It's sort of like their family mem-bers. And in fact the number of genes they share in common is so large. And that is almost that they share a common ancestor. It's like their fourth cousins.
The friends were most alike when it came to their sense of smell but the study suggests that we could be drawn to people with similar traits because it helps us to survive.
If you are the first person that has a mutation and you don’t have any friends， you need surround yourself with other people who also have that trait. This is not just the case that people with the best trait， it’s the people we have similar genes so they are friends.
When it comes to our immunities though， the friends'genes were more different than that of the strangers. The scientists say this trend could also give us an evolutionary edge though because if your friends can fight different diseases than you；you are less likely to spread infections. It gives a new meaning perhaps to being their bio-friends.
譯文：
在選擇朋友時，我們的選擇其實大部分是由基因決定的。和陌生人相比，我們和朋友在遺傳學上更加相似。
主題轉向講述好朋友之間故事的90年代情景喜劇《老友記》。劇中兩位主角有血緣關係，但如果這些人在現實生活中也是朋友的話，他們在生物學上的親近關係相當於表親。加利福尼亞大學研究人員分析了2000人左右的基因變異，同時，將沒有血緣關係的朋友和沒有血緣關係的陌生人比較。他們發現，朋友比陌生人平均多出0.1%的共同DNA，數據雖小，意義卻很大。
這有點像是親屬關係。實際上，他們擁有的相同基因數量很大，幾乎相當於他們擁有同一個祖先，互為第四代表親。
朋友之間擁有相似的嗅覺。研究表明，我們容易接近擁有相似特質的人，因為這有助於我們生存。
如果你是第一個擁有一種突變的人，而且你沒有朋友，那麼你身邊需要相同特質的人。不是說身邊要有最好特質的人，而是要擁有相似的基因，才能成為朋友。
和陌生人相比，朋友之間的免疫性更加不同。但科學家說，這個趨勢可以為我們的進化增加優勢，因為如果你的朋友們比你更能抵抗各種疾病，那麼你傳播傳染病的機率就會小很多。也許這能為“生物學朋友”增加新的意義。
單詞解析Word analysis
1. gene[d?in]n.基因，遺傳因子
例句：As we all know， we are the product of our genes.
如我們所知，我們是由基因產生的。
2. bunch[b?n(t)?]n.群；串；束
例句：A bunch of red roses drip their golden scent.