It's not uncommon for siblings to bear no resemblance to one another, but at first glance you may struggle to believe that these two beautiful girls, who appear to be polar opposites of one another, are not only sisters, but are in fact twins. Isn’t genetics fascinating?

As you can see, Lucy, the girl on the left, has fair skin, bright blue eyes and red hair. Maria, on the other hand, has much darker skin, deep brown eyes and bouncy, black ringlets atop her head. Understandably, the now 18-year-old sisters left a few jaws hanging when they popped out, and people rarely believe they are twins. So, what’s the science between this pair?

The girls’ mother, Donna, is half-Jamaican, whereas their father, Vince, is white. You’ve probably worked out by now that these girls cannot be identical twins. Those occur when a single sperm fertilizes an egg that subsequently splits into two genetically identical, but separate embryos. Non-identical, or fraternal, twins, on the other hand, are usually the result of the mother releasing two eggs at the same time, both of which become fertilized by two different sperms. Rather than being genetically identical, these share 50% of their DNA like normal siblings do.

What happened with these girls is that, thanks to Donna carrying genes for both black and white skin, by chance Lucy ended up inheriting the genes for white skin, whereas Maria inherited the genes for black skin. Such dramatic genetics are unusual, but possible. Most of the time, children will inherit a "blend" of their parents features - as was the case with their siblings. In the twins case, they each happened to inherit incredibly different features. Additionally, many British individuals with Afro-Caribbean heritage are directly descended from white Europeans, which raises the chance of producing offspring with white skin.