As a result of their work on BACTERIA, Canadian researchers Avery and Colin M. MacLeod and American Maclyn McCarty were the first to provide firm evidence that DNA was the genetic material in the cell (1944). The structure of DNA is a double helix, first described in 1953 by Nobel laureates (1962) J.D. Watson (an American who had been influenced by Avery's work) and British researcher Francis Crick. The double helix is composed of 2 antiparallel chains of sugar-phosphate "backbones" with complementary pairs of nucleic acid bases in the centre.
American biochemist Erwin Chargaff's observation of base pairing was important to Watson and Crick's discovery, as were the X-ray diffraction studies of British biophysicist Rosalind Franklin. Just before the elucidation of the structure of DNA by Watson and Crick, G. Wyatt (now at Queen's University) described 5-methylcytosine, the first modified base found in DNA molecules, and confirmed base pairing and the base composition of a number of DNAs.
DNA was postulated as the template for RNA synthesis by French biochemists Jacques Monod and François Jacob (NOBEL PRIZE, 1965). RNA synthesis is called transcription; protein synthesis from the RNA transcript is called translation. Once the protein is translated, depending on the type of cell, it can then undergo a series of changes (eg, addition of carbohydrate or lipid) to make the complex proteins that are part of many cells.
A large part of research in molecular biology has been undertaken on VIRUSES, the simplest of life forms, because they have no complex cellular structure or cell membrane. Some of the earliest basic studies on viral systems were made by Canadian researcher Felix d'Herelle, who independently discovered bacteriophages (bacterial viruses). Viruses are composed either of DNA or RNA with associated proteins, and thus can be used as model systems for examining replication (DNA synthesis), transcription and translation.
Bacteriophages were the first to be examined in detail. DNA synthesis is best understood in these viruses mainly because of studies led by American biochemist A. Kornberg (Nobel Prize, 1959). More recently, eukaryotic viruses (those that attack nucleated cells) have been used. The virus can be considered a microcosm of the cells and tissues of animals, and its molecular biology is controlled by mechanisms analogous to those in cells. Viruses that have RNA as their genetic material are called retroviruses; some retroviruses have been implicated in human CANCER. However, most viruses that attack eukaryotic cells are DNA viruses.
Molecular biology has expanded as a result of the application of recombinant DNA techniques (GENETIC ENGINEERING), following the isolation of restriction enzymes in 1970 by American biochemist Hamilton Smith (Nobel Prize, 1978). Restriction enzymes cut DNA molecules at specific sites (base sequences); joining enzymes can link together the DNA fragments.
In 1977 the first recombinant molecules composed of mammalian DNA inserted into bacterial elements (plasmids) were constructed. Plasmids are particles found in some bacterial cells that contain DNA, but they are not part of the chromosomal apparatus of the bacterium. The next important discovery was of "gene splicing"; ie, the RNA synthesized from the DNA of eukaryotic cells can be much larger than the final messenger RNA product, because those segments of the RNA product that are not necessary to code for the protein message are cut out, and the remaining RNA spliced together.
This work was followed by the development of powerful, fast and relatively easy methods for determining the base sequence of DNA (the order of the base components in DNA). Two laboratories, those of Walter Gilbert in Cambridge, Massachusetts, and Fred Sanger in Cambridge, England, developed different methods. Gilbert, Sanger and Californian Paul Berg (who performed the first cloning experiments) received a Nobel Prize in 1980.
Changes in Classical and Molecular Genetics
Role of Canadians
Canadians have played an important part in the development of molecular biology. Gobind Khorana (Nobel Prize, 1968), the first to chemically synthesize a nucleic acid molecule, started his work at the BC Fisheries Research Laboratories in Vancouver. Khorana's many students include Gordon Tener, who developed a chromatographic column for separating nucleic acids over a range of sizes, an innovation that has had tremendous methodological impact on molecular biology, and
Groups are now undertaking research in molecular biology in all major Canadian universities (within laboratories in faculties of medicine and science), in the BIOTECHNOLOGY companies located in most provinces, and in many federal and provincial laboratories.
