Identical twins not as identical as believed

February 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: Expecting twins or triplets? What you should know before they arrive

Related Stories

How our cells use mother's and father's genes

September 28, 2016

Researchers at Karolinska Institutet and Ludwig Institute for Cancer Research have characterized how and to what degree our cells utilize the gene copies inherited from our mother and father differently. At a basic level ...

Mother uncovers lasting impact of baby son's organ donation

September 25, 2016

An ultrasound showed one of Sarah Gray's unborn twins was missing part of his brain, a fatal birth defect. His brother was born healthy but Thomas lived just six days. Latching onto hope for something positive to come from ...

Mapping the 'dark matter' of human DNA

October 7, 2016

Researchers from ERIBA, Radboud UMC, XJTU, Saarland University, CWI and UMC Utrecht have made a big step towards a better understanding of the human genome. By identifying large DNA variants in 250 Dutch families, the researchers ...

Recommended for you

Scientists find new genetic roots of schizophrenia

October 19, 2016

UCLA scientists have made a major advance in understanding the biology of schizophrenia. Using a recently developed technology for analyzing DNA, the scientists found dozens of genes and two major biological pathways that ...

Possible miscarriage gene found: study

October 19, 2016

Scientists said Wednesday they had linked mutations in a specific gene with an increased risk of recurrent miscarriages, offering hopes of better diagnosis and treatment for affected women.


Adjust slider to filter visible comments by rank

Display comments: newest first

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.
1 / 5 (1) Feb 16, 2008
Indeed googleplex. My thoughts exactly.
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.