美国科学60秒 SSS 2013-02-19（在线收听）

 　　This is scientific American's science 60 second science, I am steve mosbyA lot of people have had compacted third molars. Third molars produce chronic pain. Allen man, a Princeton University Physical anthopolegist, the annual meeting of the immagrate association for the advanced science in boston on Feb 15th, Some thousands of years ago, there were a round of mutation, It was pressed the calcification of the third molor of wisdom. So many of you,  many of your children, have grown to adult with ad-period the third molars. Now that particular mutation has XX frenquency, so that some population more than 40% of people have one of more abs third molars. So you might ask the question: how did that develop because obviously you have the compact third molar if you follow survive of the XX  then you are not gonna fall over folding your mouth and dying in agony.  Reproduction of the fitis is  what is all about, in other words, differential reproduction how will this work well.  In the evening person who has had serious chronic pain with impact third moloar pephaps lower third molors, impacting into the multipulate conon causing a lot of pain, the company come up and says: how about we reproduction here. and the person says: not tonight dear my chew is killing me. That is effect in evolutional senorio. Becaus that will produce fewer all spring in those people that frenquency of this feature would increase over time. Thanks for the munite for scientific american's 60 second science.