He's also one of the principal investigators of the twin study.

他也是双生子研究主要研究者之一。

The doppelganger? -Evil twin shadow person.

二重身？-不详神秘双生者。

This is an example of twinning or gemination. Here are some more examples.

这是孪生或双生一个例子。 这里还有一些例子。

One of the hugely surprising findings from behavioral genetics is how alike identical twins reared apart are.

行为遗传学一个巨大惊奇发现是， 即使是被分开教养同卵双生子也是多。

Thanks to research like NASA's twin study which you'll hear about in a minute, scientists are getting an idea about how extended time in space effects people.

多亏了下面即将介绍美国航天局双生子研究，科学家们正在了解长时间在太空中生活对人类影响。

For instance, monozygotic twins look more alike than dizygotic twins and maybe they have different and--they have more similar environments because of this similarity in appearance.

比如， 单卵双生子貌更， 可能是因为他们有着不同、更环境。