Identical twins not as identical as believed

Feb 15, 2008

Contrary to our previous beliefs, identical twins are not genetically identical. This surprising finding is presented by American, Swedish, and Dutch scientists in a study being published today in the prestigious journal American Journal of Human Genetics. The 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.

“Even though the genome is virtually identical in identical twins, our results show that there in fact are tiny differences and that they are relatively common. This could have a major impact on our understanding of genetically determined disorders,” says Jan Dumanksi, who co-directed the international study with his colleague Carl Bruder.

“By uncovering these small genetic differences in identical twins where one of them is sick, we have a way of tying specific genetic changes to the genesis of common diseases,” says Carl Bruder.

These researchers studied 19 pairs of identical twins and found that they indeed had the same DNA but nevertheless evinced differences in the number of copies of individual DNA segments. A segment might be missing, or more copies might exist in one twin. This could explain how one identical twin can be afflicted with a disorder while the other twin remains fully healthy, according to the scientists.

Source: Uppsala University

Explore further: Nationwide project paves way for clinical genetic diagnosis

add to favorites email to friend print save as pdf

Related Stories

Fogo volcano on Sentinel's radar

Dec 03, 2014

Radar images from the Sentinel-1A satellite are helping to monitor ground movements of the recently erupted Fogo volcano.

Team develops cognitive test battery for spaceflight

Nov 26, 2014

Space is one of the most demanding and unforgiving environments. Human exploration of space requires astronauts to maintain consistently high levels of cognitive performance to ensure mission safety and success, and prevent ...

How mutualisms evolve in a world of selfish genes

Nov 11, 2014

Reproduction for a female fig wasp can be a nightmarish process. When she is ready to lay her eggs, she leaves the fig in which she was born and became pregnant and searches for another. After she finds it, ...

A timeline of deep-space comet encounters

Nov 10, 2014

12th November 2014. That is the date in which Rosetta, led by the European Space Agency, will release its lander Philae to touchdown on Comet 67P/Churyumov-Gerasimenko in outer space.

Notorious hacktivist shares methods, motives

Nov 10, 2014

Cocaine dealers, bank robbers and carjackers converge at Manchester Federal Prison in rural Kentucky—and then there is Jeremy Hammond, a tousle-haired and talented hacker whose nimble fingers have clicked ...

Recommended for you

Nationwide project paves way for clinical genetic diagnosis

21 hours ago

The first nationwide project to genetically diagnose rare diseases will pave the way for translating advances in genomics into patient care in the NHS. Deciphering Developmental Disorders (DDD), a collaboration between the ...

User comments : 3

Adjust slider to filter visible comments by rank

Display comments: newest first

googleplex
3 / 5 (3) Feb 15, 2008
Ok the infamous Physorg bogus headline strikes again.
It should say "indentical twins used to find disease genotypes".
It is implicit in what the article says that 'theoretically ideal' identical twins have genetically identical DNA. However in practice mutations can occur to one twin that cause small differences. In some instances this can be used to identify disease genotypes.
gopher65
1 / 5 (1) Feb 16, 2008
Indeed googleplex. My thoughts exactly.
superhuman
not rated yet Feb 25, 2008
No, the title is correct. The article says that there are more differences between homozygous twins then there should be according to our current knowledge.
And "indentical twins used to find disease genotypes" is no news its been like that for decades.

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.