A forensic biologist has told a trial that a DNA research tool helped police hone in on the suspect who is now charged with the sexual assault and murder of junior college student Guylaine Potvin nearly 24 years ago. Potvin, shown in a police handout photo, was found dead in her apartment in Jonquière, Que., on April 28, 2000. THE CANADIAN PRESS/HO-Surete du Quebec **MANDATORY CREDIT**
SAGUENAY, Que. – A forensic biologist has told a trial that a DNA research tool helped police hone in on the suspect who is now charged with the sexual assault and murder of a junior college student nearly 24 years ago.
Valérie Clermont-Beaudoin testified today at the Saguenay, Que., jury trial of Marc-André Grenon, who is charged with the first-degree murder and aggravated sexual assault of Guylaine Potvin in April 2000.
Clermont-Beaudoin said the unidentified male DNA collected at the crime scene was run through a database called “projet patronyme,” which analyzes the Y chromosomes of DNA samples and suggests surnames that could be associated with them.
She explained that Y chromosomes are passed down from father to son, as are last names in most cases, which allows biologists to identify tentative last-name matches for unknown DNA.
She said the male DNA collected under Potvin’s fingernails was entered into the database in 2022 and was found to have a very high correspondence with the last name “Grenon,” scoring 94 points of a possible 98.
She said the information was given to police officers, who used it to focus their investigation on the suspect and gather a new DNA sample from a discarded drinking cup and straws he had used.
This report by The Canadian Press was first published Jan. 30, 2024.
