How do Monozygotic twins differ from Dizygotic twins?

• A. They come from separate fertilized eggs
• B. They share 100% of their genes
• C. They develop more similar personalities
• D. They always exhibit 100% identical physical traits

Answer: (B)

Monozygotic twins, also known as identical twins, originate from a single fertilized egg that splits into two embryos. This genetic identicality means that they share 100% of their genes, which is why they often have very similar physical characteristics and can have comparable personality traits as they develop in the same environment.

In contrast, dizygotic twins, or fraternal twins, develop from two separate fertilized eggs and share approximately 50% of their genes, just like any other siblings. This genetic difference accounts for the greater variability in traits and characteristics among dizygotic twins compared to monozygotic twins.

Although monozygotic twins can potentially exhibit closely aligned personalities due to their shared genetics and upbringing, it is not a certainty that they will have identical personality traits. Similarly, while they may look very similar, they may not always exhibit 100% identical physical traits, as environmental factors, individual experiences, and other influences can lead to variations even amongst them.

Thus, the most accurate distinction between these two types of twins is that monozygotic twins share 100% of their genes.