- Professor Emeritus, UM, 2007 - present.
- Research Associate, UM, 2000-2007.
- Senior Research Fellow, UM, 1999.
- Professor for Chair of Zoology, UM, 1986-1998.
- Associate Professor, Dept. of Genetics and Cellular Biology, UM, 1974-March 1986.
- Lecturer, School of Biological Science, UM, 1968-June 1974.
- Tutor, Dept. of Zoology, UM, 1965-1968.
- Student Demonstrator, Dept. of Zoology, UM, 1964-1965.
- Genetics, systematics, biodiversity and evolutionary biology
- Economic zoology and medical biology
Awards & Honours
- Systematics, genetics and ecology of fruit flies and other insect pests
- Systematics, genetics and evolutionary biology of stingless bees, braconid parasites and other hymenopterans
- Genetics, immunology and molecular biology of parasites, vectors and hosts
- Systematics, genetics and evolutionary biology of mammals, amphibians, reptiles and fish
- Genetic toxicology
- Animal and human cytogenetics
- Malaysian natural heritage
Publications & Presentations
- Professor Emeritus (Genetics & Zoology), University of Malaya, 2007.
- Senior Fellow (with title Academician), Academy of Sciences Malaysia, 2002.
- JMN (Johan Mangku Negara), 2002.
- Foundation Fellow, Academy of Sciences Malaysia, 1995.
- National Science Award, 1995.
- First Malaysia Toray Science Foundation Science and Technology Award, 1994.
- MPKSN Award for Promotion of Public Understanding in Science and Technology 1996 - Prize and Certificate of Appreciation.
- Commonwealth Academic Staff Fellowship, 1974.
- Royal Society & Nuffield Foundation Commonwealth Bursary, 1971.
- B.Sc. Zoology Book Prize, 1964.
- University of Malaya Senior Scholarship, 1962-1965.
- V.I. Queen Victoria Scholarship, 1962-1965.
- V.I. Goldthorpe Scholarship, 1962-1965.
- Pahang State Scholarship, 1957-1960.
Funded Research Projects
- He has published more than 300 articles and 4 books (the citation databases of ISI listed 109 titles in 1998).
- Editors of several books (Malayan Nature Journal, Malaysian Journal of Science - over 20 years), magazines (Nature Malaysiana - 20 years), monographs, proceedings and Animals volume in Encyclopedia of Malaysia.
- All (national and international) already completed.
- Senior Fellow, Academy of Sciences Malaysia.
- Adjunct Professor, UTAR, 2008 - present.
- Member, Academic Advisory Board, KBU International College, 2008-present.
- Member, Board of Directors, College IKIP Pahang Darul Makmur, present (and past several years).
- Member, Selection Committee, Malaysia Toray Science Foundation Science and Technology Awards and Research Grants, present (and past several years).
- Committee Member and Judge, ACCCIM Young Innovators Programme, 2007-2008.
- Editor, Ecological Research, 2006-present.
- Member, ACCCIM STI Committee, 2006-2008.
- Chief Editor, Journal of Science and Technology in the Tropics, 2004-present.
- Member, Panel of Assessors, National Science Award, 2004.
- International Judge, Intel-ISEF (International Science and Engineering Fair), 2003-2004.
- Chairman, Panel of Advisors, Inti Journal, 2002.
- Chairman, Academic Advisory Board, Kolej Bandar Utama. 2000-2008.
- Honorary Member, Academic Advisory Board, Inti College, Malaysia, 2000-present.
- Member, Panel of Assessors, National Yong Scientists Award / National Technologies Award, 1996-2003.
- Member, Technical Committee, National Botanical Gardens, late 1990s.
- Member, Editorial Board, The Raffles Bulletin of Zoology, since 1990s.
- Member, Advisory Board and Scientific Research Committee, Department of Wildlife and National Parks, MOSTE, 1990s.
- Chairman, Technical Committee for Biological Control of Vertebrates, National Council of Biological Control, 1990s.
- Member, BioNet International, 1990s.
- Member, Commonwealth Science Council Advisory Group on Biodiversity and Genetic Resource, late 1990s.
- Member, Assessment Panel for R&D Projects, Malaysian Rubber Board, late 1990s.
- Invited as speaker and session chairman in various conferences.
- External Examiner and Assessor for promotion exercises in various universities
- Named after the following species of living organisms:
- Topomyia (Topomyia) yongi, 1990.
- Trypanosoma yongi, 1992.
- Johora hoiseni, 1992.
- Aesalus yongi, 1993 (now Echinoaesalus yongi).
- Pardalaspinus yongi, 1995.
- Duliticola hoiseni, 1996.
- Simulium yongi, 1997.
- Cladomyrma yongi, 1999.
- Manota yongi, 2006.
- Simulium (Gomphostilbia) hoiseni, 2008.
- Malayozodarion hoiseni, 2008.
- Kalophrynus yongi, 2009.