Identical twins
Identical twins are monozygotic twins. They are formed from a single zygote or fertilized egg. The zygote splits into two parts and each part develops into an individual embryo. Their genetic origin is the same and therefore they have the same DNA.
Fraternal twins
Fraternal twins are dizygotic twins. They are formed from two eggs are fertilized by two different sperms. They share 50% of their genetic traits, just like any other sibling born at different times. Let us have a look at the differences between the identical and fraternal twins.
| Identical Twins | Fraternal Twins |
| A single zygote splits into two parts and develops into different embryos. | Two eggs are fertilized by two different sperms. |
| The genetic origin is the same and has the same DNA. | The twins share 50% of their genetic traits. |
| They are of the same sex. | The sexes may be the same or different. |
| They share the same blood type. | The blood types may or may not be the same. |
| They may or may not be dichorionic and diamniotic. | They are dichorionic and diamniotic. |
| Their personalities are complementary and dependent. | Their personalities may be similar or different. |
Also read: Determination of Sex
Sometimes the identical twins are physically connected. These are known as conjoined twins. There are two possibilities for the formation of conjoined twins- either the single fertilized egg does not split completely during the formation of identical twins, or two fertilized eggs fuse together earlier during the development. The fraternal and identical twins share some characteristics and forms of social behaviour. They share a very particular and special bond between them because they are born and brought up together. However, identical twins are not 100% similar. There are very minute differences which can’t be observed.
Recommended Video:
How Twins are Formed – Human Reproduction Class 12 Biology Concepts
Also read: Heredity
For more details on Differences Between Identical and Fraternal Twins and related topics, visit BYJU’S website or download BYJU’S app for further reference.
Comments