Featured Research

from universities, journals, and other organizations

How Mutations Are Transmitted From One Generation To The Next

Date:
December 15, 2008
Source:
Montreal Neurological Institute and Hospital
Summary:
A fundamental process in the transmission of genes from mother to child has been identified. The new study identifies a mechanism that plays a key role in how mutations are transmitted from one generation to the next, providing unprecedented insight into metabolic diseases.

A fundamental process in the transmission of genes from mother to child has been identified by researchers at the Montreal Neurological Institute, McGill University. The new study published in the December issue of the journal Nature Genetics identifies a mechanism that plays a key role in how mutations are transmitted from one generation to the next, providing unprecedented insight into metabolic diseases.

Related Articles


DNA that is only passed on from mothers to their children is stored in mitochondria, a compartment of cells which functions to supply energy to the body. Mutations in mitochondrial DNA (mtDNA) are important causes of over 40 known types of diseases and disorders which primarily affect brain and muscle function, some of which are severely debilitating, with symptoms including stroke, epilepsy, deafness and blindness. One very common mutation in Quebec causes maternally inherited blindness which has now been traced back to a Fille du Roi sent by the king of France in the 1600s to rectify the imbalance of gender in the newly colonized country.

MNI researchers have located a genetic bottleneck that determines the proportion of mutated mtDNA that mothers transmit to their offspring. This is important because there are many copies of mitochondria in cells and their distribution in tissues has a role in the severity and symptoms of the disease. Therefore knowing how mtDNA is transmitted is essential for the understanding and treatment of a range of maternally inherited diseases, and provides an opportunity for genetic counselling and treatment.

"The proportion of mutated DNA copies shifts rapidly and unpredictably from mother to child making it very hard to predict what proportion of mutated DNA will be passed on." says Dr. Eric Shoubridge, neuroscientist at the MNI and lead investigator in the study. "We now understand that this is partly due to the genetic bottleneck, in which just a small number of the original mtDNA copies from the mother are actually transmitted to the child. This bottleneck occurs during the development of eggs in affected females.

Only a small set of the female's mtDNA is selected to replicate resulting in the individual producing eggs with a wide range of proportions of mutated mtDNA. These eggs give rise to offspring with proportions of mutated mtDNA that differ from each other and are different from the proportion of mutated mtDNA in the mother. This explains why the occurrence and severity of a disease from mutated mtDNA can vary in offspring of an affected mother. The identification and location of the genetic bottleneck in our study strengthens our knowledge of the rules and processes of transmission and improves our capacity for genetic counselling."

An important application of this study is in the prevention of the disease at the prenatal stage because therapies for sick patients are usually ineffective, and the diseases are often fatal. The study locates the bottleneck as occurring during the process of egg maturation in early postnatal life of a female, supporting the knowledge that mature oocytes or egg cells contain the full set of copies of mtDNA. This evidence makes possible pre-implantation genetic diagnosis, in which an oocyte is screened for harmful mutations prior to fertilization, for in-vitro fertilization for example. This prevents the transmission of harmful mutations and can avoid the termination of a pregnancy in cases where an embryo is carrying a fatal neurological disorder.

This research was supported by the Canadian Institutes of Health Research and the US National Institutes of Health. Eric Shoubridge is an International Scholar of the Howard Hughes Institute.


Story Source:

The above story is based on materials provided by Montreal Neurological Institute and Hospital. Note: Materials may be edited for content and length.


Cite This Page:

Montreal Neurological Institute and Hospital. "How Mutations Are Transmitted From One Generation To The Next." ScienceDaily. ScienceDaily, 15 December 2008. <www.sciencedaily.com/releases/2008/12/081211161739.htm>.
Montreal Neurological Institute and Hospital. (2008, December 15). How Mutations Are Transmitted From One Generation To The Next. ScienceDaily. Retrieved March 27, 2015 from www.sciencedaily.com/releases/2008/12/081211161739.htm
Montreal Neurological Institute and Hospital. "How Mutations Are Transmitted From One Generation To The Next." ScienceDaily. www.sciencedaily.com/releases/2008/12/081211161739.htm (accessed March 27, 2015).

Share This


More From ScienceDaily



More Plants & Animals News

Friday, March 27, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Jockey Motion Tracking Reveals Racing Prowess

Jockey Motion Tracking Reveals Racing Prowess

Reuters - Innovations Video Online (Mar. 26, 2015) — Using motion tracking technology, researchers from the Royal Veterinary College (RVC) are trying to establish an optimum horse riding style to train junior jockeys, as well as enhance safety, health and well-being of both racehorses and jockeys. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Bear Cubs Tumble for the Media

Bear Cubs Tumble for the Media

Reuters - Light News Video Online (Mar. 26, 2015) — Two Andean bear cubs are unveiled at the U.S. National Zoo in Washington, D.C. Alicia Powell reports. Video provided by Reuters
Powered by NewsLook.com
Botswana Talks to End Illegal Wildlife Trade

Botswana Talks to End Illegal Wildlife Trade

AFP (Mar. 25, 2015) — Experts are gathering in Botswana to try to end the illegal wildlife trade that is decimating populations of elephants, rhinos and other threatened species. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Elephants Help Keep 18-Wheeler From Toppling Over

Elephants Help Keep 18-Wheeler From Toppling Over

Newsy (Mar. 25, 2015) — The Natchitoches Parish Sheriff&apos;s Office discovered two elephants keeping a tractor-trailer that had gotten stuck in some mud upright on a highway. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins