Featured Research

from universities, journals, and other organizations

Identical Twins Not As Identical As Believed

Date:
February 20, 2008
Source:
University Of Alabama
Summary:
Contrary to our previous beliefs, identical twins are not genetically identical. This surprising finding may be of great significance for research on hereditary diseases and for the development of new diagnostic methods. How can it be that one identical twin might develop Parkinson's disease, for instance, but not the other? Until now, the reasons have been sought in environmental factors. The current study complicates the picture.

Contrary to our previous beliefs, identical twins are not genetically identical.
Credit: istockphoto/Andi Berger

Contrary to our previous beliefs, identical twins are not genetically identical. This surprising finding may be of great significance for research on hereditary diseases and for the development of new diagnostic methods. How can it be that one identical twin might develop Parkinson's disease, for instance, but not the other? Until now, the reasons have been sought in environmental factors. The current study complicates the picture.

The researchers studied 19 pairs of monozygotic, or identical, twins and found differences in copy number variation in DNA. Copy number variation (CNV) occurs when a set of coding letters in DNA are missing, or when extra copies of segments of DNA are produced.

Humans receive one chromosome from their mother and one from their father, providing for two copies of the genome. In some cases, bits of DNA are missing from a chromosome, leaving the offspring with just one copy of that bit of DNA. In other instances, mutations may produce three, four or more copies of a particular bit of DNA. In most cases, variation in the number of copies likely has no impact on health or development. But in others, it may be one factor in the likelihood of developing a disease.

Researchers at UAB( University of Alabama), Leiden University Medical Center and VU University, The Netherlands; and Uppsala University and Karolinska Institutet, Sweden recently published their findings.*

“The presumption has always been that identical twins are identical down to their DNA,” said Carl Bruder, Ph.D. and Jan Dumanski, Ph.D., of UAB’s Department of Genetics and the study’s lead authors. “That’s mostly true, but our findings suggest that there are small, subtle differences due to CNV. Those differences may point the way to better understanding of genetic diseases when we study so-called discordant monozygotic twins….a pair of twins where one twin has a disorder and the other does not.”

Bruder points out that one twin might develop a particular disease…Parkinson’s, for example…while the other does not. Previously, it was thought that environmental factors were the likely culprits, not genetics. Bruder and Dumanski think their findings indicate that CNV may play a critical role and this can be efficiently studied in identical twins.

“More importantly, changes in CNV may tell us if a missing gene, or multiple copies of a gene, are implicated in the onset of disease,” Bruder said. “If twin A develops Parkinson’s and twin B does not, the region of their genome where they show differences is a target for further investigation to discover the basic genetic underpinnings of the disease.”

The UAB lab is one of the few worldwide that can make the full genome BAC (bacterial artificial chromosome) arrays that are used to find the changed DNA regions.

The findings were published Feb. 14 online in the American Journal of Human Genetics.http://eproofing.dartmouthjournals.com/pdfproofing/ajhg0069r.pdf

The research was funded by support from UAB, the Swedish Cancer Society, the Swedish Children’s Cancer Foundation, the U.S. Army Research and Material Command, National Institutes of Health, The Netherlands Genomics Initiative and the National Institutes of Health.


Story Source:

The above story is based on materials provided by University Of Alabama. Note: Materials may be edited for content and length.


Cite This Page:

University Of Alabama. "Identical Twins Not As Identical As Believed." ScienceDaily. ScienceDaily, 20 February 2008. <www.sciencedaily.com/releases/2008/02/080215121214.htm>.
University Of Alabama. (2008, February 20). Identical Twins Not As Identical As Believed. ScienceDaily. Retrieved September 2, 2014 from www.sciencedaily.com/releases/2008/02/080215121214.htm
University Of Alabama. "Identical Twins Not As Identical As Believed." ScienceDaily. www.sciencedaily.com/releases/2008/02/080215121214.htm (accessed September 2, 2014).

Share This




More Health & Medicine News

Tuesday, September 2, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

U.N. Says Ebola Travel Restrictions Will Cause Food Shortage

Newsy (Sep. 2, 2014) The U.N. says the problem is two-fold — quarantine zones and travel restrictions are limiting the movement of both people and food. Video provided by Newsy
Powered by NewsLook.com
Get on Your Bike! London Cycling Popularity Soars Despite Danger

Get on Your Bike! London Cycling Popularity Soars Despite Danger

AFP (Sep. 1, 2014) Wedged between buses, lorries and cars, cycling in London isn't for the faint hearted. Nevertheless the number of people choosing to bike in the British capital has doubled over the past 15 years. Duration: 02:27 Video provided by AFP
Powered by NewsLook.com
Can You Train Your Brain To Eat Healthy?

Can You Train Your Brain To Eat Healthy?

Newsy (Sep. 1, 2014) New research says if you condition yourself to eat healthy foods, eventually you'll crave them instead of junk food. Video provided by Newsy
Powered by NewsLook.com
We've Got Mites Living In Our Faces And So Do You

We've Got Mites Living In Our Faces And So Do You

Newsy (Aug. 30, 2014) A new study suggests 100 percent of adult humans (those over 18 years of age) have Demodex mites living in their faces. 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