Quirks & Quarks for May 27, 2000

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Microbicides and AIDS


Supercolonies of Argentine Ants


The spread of E. coli

New England Journal of Medicine: The risks of using antibiotic treatment for E. coli infection.




Snowball Earth





Genetics column: how many genes in a human?











Microbicides and AIDS

The most traditional way to control the spread of AIDS is by the use of a condom. But women don't wear condoms, and in some countries and cultures, condom use poses problems.

Now scientists are looking at putting the control of AIDS prevention into the hands of women with a microbicide - chemicals that kill or immobilize sexually transmitted viruses. Women can apply these chemicals themselves.

Dr. Mark Wainberg came to speak with us at Quirks about the need to develop effective microbicides. He's the President of the International AIDS Society and the director of the McGill University AIDS centre.

Supercolonies of Argentine Ants

Argentine ants are invading southern California. To rule a colony that's about 100 kilometres long, they are using close relatedness and a lack of genetic diversity to beat out other species of ants. Usually, genetic diversity is what makes a species thrive.

Neil Tsutsui is a graduate student in the department of biology at the University of California at San Diego. He came in to explain to us how the ants are marching two by two billion in California.

Microbial column: the spread of E. coli

What is E. coli and how does it spread? Our regular columnist on microbial matters, Dr. Eleanor Fish, came in to tell us all about the bug that has caused so much anguish in Walkerton, Ontario in recent weeks.

Dr. Fish is an associate professor in the department of immunology at the University of Toronto and senior scientist at the Toronto general research institute.

Snowball Earth

The 'snowball earth' hypothesis suggests that sometime around 600 million years ago, before the evolution of complex animals, a combination of circumstances led to a freezing of our planet that lasted millions of years.

There is mounting geological evidence suggesting this occurred. The problem is there was no theory to explain how this could have happened, and no explanation for how life could have survived such a freezing.

That all changed recently when researchers unveiled a model of the so-called snowball earth, and an explanation for how our simple ancestors might have survived the frigid temperatures. Dr. Richard Peltier, a physicist at the University of Toronto, and part of the snowball earth team, came to explain the ins and outs of the frozen globe to us.

Genetics column: How many genes in a human?

Scientists are working to map the human genome. It will be a huge catalogue of chemical sequences that make up the recipe for human beings. But that won't tell us what the genes do, if they do anything at all, nor will it tell us how many genes there are.

There are a lot of guesses though, and recently at a meeting in the United States, some scientists presented their best estimates of just how many genes there are.

Dr. Vanessa Auld, our regular genetics columnist, came to tell us about those guesses. Dr. Auld is in the zoology department at the University of British Columbia.

Question of the week: Great Lakes and quakes

One of our listeners wanted to know if the low water level in the great lakes could be responsible for the recent increase in quakes in the area. We were a little shaky on our geological knowledge, so we consulted Dr. Gail Atkinson, a seismologist in the earth sciences department at Carleton University, and the Director of the Ottawa-Carleton Earthquake Research Centre, for the answer.

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