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奇怪的荒原的寄生双胞胎& # 038双嵌合

发布时间:2018-09-17 11:34 作者:admin 来源: 点击: 字号:

So you perhaps thought that 大发体育twins could be either identical or fraternal? But did you know that there are actually other types of twins besides these two mentioned? Of course, identical and fraternal twins are the ones we are more aware of because they are the ones we hear about most and are most likely to encounter。

The chances of having identical twins are of around 3 in every 100 births。 When it comes to fraternal twins the chances are higher and are in fact around double。 The incidence rate of twin births does vary from culture to culture *** country to country。 Twin DNA testing, available by a number of laboratories and companies including International Biosciences, is used to confirm whether twins are monozygotic or dizygotic and people sometimes seek a twin zygosity test prior to a blood transfusion or organ transplant (this is because identical twins make ideal donors to each other due to their same antigens)。 Whichever the case, twin births are far from common。 But there are even rarer types of twins that you might not even have ever heard of。 Let’s take a look at two very interesting, if not fascinating, twin phenomena。

Twin Chimerism

Illustration: Maggie Koerth-Baker , BoingBoing

Illustration: Maggie Koerth-Baker , BoingBoing

We always think of twins as two separate individuals irrespective of whether they are identical or fraternal; this might seem like stating the obvious。 There is however a phenomenon, rare in animals but rarer in a humans, that is called twin chimerism that defies the idea of twins being two separate individuals。

When we look at how twins are brought into the world we probably all know the following two basic facts:

  • Identical twins: these are the result of a sperm cell fusing with an egg。 The fertilized egg later divides into two and forms two new individuals。 Each of these new individuals came about from the same egg and therefore, each has the exact same copy of genetic material。
  • Non identical twins: These result from two sperm cells fertilizing two eggs resulting in two new individuals。 Each individual carries its personal genetic makeup due to the fact that they were formed from a different sperm cell and egg, each carrying its own genetic material。

本文源自: 环亚娱乐

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