The stem cell discovery

Joe Sornberger
23 January 2012

In proving the existence of stem cells, Ernest Armstrong McCulloch and James Edgar Till made one of the most important advancements in Canadian medical research since Banting and Best discovered insulin. Yet these Toronto-based scientists remain all but unknown to most Canadians.

Did You Know?
Canadians have made many of the world’s major stem cell discoveries including neural stem cells, skin stem cells and retinal stem cells.

How they did it

Till and McCulloch were experimenting on mice to understand the effects of radiation on blood when they discovered that certain cells produced“colony-forming units” containing the cells needed to make blood while also renewing themselves. In other words, stem cells. They published their results in 1961, and in 1963 followed up with a paper considered the definitive demonstration of how stem cells function.

Did You Know?
McCulloch’s colleagues called him “Bun,” a nickname that he had picked up as a child and – though he tried – could not shake his entire life.

Different as chalk and cheese

Though they worked wonderfully well together, Till and McCulloch came from entirely different backgrounds and approached their work in very different ways. Till, analytical and methodical, grew up working on an Alberta wheat farm. McCulloch, passionate and percolating with ideas, was a child of privilege who went to Upper Canada College in Toronto. McCulloch liked to quote Shakespeare and Trollope. Till loves to talk about curling.

Thousands of lives saved

Till and McCulloch’s research provided the theoretical basis for bone marrow transplantation. In fact, McCulloch went on to lead the

bone marrow transplantation program at Princess Margaret Hospital in the 1970s,which has saved thousands of lives.

Did You Know?
The duo became known as Till and McCulloch because Till was the lead author on the 1961 breakthrough paper. They took turns going first.

Learn More!

Till & McCulloch inducted into Science & Engineering Hall of Fame

Learn more about Stem Cells on our Stem Cells Theme Page!

Article first published October 21, 2011.

Joe Sornberger

Joe is the author of Dreams & Due Diligence: Till and McCulloch’s Stem Cell Discovery and Legacy, published by University of Toronto Press.

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