A new study published in the online edition of the journal Genome Research reveals that even though identical twins share the same womb, environmental factors unique to each twin influences their genetic activities.
The study was conducted by researchers at Murdoch Childrens Research Institute (MCRI) in Melbourne who analyzed the DNA in the placenta, umbilical cords and cord blood of a group of identical and non-identical twins and found that while the DNA sequence was the same in identical twins, the chemical markers necessary to switch the genes on and off were different.
"It's been known for some time that identical twins - twins with the same DNA sequences - can look different, can behave different and can have different health conditions. In rare cases this can be down to genetic differences but it can't explain everything. This must be due to events that happened to one twin and not the other whilst in the womb", lead researcher Jeff Craig said.