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James Till

Dr. James Edgar Till O.C., O.Ont., F.R.S.C. (born 1931) is a Canadian biophysicist, best known for demonstrating – with Ernest McCulloch – the existence of stem cells.


Early work

Till was born in Saskatchewan, Canada at Lloydminster, which is located on the border between Saskatchewan and Alberta. The family farm was located north of Lloydminster, in Alberta; the eastern margin of the farm was the Alberta-Saskatchewan boundary.

He studied science at the University of Saskatchewan, finishing his bachelor's degree in 1952 and his master's in physics in 1954. Some of this early work was with Harold E. Johns, a pioneer in cobalt-60 radiotherapy.

Till completed his Ph.D. in biophysics at Yale University in 1957.

Stem cells

Harold Johns recruited Till to the Ontario Cancer Institute at Princess Margaret Hospital shortly after he completed his work at Yale. Subsequently, Till chose to work with Ernest McCulloch. Thus, the older physician's insight was combined with the younger physicist's rigorous and thorough nature.

In the early 1960s, McCulloch and Till started a series of experiments that involved injecting bone marrow cells into irradiated mice. They observed that small raised lumps grew on the spleens of the mice, in proportion to the number of bone marrow cells injected. Till and McCulloch dubbed the lumps 'spleen colonies', and speculated that each lump arose from a single marrow cell: perhaps a stem cell.

In later work, Till and McCulloch were joined by graduate student Andy Becker. They cemented their stem cell theory and in 1963 published their results in Nature. In the same year, in collaboration with Lou Siminovitch, a trailblazer for molecular biology in Canada, they obtained evidence that these same marrow cells were capable of self-renewal, a crucial aspect of the functional definition of stem cells that they had formulated.

In 1969, Till became a Fellow of the Royal Society of Canada.

Later career

In the 1980s Till's focus shifted, moving gradually into evaluation of cancer therapies, quality of life issues, and Internet research, including Internet research ethics and the ethics of List mining.

Till holds the distinguished title of University Professor Emeritus at the University of Toronto.

Recently, Till has been a vocal proponent of Open Access to scientific publications.


  • 1993, awarded Robert L. Noble Prize by the National Cancer Institute of Canada
  • 1994, made an Officer of the Order of Canada
  • 2000, made a Fellow of the Royal Society of London
  • 2004, inducted into the Canadian Medical Hall of Fame
  • 2005, he and Ernest A. McCulloch were awarded the Albert Lasker Award for Basic Medical Research
  • 2006, made a member of Order of Ontario

Selected publications

  • Till, J.E., McCulloch, E.A. (1961) A direct measurement of the radiation sensitivity of normal mouse bone marrow cells. Radiation Research 14:213-22.
  • Becker, A.J., McCulloch, E.A., Till, J.E. (1963) Cytological demonstration of the clonal nature of spleen colonies derived from transplanted mouse marrow cells. Nature 197:452-4.
  • Siminovitch, L., McCulloch, E.A., Till, J.E. (1963) The distribution of colony-forming cells among spleen colonies. Journal of Cellular and Comparative Physiology 62:327-36.
  • Sutherland, H.J., Llewellyn-Thomas, H., Boyd, N.F., Till, J.E. (1982) Attitudes toward quality of survival. The concept of "maximal endurable time". Medical Decision Making 2(3):299-309.
  • Mayer, M., Till, J.E. (1996) The Internet: a modern Pandora's box? Quality of Life Research 5(6):568-71.
  • Till, J.E. (2001) Predecessors of preprint servers. Learned Publishing 14(1):7-13.
  • Till, J.E. (2003) Success factors for open access. Journal of Medical Internet Research 5(1):e1.
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "James_Till". A list of authors is available in Wikipedia.
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