What causes identical twins to form
To form fraternal or dizygotic twins, two eggs (ova) are fertilised by two sperm and produce two genetically unique children.An ongoing study of twins at king's college in london has found that the many surprising differences in the lives of identical twins are largely due to the effects of a biological mechanism known as epigenetics.Identical twins start out as a singleton pregnancy, and are also known as monozygotic twins.When identical twins form in utero, one fertilized egg, called an embryo, splits into two separate individuals.However, there are two theories about the possible causes of conjoined twins.These twins are the same sex and share the same genes.
Despite a common environment and identical genes, the mice showed highly individual patterns of behavior.Monozygotic multiples form from a single zygote (fertilized egg) that splits after fertilization.One fertilised egg divides and split into two separate babies.Because the two embryos are the result of a single egg/sperm combination, they have the same genetic origins.The main theory for conjoined twins is that this splitting process isn't complete.
