Featured Research

from universities, journals, and other organizations

How mitochondrial genes are passed from mother to child

Date:
May 3, 2012
Source:
Oregon Health & Science University
Summary:
This finding helps answer some long-standing questions about how mitochondria-linked gene mutations are inherited. Gene mutations in cell mitochondria can cause several diseases, including forms of cancer, diabetes, infertility and neurodegenerative diseases. With this new information, we now better understand how and when these mutations are passed to children to improve diagnosis and prevention.

Fused cells.
Credit: Image courtesy of Oregon Health & Science University

Research conducted at the Oregon National Primate Research Center at Oregon Health & Science University helps answer some long-standing questions about how certain disease-causing gene mutations are inherited.

The research specifically focused on gene mutations in cell mitochondria that can cause several diseases, including forms of cancer, diabetes, infertility and neurodegenerative diseases. With this new information, we now better understand how and when these mutations are passed to children to improve diagnosis and prevention.

The research will be published online in the journal Cell Reports on May 3.

Shoukhrat Mitalipov, Ph.D.,who previously developed a method for preventing the passing of mitochondrial genetic mutations from mother to infant in 2009, directed the research.

This latest breakthrough, which was conducted in rhesus macaque monkeys because of their similarity to humans, demonstrates the specific stage of early embryonic development when genetic mutations are passed from mother to fetus. This stage, referred to by scientists as "the bottleneck," occurs when an early embryo called blastocyst, transitions into a fetus.

To conduct the research, Mitalipov and colleagues needed to design a way to mark and track specific mitochondrial genes as they transitioned from egg, through fertilization, to embryo and then to fetus. This was accomplished by combining two separate mitochondrial genomes into one egg cell. More specifically, one-half of an egg cell from a species of Indian-continent rhesus macaque monkey was merged with one-half of an egg cell from a Chinese-continent monkey. Because these animal species have distinct mitochondrial gene sequences (like breeding two distinct species of dogs), their genetics could be tracked closely.

The microscopic manipulation of splitting and uniting two halved egg cells takes specialized skills and expertise, which the Mitalipov lab has developed over a period of several years.

By studying the development of these joined and then fertilized eggs, scientists were surprised to see that eggs transitioned from containing a 50/50 split of genetics to a fetus that contained a nearly 100 percent either Indian or Chinese-based genome.

"We discovered that during early development, each individual cell in the eight-cell embryo would contain varying percentages of the Indian and Chinese rhesus genes. Some would be a 50/50 split. But others would be 90/10 and so on," explained Mitalipov. "When these percentages were combined as a whole embryo, the average genetic split between the two species was about equal as initially created. However, later during the transition from a blastocyst to fetus, the genetics would swing one way or another. The resulting offspring would have always a genome that is predominantly Chinese or Indian. Our study tells us precisely when this mitochondrial gene switch occurs and how this can lead to disease."

This finding raises significant questions about validity of currently methods for genetic diagnosis in early embryos, when a woman is known to carry a mitochondrial gene mutation may pass a disease to her children.

"The current pre-implantation genetic diagnosis method is to examine genetic disease risk is by taking one cell from an early eight-cell embryo, and then looking for mutations in that one particular cell. This is done to predict if the remaining embryo is mutation-free," explained Mitalipov.

"The problem with this approach is that you may choose a cell that may not have mutations. But that does not mean the remaining cells in an embryo are mutation-free. Our research suggests that such approach could be flawed because diagnosis takes place prior to the stage when an offspring's mitochondrial genetics is truly established."

With this new information and with additional data gathered through further research, Mitalipov and colleagues believe that new methods for genetic diagnosis for mitochondrial disease should be located. The research also demonstrates that the Mitalipov lab's previously developed method for preventing the passing of mitochondrial mutations from mother to child is highly successful.


Story Source:

The above story is based on materials provided by Oregon Health & Science University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Hyo-Sang Lee, Hong Ma, RitaCervera Juanes, Masahito Tachibana, Michelle Sparman, Joy Woodward, Cathy Ramsey, Jing Xu, Eun-Ju Kang, Paula Amato, Georg Mair, Ralf Steinborn, Shoukhrat Mitalipov. Rapid Mitochondrial DNA Segregation in Primate Preimplantation Embryos Precedes Somatic and Germline Bottleneck. Cell Reports, 2012; DOI: 10.1016/j.celrep.2012.03.011

Cite This Page:

Oregon Health & Science University. "How mitochondrial genes are passed from mother to child." ScienceDaily. ScienceDaily, 3 May 2012. <www.sciencedaily.com/releases/2012/05/120503125812.htm>.
Oregon Health & Science University. (2012, May 3). How mitochondrial genes are passed from mother to child. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2012/05/120503125812.htm
Oregon Health & Science University. "How mitochondrial genes are passed from mother to child." ScienceDaily. www.sciencedaily.com/releases/2012/05/120503125812.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. Video provided by Newsy
Powered by NewsLook.com
Condemned Man's US Execution Takes Nearly Two Hours

Condemned Man's US Execution Takes Nearly Two Hours

AFP (July 24, 2014) America's death penalty debate raged Thursday after it took nearly two hours for Arizona to execute a prisoner who lost a Supreme Court battle challenging the experimental lethal drug cocktail. Duration: 00:55 Video provided by AFP
Powered by NewsLook.com
Can Watching TV Make You Feel Like A Failure?

Can Watching TV Make You Feel Like A Failure?

Newsy (July 24, 2014) A study by German researchers claims watching TV while you're stressed out can make you feel guilty and like a failure. 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:
from the past week

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