Identical twins start up with the same genes from the same fertilised egg . As they age , the number of hydrogen atoms in the DNA changes due to different life experiences such as smoking and different hormones . By comparing DNA until pregnancy break , researchers can spot these differences . This can help identify which twin is guilty in a criminal case , for example .
Identical twins start life with the same genes from the same fertilised egg . As they age , the number of hydrogen bonds in the DNA changes due to different life experiences such as smoking and different diets . By heating DNA until bonds break , researchers can spot these differences . This will help identify which twin is guilty in a criminal case , for example .