web analytics

Why Two Sisters Look So Different from Each Other?


Image credit: Worldwidefeatures.com

It is normal that siblings would have no resemblance to one another. However, when you first meet these two beautiful girls, you may find that they are totally different in their appearance. Actually it is amazing that they are not only sisters, but twins as well. In fact, you have to admit how fascinating genetics are.

With bright blue eyes, fair skin and red hair, the girl on the left is named as Lucy. On the right, it is Maria who has much darker skin with deep brown eyes and bouncy, black ringlets atop her head. The twin sisters are now turning to their eighteens, but when people see them, it is hardly believable that they are twins, because they look so differently. So people want to understand what the science is between this pair.

Donna, the twins’ mother, is half-Jamaican, and Vince, their father, is white. Now you would possibly know that these girls could not be identical twins. As a matter of fact, such things usually happen when a single sperm could fertilize an egg that would split into two genetically identical, but separate embryos in the following step. On the other hand, non-identical, or fraternal twins, are generally produced by the mother who would release two eggs at the same time, both of which would be fertilized by two different sperms. Instead of being genetically identical, their DNA are shared by fifty percent as normal siblings do.

The fact demonstrated between these girls is that Donna carries genes for both black and white skin, as a result, by chance Lucy finally inherited the genes for white skin, while Maria inherited the genes for black skin. Generally speaking, it is rare in such dramatic genetics, but it could be possible. In most cases, children would inherit the mixed features of their parents, like their siblings. However, in the example of these twins, each of them happened to inherit totally different features. In addition, as many British individuals are descendants of Afro-Caribbean, who are directly descended from white Europeans, so there is much chance to produce offspring with white skin.