What is a characteristic of Monozygotic twins?

• A. They share 50% of their genes
• B. They are not identical
• C. They share 100% of their genes
• D. They develop in two separate fertilized eggs

Answer: (C)

Monozygotic twins, commonly known as identical twins, originate from a single fertilized egg that splits into two embryos. This means that they share 100% of their genetic material because they come from the same zygote. The genetic uniformity between monozygotic twins is a key feature that allows researchers to study the impact of genetics versus environment on various traits and behaviors.

In contrast, other types of twins, such as dizygotic twins, arise from two separate eggs fertilized by two different sperm, resulting in only 50% genetic similarity. Additionally, the concept of monozygotic twins inherently implies that they are indeed identical, which further cements the correctness of the statement about their genetic sharing.