Plasmids, generally speaking, are the good-for-nothing freeloaders of the molecular world. DNA fragments, they hang out in a host's cell, replicating steadily, and occasionally hopping over to another host when the opportunity arises.
Usually they're neutral passengers, neither harming, nor providing any service to the host. They exist, it seems, for the sake of existing.
Tony Griffiths, a genetics professor in UBC's Botany Dept., has spent years studying plasmids, particularly those found in the wild fungus Neurospora. Despite their usually benign existence, Griffiths views plasmids as an important gateway to a greater understanding of diverse molecular processes and the properties of DNA, the hereditary material of life.
Griffiths' plasmid research, the way he tells it, has all the elements of a mystery novel -- vagrants, unsuspecting hosts, killers, battles and twists and turns. The more you get into it, the more intriguing it becomes.
The desire to know "who dunnit" is what Griffiths would like to see students gaining from their science education.
Griffiths' desire to help students is part of the reason he has literally written the book on genetics. In fact, his widely used genetics textbook, Introduction to Genetic Analysis, is now in its sixth edition. It seems appropriate that Griffiths, who sees science as a fundamental tool for understanding the world, should be particularly drawn to genetics.
The characteristics of all living things are determined by their genetic composition. An organism's genes or hereditary determiners are found in chromosomes, linear threads in the cell nucleus. Chromosomes contain the DNA (deoxyribonucleic acid), which transmits genetic information.
Neurospora plasmids are found in mitochondria, cell components which provide the cell's energy, and have been found at locations around the world. The presence of the same plasmid in geographically isolated locations has led to speculation about their origins.
"One of the ideas we have about plasmids is that they are very old," says Griffiths. "It's possible plasmids have been around since before the divergence of species in evolution and have since been inherited through different channels of evolution."
Further mystery surrounds the fact that some fungus populations are plasmid free, even when other populations of the same strain have been found to host plasmids. This suggests the possibility that strains can get rid of plasmids by blocking their replication in some way.
Then there's Kalilo, named after a Hawaiian word meaning "hovering between life and death." Contrary to the usual plasmid policy of non-interference, Kalilo is a killer.
Found initially by Griffiths in a Hawaiian fungus, Kalilo is one of a few plasmids which do seem to have an impact on their host. Kalilo replicates within the host mitochondria for a certain period with no apparent effect before suddenly integrating into the host's DNA molecules, disrupting their function and leading to sudden cell death.
"The fungus can be growing at a rate of 10 centimetres per day and then one day it just stops. It won't take up nutrients and can't be revived."
Griffiths describes the presence of plasmids in their fungal hosts as an ongoing war in which hosts occasionally succeed in mutating or finding other ways to kick out plasmids, while plasmids seize the opportunity to move from host to host and sometimes strike a fatal blow.
Since Griffiths' initial discovery of the Kalilo plasmid in Hawaiian fungus, it has been found in many different parts of the world, in different Neurospora species and in at least one other genus of fungus, Gelasinospora.
Although any potential use of the Kalilo plasmid lies a long way down the research road, Griffiths says killer plasmids could eventually be used to control pathogenic fungus and agricultural pests such as rusts or blights.
Ironically, the presence of another plasmid appears to lengthen the life span of a particular fungus strain, which dies in considerably less time if the plasmid is not present.
Despite the mystery surrounding plasmids and their strange behaviour, Griffiths believes lessons learned from the study of Neurospora plasmids may well shed light on the importance of other so-called selfish DNA such as transposons -- also called jumping genes because they can hop from one chromosome to another -- which are found in plants and animals, including humans.
Science, says Griffiths, is a vital key that can open doors to thousands of mysteries. It is this appreciation of science as a tool, and a language, that has motivated Griffiths to direct the mental energy he doesn't expend on plasmids into finding ways to enhance teaching and learning. Griffiths wants students to leave university with a new way of thinking, of seeing things, and of trying to understand the world around them.
"My involvement in trying to improve teaching and learning stems from the fact that I love science thinking," he says.
"Science is a way of knowing about not only your research, but about everything -- your environment, your life. It's something that pervades our lives. And I don't think students always get as much of a sense of this, and an appreciation for science, as they should."
At UBC, Griffiths has focused on improving genetics education. He found students with backgrounds in fields such as biology were having more trouble picking up genetics than students from more quantitative fields such as physics and mathematics.
"Students sometimes have a great deal of difficulty with genetics, usually because they have not encountered that kind of thinking before. Genetics centres largely on active data processing, so we're generating ways for them to get actively involved with data in tutorials, by working in groups and by working on their own."
Recently, Griffiths has been developing training programs and a handbook to help graduate students who work as teaching assistants lead discussions and promote interaction during tutorial sessions. Supported by the university's teaching and learning enhancement fund, these initiatives come as part of an effort to get students more actively involved in the learning process.
"We're trying to steer away from the idea, which dates back to a time when there were no books, of students sitting passively in lectures and just taking notes," he says.
Griffiths' activities in this area are in keeping with an international trend in science education and university education in general -- student-centred learning, a learning process based on active and interactive student learning experiences.
Griffiths is also trying to give much younger students a head start in science education through his involvement with the Association for the Promotion and Advancement of Science Education (APASE), a B.C.-based non-profit organization dedicated to "inspiring curiosity, innovation and lifelong learning through science education."
The organization offers a range of services, such as workshops, publications, and Web-based resources to elementary school teachers and students. It is also working with B.C.'s English-as-a-Second-Language (ESL) community through a unique program to promote "environmental citizenship" among new Canadians. Integrated into the broader ESL curriculum regarding the principles of citizenship, the program helps students develop a sense of place and belonging in their neighbourhoods while drawing attention to environmental concerns such as waste reduction, recycling and energy and water conservation.
Griffiths, who earlier this year was awarded the Genetics Society of Canada's 1997 Award of Excellence for his contributions to genetics research and education, regards his efforts as a small part of a much larger movement to bring about needed changes in science education.
"Science moves so fast now that sometimes it seems all we want to do is to tell students how wonderful our own areas are and about all the latest developments. But somewhere along the line the baby is getting thrown out with the bath water and the deeper understanding skills aren't always getting across," he says.
And Griffiths feels the emphasis on information rather than analysis that sometimes occurs in education is actually reflective of a larger problem.
"It really is a societal thing," he says. "We live in a society so full of distractions that the quiet consideration of things is just not on for young people anymore. They're distracted by video games and television. When are they going sit down and look at plants and animals?"