 200–208.
  • Ip, S.C.†, Lin, S.W., Li, C., and Lai, K.M. (2014). Forensic DNA typing strategy of degraded DNA on discarded cigarette ends using the AmpFℓSTR® Identifiler®, Identifiler® Plus and MiniFiler™ PCR Amplification Kits. Science & Justice 54, 311–315.
  • Ip, S.C.*, Rass, U.*, Blanco, M.G.*, Flynn, H.R., Skehel, J.M., and West, S.C. (2008).  Identification of Holliday junction resolvases from humans and yeast.  Nature 456, 357–361. (* co-authors)
  • Ip, S.C., Lau, J.S., Au, W.L., and Leung, F.C. (2004). Characterization of the 5’-flanking transcriptional regulatory region of chicken growth hormone gene. Exp. Biol. Med. (Maywood) 229, 640–649.
  • Ip, S.C., Bregu, M., Barre, F.X., and Sherratt, D.J. (2003). Decatenation of DNA circles by FtsK-dependent Xer site-specific recombination. EMBO J. 22, 6399–6407.
  • Ip, S.C., Zhang, X., and Leung, F.C. (2001). Genomic growth hormone gene polymorphisms in native Chinese chickens. Exp. Biol. Med. (Maywood) 226, 458–462.

Other awards:

  • Hardiman-Redon Prize (2009), Cancer Research UK
  • Domus Research Studentships, Linacre College (2002)
  • Hong Kong Oxford Scholarship Fund (2001)