Which term describes twins who develop from a single fertilized egg that splits, resulting in two individuals who share the exact same DNA?

Which term describes twins who develop from a single fertilized egg that splits, resulting in two individuals who share the exact same DNA?

• A. Fraternal twins
• B. Identical twins
• C. Monozygotic twins
• D. Dizygotic twins

Answer: (B)

This question is about how twins form and how much DNA they share. When a single fertilized egg splits into two embryos, the result is identical twins, also called monozygotic twins. Because they come from the same zygote, they start with the same genetic material, so their DNA sequences are essentially the same. This is in contrast to fraternal (dizygotic) twins, who arise when two separate eggs are fertilized by two sperm and are genetically no more alike than typical siblings. While there can be tiny differences due to mutations after the split or epigenetic changes, the defining idea is that identical twins originate from one fertilized egg and share the same DNA.

This question is about how twins form and how much DNA they share. When a single fertilized egg splits into two embryos, the result is identical twins, also called monozygotic twins. Because they come from the same zygote, they start with the same genetic material, so their DNA sequences are essentially the same. This is in contrast to fraternal (dizygotic) twins, who arise when two separate eggs are fertilized by two sperm and are genetically no more alike than typical siblings. While there can be tiny differences due to mutations after the split or epigenetic changes, the defining idea is that identical twins originate from one fertilized egg and share the same DNA.