Author JOHN H. SPENCER
Links to Other Sites
Rosie Redfield: Critical enquirer
A profile of UBC microbiologist Rosie Redfield, whose "quest to replicate 'arsenic life' led to a remarkable experiment in open science." Proclaimed as one of "Ten people who mattered this year" in 2011 by the science journal "Nature".
Click on the names of Nobel Laureates for biographies, interviews, speeches, and more. From the Nobel Foundation, home of the Nobel Prizes.
Canadian Society of Biochemistry, Molecular and Cellular Biology
A professional society that supports biochemistry research in Canada. Check out the winners of awards for outstanding Canadian research. Also, click on "Student Activities" for information about the "Rising Stars of Research" program.
The latest news and in-depth reports about current issues in science from the "Scientific American" website.
This BIOTECanada website provides a basic overview of Canadian biotechnology research projects and industrial applications.
Canadians for Health Research
The website for Canadians for Health Research provides the latest news and information about programs that promote science and health research initiatives in Canada.
Dr. Michael Smith
A profile of scientist Dr. Michael Smith, winner of the 1993 Nobel Prize in chemistry. From the Canadian Medical Hall Of Fame and the Virtual Museum of Canada.
INDEPTH: Biological Weapons
This CBC Backgrounder website examines Canada’s high-tech virology lab in Winnipeg. Features a biowar dictionary and timeline, news stories about infectious diseases and more.
Worldwide coverage of the latest science news from the highly acclaimed science journal "Nature."
Canadian Science Policy Centre
The latest news and information about Canada's science sector.
All the latest news for the scientific community, including daily news from ScienceNOW and weekly news from Science magazine.
Canadian Bioethics Society
The website for the Canadian Bioethics Society, an organization concerned with ethical issues relating to human life and health, biology, and the environment. Click on "Bioethics Community" to access their blog and other online resources.
The website for Sanofi Pasteur, the vaccines division of sanofi-aventis Group. In the upper menu, click on "Sanofi Pasteur in Canada" for a brief history of Connaught Laboratories and a profile of founder Dr. John G. FitzGerald.
Public Health Agency of Canada
Check this site for the latest news about current health issues. Covers chronic disease prevention, public health emergencies, infectious disease outbreaks, and other topics related to health hazards.
A brief biography of Dr. Louis Siminovitch, eminent Canadian medical scientist. From The Elinore & Lou Siminovitch Prize in Theatre website.
Canadian Light Source Inc.
The website for the Canadian national synchrotron light research facility at the University of Saskatchewan. Features colourful online brochures about synchrotron science and related applications in biomedicine, agriculture, engineering, and other disciplines. Also offers a futuristic photo gallery and teachers’ resources. Some pdf files.
This glossary was developed to help you understand the terms used in the field of biotechnology. From the website for Health Canada.
The website of the Canadian Institute for Advanced Research. Check out their latest scientific research projects in their online publications "Reach" and "Scope."
Student Science & Tech
Science comes alive at this site which features interactive microscopes, fantastic photos, a colourful periodic table, and much more. Check out the amazing stories about Canada's leading scientists. From the National Research Council Canada.
An extensive multimedia information source about basic genetic research and related applications in medicine, energy production, and the environment. Features educational resources for students and their teachers. From the website for the Office of Biological & Environmental Research.
Let's Talk Science
Let's Talk Science offers interactive learning programs and resources for teachers and their students.
Creation of genes in lab raises hopes, concerns
A brief news story that addresses ethical concerns related to the development of the first cell that contains only synthetic genetic material. From the SFGATE.com website.
Shawnadithit grew anxious waiting for her uncle, Longnon, to return to camp at the junction of Badger Brook and the Exploits River, deep in the wilds of Newfoundland...