Following are the differences between the development of a single baby, identical twins and fraternal twins.
Lets start with a single baby.
let’s go back to the beginning when fertilization occurs, here you see the egg cell is fertilized by a single sperm cell to form a zygote. Over the next few days the fertilized egg cell divides over and over to form a structure composed of hundreds of cells called a blastocyst.
During the first week after fertilization, we can look inside the blastocyst and see the massive cells that will form the embryo. The blastocyst will continue traveling toward the uterus where it will implant in the uterine lining and grow into a single baby.
Let’s discuss the development of identical twins.
Identical twins start out from a single fertilized egg cell or SCI goat which is why they’re also called monozygotic twins like the single baby, we just saw the egg is fertilized by a single sperm cell unlike the single baby.
This fertilized egg cell will split into two separate embryos and grow into identical twins, this remarkable event takes place during the first week after fertilization and can happen at several different times at the two cell stage on day two.
At the early blastocyst stage on day four or in the late blastocyst stage. On day six the stage at which the egg cell splits determines how the twins will implant in the uterine lining and whether or not they share in amnion Corian and placenta.
Basically the earlier the splitting occurs the more independently the twins will develop in the uterus, so a pair of identical twins that split during the two cell stage will each develop its own amnion Corian and placenta twins that split during the late blastocyst stage will share an ambien core young and placenta.
A common misconception about the conception of identical twins is that the trait for having them is passed on to future generations through the mother’s genes but the truth is science doesn’t know the reason why identical twins occur at this time.
We can just say that there are examples of a nine-month double miracle.
Finally let’s take a look at the second type of twins non identical or fraternal twins.
Develop from two fertilized egg cells or zygotes which is why they’re also called dizygotic twins.
Unlike identical twins however fraternal twins are definitely influenced by the mother’s genes here’s why when the mother of fraternal twins ovulates sometimes our ovaries release two egg cells for fertilization.
Typically only one egg cell is released during ovulation during conception both of these egg cells become fertilized by two different sperm cells which is why fraternal twins don’t look exactly alike sometimes they’re not even the same sex here in the uterus you can see that the twin embryos developed separately each having his or her own chorion onion and placenta.