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: Identical twins can share more than identical genes

Related Stories

Identical twins can share more than identical genes

January 9, 2018
An international group of researchers has discovered a new phenomenon that occurs in identical twins: independent of their identical genes, they share an additional level of molecular similarity that influences their biological ...

Aggression in childhood: Rooted in genetics, influenced by the environment

December 20, 2017
Over the past few months, many local cases of assault and harassment have come to light and been widely discussed in the news, both here and in the U.S. and Europe. Why do people have these types of aggressive impulses? To ...

Hereditary facial features could be strongly influenced by a single gene variant, a new study finds

January 9, 2018
Do you have your grandmother's eyes? Or your father's nose? A new study by the Universities of Oxford and Surrey has uncovered variations in singular genes that have a large impact on human facial features, paving the way ...

Immune diseases inflict identical twins differently

December 13, 2017
Any parent with identical twins knows their two children are actually remarkably different. Identical twins are genetically identical, but they are not identical in gene expressions, a difference attributable to epigenetics. ...

Burn victim saved by skin grafts from identical twin (Update)

November 23, 2017
A man doomed to die after suffering burns across 95 percent of his body was saved by skin transplants from his identical twin in a world-first operation, French doctors said Thursday.

Twin study finds genetics affects where children look, shaping mental development

November 9, 2017
A new study co-led by Indiana University that tracked the eye movement of twins finds that genetics plays a strong role in how people attend to their environment.

Recommended for you

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

Can mice really mirror humans when it comes to cancer?

January 18, 2018
A new Michigan State University study is helping to answer a pressing question among scientists of just how close mice are to people when it comes to researching cancer.

Epigenetics study helps focus search for autism risk factors

January 16, 2018
Scientists have long tried to pin down the causes of autism spectrum disorder. Recent studies have expanded the search for genetic links from identifying genes toward epigenetics, the study of factors that control gene expression ...

Group recreates DNA of man who died in 1827 despite having no body to work with

January 16, 2018
An international team of researchers led by a group with deCODE Genetics, a biopharmaceutical company in Iceland, has partly recreated the DNA of a man who died in 1827, despite having no body to take tissue samples from. ...

The surprising role of gene architecture in cell fate decisions

January 16, 2018
Scientists read the code of life—the genome—as a sequence of letters, but now researchers have also started exploring its three-dimensional organisation. In a paper published in Nature Genetics, an interdisciplinary research ...

3 comments

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.