People often make the mistake of taking twins to mean that individuals that are born twins are exact copies of one another. Twins are almost always presumed to have similar physical characteristic and attributes, have similar behavioral patterns and have the same finger prints. On the contrary, twins are not clones of each other but separate and distinct persons.
They are generally two types of twins. There are Identical Twins and Fraternal (Non-Identical) Twins. Surprisingly, identical twins are something of a rarity, with a likelihood of about one in three.
The Difference Lies in the Zygosity
The distinction between identical from fraternal does not depend on how closely twins resemble each other but rather in the manner in which they are formed. Zygosity refers to the genetic relationship between multiples or simply put the “similarity between the genomes of each twin”. Zygosity will tell you whether twins are identical or fraternal.
Identical Twins
The scientific term for Identical Twins is Monozygotic, wherein mono means one and zygote means fertilized egg. This means that identical twins are formed from a single fertilized egg which later splits into two. Twins that are identical will roughly have the same combination of cells as well as a similar genetic origin. Identical twins will always be of the same sex. Identical twins look very much alike and sometimes may be very difficult to tell apart.
Fraternal Twins
Fraternal twins on the other hand are Dizygotic. This entails that two eggs were fertilized by two separate sperms. Fraternal twins are about as genetically similar are regular siblings which is about 50% similarity. Fraternal twins may look alike just how any brother or sister would. Additionally, fraternal twins may either be born of the same sex or be one boy and one girl. Dizygotic twinning runs in the family and may be easily inherited.
How to Identify Identical Twins From Fraternal Twins?
Identical twins may be spotted as early as being in the womb because they are often found sharing a single placenta. Once they are born, identical twins are found to be of the same sex and physically look much alike.
Fraternal twins may be identified when one twin if found to be a by while the other is a girl. Moreover, other ways to find out whether twins are fraternal is to look at their blood type. Fraternal twins have different blood types yet the most definitive way to find out whether twins are identical or fraternal is by genetic testing.
