时差N小时:表亲结婚风险 Marriage between first cousins

Fans of classic movies will remember the famousdueling banjos scene in Deliverance, the story offour city friends who take an ill-fated boating tripdown a backwoods Georgia river.

经典电影的粉丝们不会忘记激流四勇士中著名的班卓琴对决场面,这部电影讲述的是四位都市好朋友乘着独木舟沿着未开垦乔治亚河命运多舛的冒险之旅。

As the friends set out, one of the friends challenges alocal boy with a banjo to see who can play faster.

随着他们旅程的进行,其中一位好朋友用班卓琴挑战一个当地小男孩,看谁弹奏更快。

At the end of the song the camera zooms in to reveal the boy's diseased, inbred features.

一曲终了之时随着镜头拉近小男孩的天然病态特征暴露无遗。

Such images have contributed to the taboo against marriage between first cousins.

这些影像已经说明了表亲结婚导致的禁忌。

Geneticists explain that since closely related personsare more likely to harbor identical genetic mutations, their children have a greater chance ofbeing born with defects.

遗传学家解释因为血缘密切相关的人更有可能产生基因突变,他们的孩子有更大可能的先天缺陷风险。

But such risks might be overstated.

但是这样的危险可能有些言过其实。

According to one study, children from first cousin marriages are only 1.7 to 2.8 percent morelikely to be born with serious birth defects than children of conventional marriages.

据一项研究称,相比传统婚姻表亲结婚生出的孩子仅1.7—2.8%的几率更可能出现天生的严重生理缺陷。

Although the risk is still significant, it is lower than previously thought.

虽然风险仍然可观,但这比之前所认为的更低。

Prolonged interbreeding in any species can eventually lead to serious birth defects.

任何物种的长时间异血缘交配最终都会造成严重的生理缺陷。

Harmful genetic mutations are less likely to appear in large populations where individualsreproduce with random partners due to the wider variety of genetic mutations.

有害的基因突变不太可能出现在由于广泛的遗传变异个体间与随机伴侣繁衍的大群体中。

But in small, isolated populations where inbreeding is common,

但在小型,隔离的群体中,近亲繁殖很常见,

there's a greater chance that related partners carry the same mutations.

所以相关伴侣携带相同基因突变有更大的几率。

But harmful effects are more common in groups with a history of interbreeding over severalgenerations.

但有群体异血缘交配史的几代人有害影响更为常见。

First cousins that are not from such groups run only a slightly greater risk of producingchildren with birth defects than non-related couples.

表亲不属于这样的群体，只比结婚夫妇要承担略大产生缺陷儿童的风险几率。

Although such risks should not be ignored,

虽然这样的风险不容忽视,

first cousin marriage is not necessarily a recipe for genetic disaster.

但表亲婚姻不一定会导致基因灾难。