DNA is a like a fingerprint. It is very unique. For this reason, it often becomes the center of criminal cases and serves as rock-solid evidence for prosecutors.
However, DNA is not without its flaws. One particular issue is that most people have distinct DNA that nobody else in the world has, except for identical twins. They have the exact same DNA profile. If a case involves identical twins and DNA evidence, it could raise some reasonable doubt. But that may be changing.
Not 100% the same
While identical twins have identical DNA, there are some microscopic differences. Standard testing procedures do not have the ability to pick up on these variations, which is why in many cases, having an identical twin could introduce reasonable doubt.
However, because of the fact there is a DNA difference, technology is advancing to help decipher between this seemingly identical DNA.
A different sequencing
A newer technology called massive parallel sequencing can map out the DNA to a point where it can find those minute distinctions, which the scientific world calls mutations. Mutations occur naturally, and when they happen to only one twin, it provides a unique identifier.
While this next-generation sequencing is available, it is not readily available. What this means is that in most cases, there is not going to be the option to run the evidence through massive parallel sequencing because it simply will not be an option. So, in many cases, being an identical twin could be a great defense against seemingly indisputable DNA evidence.