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

他也双生主要者之一。

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.

这孪生或双生一个例。 这里还有一些例。

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， 即分开教养同卵双生也多么相似。

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，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， 单卵双生相貌更相似， 可能因为他们有着不同、更相似环境。