基因決定友誼 好友緣分是天註定？

Research has shown that people tend to become friends with people similar to themselves. But now friendship is in our genes, scientists believe, with two friends sharing the some of the same DNA, while in other cases, friends have different versions of the same gene。

To find out if that theory holds water, James Fowler, a professor of medical genetics at the University of California and his colleague Nicholas Christakis at the Havard University culled data from two large studies which collected genetic information as well as data on friendship, marriage and other relationships. Then they tested the friendship pairs from the studies for six genes known to influence human behavior。

Of the six genes tested, the first involved a gene called DRD2 which affects how much pleasure we get from alcohol and cigarettes and other addictive substances. The study revealed that people with a version of the gene tend to befriend others with the same version. The opposite relationship was found for a gene called CYP2A6. Those with a version of the gene linked to having an "open" personality, gravitated to people with a different version of the gene, according to the Harvard University。

Christakis said that reasons for us being drawn to those who are genetically similar to ourselves include us being thrown together with people with similar interests in sports clubs or at university. But we may also actively seek out those who are like us – even if we are unaware of the underlying genetics. For instance, thin people may stick together, unaware that each member of the group lacks genes that make it easy for others to pile on the pounds. In terms of opposite attracting, we may hunt out people whose personalities complement our own. Extraverts may meet their quieter pals through work。曾有研究表明這世界確實是“物以類聚，人以羣分”。而如今科學家們有了新看法，那就是基因影響了我們的擇友方式，一般來說，兩個好朋友有一部分相同的基因，而在另外一些情況中，兩個朋友之間也可能具備同一基因的不同類型。

爲了驗證該看法是否可靠，加州大學醫學遺傳學教授詹姆斯•福勒和美國哈佛大學教授尼古拉斯•克里斯塔吉斯從爲美國兩個大型研究所收集的關於友情、婚姻、以及其他關係的基因數據中進行了揀選。隨後在每對好友身上對與人類行爲相關的6種基因進行了研究。

研究發現，6種基因中，首先發現的名爲DRD2的基因與人們從酒精和菸草及其他成癮物質中所能獲得的快感有着密切聯繫。攜帶該基因的人傾向於與同樣帶有此類型基因的人爲友。而另一種名爲CYP2A6的基因則爲“互補好友”找到了答案。哈佛大學的研究表明，攜帶有此種基因與“開放”式性格特點有關的人，往往會被具備此種基因的另一構型的人吸引。

克里斯塔吉斯教授表示，人們傾向於與具備相近基因的人爲友，也可以解釋爲什麼體育俱樂部或者大學裏興趣相投的人們會扎堆在一起。但即使不知道潛在的基因作用，我們也會主動尋找與自己相近的人。比如，體型清瘦的人往往會粘在一起，但他們並不會意識到他們自身都沒有容易讓自己長胖的那種基因。而就“互補好友”而言，我們可能會去尋找那些能和我們個性互補的人們做朋友。生性好動者在工作中易於與好靜者結成夥伴。