Identical Twins Can Be Different

Did you know that Connecticut and Washington D.C. have the highest number of twin births in the United States? Did you know that there are towns and villages around the world that have a much higher number of twins than anywhere else? These twin towns are found in Africa, Europe, Asia and South America. Twins can be fraternal in which there are two different fertilized eggs or identical twins that come from a single fertilized egg that splits into two during early development. This means that the identical babies share many of the same characteristics.

Identical twins that were once thought to be exactly the same, are actually not as identical according to some scientific discoveries. New research proves that the twins are actually born with slight differences in their DNA. Before this, scientists and scholars believed that differences between identical twins were caused by what happened to their bodies after they were born.

A team of researchers from Iceland looked more minutely into the differences between identical twins’ genes. They studied the DNA of 387 pairs of twins, their parents, children and spouses. This helped them to track their DNA from an earlier point. These researchers found that after an egg split each twins’ genes could go through separate changes known as mutations. These different mutations could separate the twins from each other well before they are born.

Mutations could cause one twin to be taller than the other or make one more prone to certain diseases. The above study also found that identical twins have an average of 5.2 mutations, but some can have as many as 100 genetic differences.

This study has been an eye opener in the scientific field because many past studies have been based on the idea that identical twins are born with exactly the same matching genes, and if two twins were raised separately and had different behaviours and disorders it was assumed this was because of their different life experiences.

Kari Stefansson, a co-author of the new study said that it would now be more accurate to call identical twins “monozygotic twins”- twins that come from the same zygote (a fertilized egg), rather than identical twins.

Bibliography:

The week Junior: February 19, 2021.Vol 2, Issue 45, Page14 “Identical twins can be different” Science and Technology.