Human Migration and Evolution
Dr Cheng, Lydia Yuk Luen (鄭玉鸞)
Lecturer, Department of Biochemistry
BSc (Hon), MSc (Warwick); PhD (HK)
- Email: email@example.com
- Tel: (852) 2819 9277; 2819 2817 (lab)
- Office: L3-68, Laboratory Block, 21 Sassoon Road, Hong Kong
Postgraduate Research Projects Available:
- Evolutionary analysis based on study of haplotype variations in human mitochondrial DNA
My research interest is in human migration and evolution. Analyses of mitochondrial DNA (mtDNA) and the Y chromosome are used to reconstruct human lineages. These are chosen for their unique mode of inheritance: mtDNA is maternal and the Y is paternal. Unlike the other DNAs, they both lack recombination and are liable to high rates of neutral mutation, e.g. mutations in mtDNA are known to occur at least ten times faster than nuclear DNA, making them good candidates for polymorphism studies. Through collaborations with colleagues in China, we are collecting samples from the Northern and Southern Hans as well as minority groups. In such studies, it is important to identify the ancestry of the human subjects. The Chinese are well known to keep a book of genealogy in their family but these may not always be reliable. A linguist specializing in Chinese dialects have been recruited to assist in verifying the ancestry of our samples. Statistics and phylogenetics are used for data processing.. In addition to looking at migratory patterns, the data can also help us to identify genetic diseases that are specific to the Chinese. It is hoped that such studies will help to enrich the understanding of our cultural heritage and also in the investigation of genetic diseases in the Chinese.
Other Research Interests:
The effects of male accessory sex gland secretions on fertility
The male ASG secretions are known to play a role in the maintenance of fertility but their exact functions have not been established. Detailed information on the nature of their secretions have been scanty. Together with Dr. P. Chow of the Dept. of Anatomy, CUHK, we set out to systematically study the components of these glands with the aim to isolate those that play a vital role in male fertility. Different enzymes, including the proteases, lipases, neuraminidases, as well the lipoproteins and electrolytes have now been documented. Three proteins from the ventral prostate have been shown to bind specifically to the sperm membrane after ejaculation and it is believed that they are carried into the ovum where they affect embryonic development. We are in the process of characterizing these proteins. Results from this should shed light on the fertilization process and help in the development of male contraceptives in the future.
Publications, Achievements, and Grants:
- Wong, W.M., Lam, V.M.S., Cheng, L.Y.L., Tam, T.W.O. (1988) Genomic sequence of a Sprague-Dawley rat beta-globin gene. Nucleic Acids Res. 16, 2342.
- Hui, C.C., Cheng, L.Y.L., Lam, V.M.S., Tam, TWO. (1988) Molecular cloning of a gene coding for abundant transcript in red blood cells of anaemic rat. Birth Defects Original Articles Series 23(5A), 139. March of Dimes Birth Defects Foundation.
- Wong, W.M., Au, D.M.Y., Lam, V.M.S., Tam, J.W.O., Cheng, L.Y.L. (1990) A simplified and improved method for the efficient double-strand sequencing of miniprep plasmid DNA. Nucleic Acids Res. 18, 5573.
- Lam, V.M.S., Gu, Y.L., Au, D.M.Y., Wong, W.M., Cheng, L.Y.L. (1993) Two new rat alpha-globin genes identified by the conserved region PCR. Hemoglobin 17, 363-371.
- Au, D.M.Y., Wong, W.M., Tam, J.W.O., Cheng, L.Y.L., Lam, V.M.S. (1995) Genomic organisation and characterisation of a three-gene adult beta-globin haplotype. Gene 165, 261-266.
- Chow, P.H., Yuen, A.C.Y., Cheng, L.Y.L. (1995) Quantitative electrophoretic study of the modification of sperm plasma membrane by the ampullary gland in the golden hamster. Arch. Androl. 34, 53-61.
- Cheng, L.Y.L., Yuen, A.C.Y., Chow, P.H. (1995) Electrophoretic modification of sperm plasma membrane by ventral prostate secretions in the golden hamster. Arch. Androl. 35, 13-20.