時差N小時:表親結(jié)婚風(fēng)險 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.

經(jīng)典電影的粉絲們不會忘記激流四勇士中著名的班卓琴對決場面,這部電影講述的是四位都市好朋友乘著獨(dú)木舟沿著未開墾喬治亞河命運(yùn)多舛的冒險之旅。

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

隨著他們旅程的進(jìn)行,其中一位好朋友用班卓琴挑戰(zhàn)一個當(dāng)?shù)匦∧泻?看誰彈奏更快。

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

一曲終了之時隨著鏡頭拉近小男孩的天然病態(tài)特征暴露無遺。

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

這些影像已經(jīng)說明了表親結(jié)婚導(dǎo)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.

遺傳學(xué)家解釋因為血緣密切相關(guān)的人更有可能產(chǎn)生基因突變,他們的孩子有更大可能的先天缺陷風(fēng)險。

But such risks might be overstated.

但是這樣的危險可能有些言過其實。

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.

據(jù)一項研究稱,相比傳統(tǒng)婚姻表親結(jié)婚生出的孩子僅1.7—2.8%的幾率更可能出現(xiàn)天生的嚴(yán)重生理缺陷。

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

雖然風(fēng)險仍然可觀,但這比之前所認(rèn)為的更低。

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

任何物種的長時間異血緣交配最終都會造成嚴(yán)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.

有害的基因突變不太可能出現(xiàn)在由于廣泛的遺傳變異個體間與隨機(jī)伴侶繁衍的大群體中。

But in small, isolated populations where inbreeding is common,

但在小型,隔離的群體中,近親繁殖很常見,

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

所以相關(guān)伴侶攜帶相同基因突變有更大的幾率。

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

但有群體異血緣交配史的幾代人有害影響更為常見。

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

表親不屬于這樣的群體，只比結(jié)婚夫婦要承擔(dān)略大產(chǎn)生缺陷兒童的風(fēng)險幾率。

Although such risks should not be ignored,

雖然這樣的風(fēng)險不容忽視,

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

但表親婚姻不一定會導(dǎo)致基因災(zāi)難。