Do Identical Twins have the Same DNA
In a 2021 study [5], 15% of pairs of identical twins may have a member who shows a significant genetic difference from the other twin.
In the laboratory investigation, researchers sought to determine the normal frequency of genetic mutations leading to DNA differences in monozygotic twins. They discovered a median of 14 post-zygotic mutations that varied between a pair of twins among the 381 twin pairs they examined. Still, there were differences: 39 twin pairs had genetic differences of over 100 mutations, while 38 pairs had no differences at all.
Given the widespread belief that identical twins are genetically indistinguishable, even though the average number of genetic mutations resulting in DNA differences between identical twins may be minor, it’s still a significant discovery.