Rethinking the Genetic Theory of Inheritance

January 18, 2009

Scientists at the Centre for Addiction and Mental Health (CAMH) have detected evidence that DNA may not be the only carrier of heritable information; a secondary molecular mechanism called epigenetics may also account for some inherited traits and diseases. These findings challenge the fundamental principles of genetics and inheritance, and potentially provide a new insight into the primary causes of human diseases.

Your mother's eyes, your father's height, your predisposition to disease-- these are traits inherited from your parents. Traditionally, 'heritability' is estimated by comparing monozygotic (genetically identical) twins to dizygotic (genetically different) twins. A trait or disease is called heritable if monozygotic twins are more similar to each other than dizygotic twins. In molecular terms, heritability has traditionally been attributed to variations in the DNA sequence.

The video will load shortly
Dr. Art Petronis, head of the Krembil Family Epigenetics Laboratory at the Center for Addiction and Mental Health, discusses new evidence that DNA may not be the only carrier of heritable information; a secondary molecular mechanism called epigenetics may also account for some inherited traits and diseases. These findings challenge the fundamental principles of genetics and inheritance, and potentially provide a new insight into the primary causes of human diseases. Video: Center for Addiction and Mental Health

CAMH's Dr. Art Petronis, head of the Krembil Family Epigenetics Laboratory, and his team conducted a comprehensive epigenetic analysis of 100 sets of monozygotic and dizygotic twins in the first study of its kind. Said Dr. Petronis, "We investigated molecules that attach to DNA and regulate various gene activities. These DNA modifications are called epigenetic factors."

The CAMH study showed that epigenetic factors - acting independently from DNA - were more similar in monozygotic twins than dizygotic twins. This finding suggests that there is a secondary molecular mechanism of heredity. The epigenetic heritability may help explain currently unclear issues in human disease, such as the presence of a disease in only one monozygotic twin, the different susceptibility of males (e.g. to autism) and females (e.g. to lupus), significant fluctuations in the course of a disease (e.g. bipolar disorder, inflammatory bowel disease, multiple sclerosis), among numerous others.

"Traditionally, it has been assumed that only the DNA sequence can account for the capability of normal traits and diseases to be inherited," says Dr. Petronis. "Over the last several decades, there has been an enormous effort to identify specific DNA sequence changes predisposing people to psychiatric, neurodegenerative, malignant, metabolic, and autoimmune diseases, but with only moderate success. Our findings represent a new way to look for the molecular cause of disease, and eventually may lead to improved diagnostics and treatment."

An advance online publication of this study will be available on the Nature Genetics website on January 18, 2009.

Source: Centre for Addiction and Mental Health

Explore further: Team reprograms social behavior in carpenter ants using epigenetic drugs

Related Stories

The first autism disease genes

September 1, 2008

The autistic disorder was first described, more than sixty years ago, by Dr. Leo Kanner of the Johns Hopkins Hospital (USA), who created the new label 'early infantile autism'. At the same time an Austrian scientist, Dr. ...

Pre-eclampsia may be autoimmune disease

July 28, 2008

Biochemists at The University of Texas Medical School at Houston say they are the first to provide pre-clinical evidence that pregnancy-induced high blood pressure or pre-eclampsia may be an autoimmune disease. Their research ...

Recommended for you

How the finch changes its tune

August 3, 2015

Like top musicians, songbirds train from a young age to weed out errors and trim variability from their songs, ultimately becoming consistent and reliable performers. But as with human musicians, even the best are not machines. ...

Machine Translates Thoughts into Speech in Real Time

December 21, 2009

(PhysOrg.com) -- By implanting an electrode into the brain of a person with locked-in syndrome, scientists have demonstrated how to wirelessly transmit neural signals to a speech synthesizer. The "thought-to-speech" process ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

gopher65
3 / 5 (1) Jan 18, 2009
This is very interesting research.
Ashibayai
2 / 5 (1) Jan 19, 2009
I thought this pretty well understood already. Though, I do find this specific experiment to be very interesting.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.