Answer:
Identical twins are the result of fertilization of a single egg by a single sperm.
Explanation:
Identical twins are also called monozygotic or univiteline and account for approximately 30% of cases of double pregnancies. They are the result of the fertilization of a single egg by a single sperm whose zygote in early pregnancy is divided into two (or more), each settling in a different region of the uterus. Because of this fact is that univiteline twins are extremely similar and always are of the same sex.
Identical twins are exactly the same, right? After all, they come from a single fertilized egg, which contains a group of genetic instructions, or genome, formed by combining the father's chromosomes with the mother's.
But experience shows that identical twins are rarely completely equal. Until recently, any differences between twins were largely attributed to environmental influences (also known as “creation”). However, recent studies show that in some cases the DNA of a twin was different from that of his brother at various points in the genome. At these sites of genetic divergence, one had a different number of copies of the same gene, a genetic state called copy number variants.
