What mechanisms control handedness and keep left-handedness rare?

是什么机制控制了用右手或左手的习惯并使左撇子很少出现？

youdao

Sporting advantage notwithstanding, therefore, the existence of left-handedness poses a problem for biologists.

因此，尽管具有体育优势，左撇子的存在给生物学家提出了一个问题。

youdao

Sporting advantage notwithstanding, therefore, the existence of left-handedness poses a problem for biologists.

因此，尽管具有体育优势，左撇子的存在给生物学家提出了一个问题。

youdao

They looked at homicide-rates and the frequency of left-handedness, and found they appeared to be linked.

BBC: NEWS | Health | Left-handers 'better in fights'

But the Eipo had around three homicides per 1, 000 people and a left-handedness rate of 20%.

BBC: NEWS | Health | Left-handers 'better in fights'

But that raises a further question: if left-handedness is beneficial, then why is it so rare?

ECONOMIST: Why some snails are left-handed