Identical twins don’t always have identical DNA, but identical twins differ by an average of 5.2 genetic changes, according to a new report published Jan. 7 in Nature Genetics, reported by Science News, according to a new study. This study goes against the belief that identical twins are genetically identical, which was often the basis for the idea that differences in health between twins are a result of their environment. This new study shows that genetics may have more to do with it than previously believed.
“Imagine you have identical twins who are raised separately,” CEO and founder of DeCode Genetics and study co-author Kari Stefansson told CNN. “If one of them developed autism, the classic interpretation is that it is due to environmental factors. But our work shows that before concluding that it is caused by the environment, you need to sequence the genome of twins to find out what could explain autism. Stefansson said this “divergence of mutations” could be the cause of “devastating childhood illnesses” such as epilepsy and metabolic disorders. She also said that a large percentage of “these horrific syndromes of very early childhood are due to genomic mutations.” Identical twins, also known as monozygotic twins because they come from a single fertilized egg. , as reported by Science News, are often studied to determine the origin of specific traits, diseases or conditions, either the result of genetics or the result of their environment. In particular, this study looked at 381 pairs of identical twins and found that 38 of the pairs had identical genetics, but most of the pairs had DNA differences that appeared very early in their development.
Thirty-nine of the pairs had more than 100 changes between the twins and the study suggests that these DNA differences occur when the embryo separates to form two early in development or shortly after the division is split. embryo. This suggests that this embryo division is not as sharp or sharp as previously thought, resulting in the DNA changes observed.
Some twins occur when a single cell or a small group of cells separate from the embryo, Science News notes, and it’s the number of cells a twin comes from that can determine the genetic differences between it and its other twin. The more uneven the divisions of the embryo, the greater the number of genetic differences between twins.
“This is an extraordinary, exciting and insightful effort to identify the first cellular mechanisms that explain the genetic differences between MZ (monozygotic) twins,” California State University, Fullerton, professor of psychology, Nancy, told CNN Segal. “It is well known that MZ co-twins do not bear a perfect resemblance and that some differences may reflect genetic differences. The present study offers new insight into the source of the MZ co-twin differences. “According to Segal, the study shows that “some twin models underestimate the genetic effects and require revision.”
For more twins, check out our list of the best movie twins of all time, and if you’re looking for more DNA science, read this story on how a new study finds most Vikings were neither blond or blue eyed.
Wesley LeBlanc is a freelance news writer and guide for IGN. You can follow it on Twitter @LeBlancWes.