2021年经济学人 水产养殖--鱼食界的哥斯拉(2)

Rotifers are famously asexual. The last time members of one group of the animals, the bdelloids, had sex is reckoned by zoologists¹ to have been about 80m years ago. Members of Brachionus plicatilis are not as sex-starved as that, but they still reproduce for the most part by parthenogenesis. Indeed, the variety Dr Abe chose to work with, known as the Notojima strain, is, like the bdelloids, an obligate parthenogen. For this sort of mutagenic work, however, parthenogenesis is an advantage. It means that a successful mutated line of rotifers will not be diluted² by the genetic³ mixing caused by sexual congress.

轮虫的无性繁殖是出了名的。据动物学家估计，蛭形类动物的最后一次交配发生在大约8000万年前。褶皱臂尾虫的成员并没有那么地“性饥渴”，但它们仍多半通过单性生殖进行繁殖。事实上，安博士选择研究的品种(被称为能登品种)就像蛭形虫一样是专性单性生殖。然而，对于这种突变工作来说，单性生殖是一种优势。这意味着一个成功的轮虫突变系不会被有性繁殖引起的基因混合所稀释。

The Notojima strain is the largest L rotifer used by Japanese fish farmers. In her quest to make it larger still, Dr Abe exposed batches⁴ of the animals to ion beams of various strengths and compositions, and then put the survivors⁵ through three rounds of proliferation and selection of the largest of their offspring, to try to come up with the Godzillas of the rotifer world.

日本养鱼户使用的最大的L轮虫品种是三岛品种。为了使其更大，阿部博士将几批轮虫暴露在不同强度和组成的离子束当中，然后让存活下来的轮虫进行三轮繁殖并选择其中最大的后代，造出“轮虫界的哥斯拉”。

The upshot, out of more than 3,000 mutant strains that were larger than normal, was three promising⁶ lines which, at 350-370 microns long, nicely plug the size gap, and which are also more fecund⁷ than their ancestors. Both of these characteristics make the new strains ideal for use as fish food, and three subsequent years of study have shown them to be stable. Godzilla may be fictional⁸. But the idea that radiation, used carefully, can create animals that are giants of their kind, is not.

结果，在超过3000个比正常突变品种大的突变品种中产生了3个有希望的突变系，它们有350-370微米长，正好填补了大小差距，而且比它们的祖先更多产。这两种特性使新品种成为了理想的鱼食，并且随后三年的研究表明它们是稳定的。哥斯拉或许是虚构的，但“辐射(谨慎使用)能创造出同类中的巨型怪”这一观点名副其实。

1 zoologists   

动物学家( zoologist的名词复数 )

参考例句：

• Zoologists refer barnacles to Crustanceans. 动物学家把螺蛳归入甲壳类。
• It is now a source of growing interest for chemists and zoologists as well. 它现在也是化学家和动物学家愈感兴趣的一个所在。

2 diluted   

无力的，冲淡的

参考例句：

• The paint can be diluted with water to make a lighter shade. 这颜料可用水稀释以使色度淡一些。
• This pesticide is diluted with water and applied directly to the fields. 这种杀虫剂用水稀释后直接施用在田里。

3 genetic   

adj.遗传的，遗传学的

参考例句：

• It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
• Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。

4 batches   

一批( batch的名词复数 )； 一炉； （食物、药物等的）一批生产的量； 成批作业

参考例句：

• The prisoners were led out in batches and shot. 这些囚犯被分批带出去枪毙了。
• The stainless drum may be used to make larger batches. 不锈钢转数设备可用来加工批量大的料。

5 survivors   

幸存者，残存者，生还者( survivor的名词复数 )

参考例句：

• The survivors were adrift in a lifeboat for six days. 幸存者在救生艇上漂流了六天。
• survivors clinging to a raft 紧紧抓住救生筏的幸存者

6 promising   

adj.有希望的，有前途的

参考例句：

• The results of the experiments are very promising.实验的结果充满了希望。
• We're trying to bring along one or two promising young swimmers.我们正设法培养出一两名有前途的年轻游泳选手。

7 fecund   

adj.多产的，丰饶的，肥沃的

参考例句：

• The pampas are still among the most fecund lands in the world.南美大草原仍然是世界上最肥沃的土地之一。
• They have a fecund soil.他们有肥沃的土地。

8 fictional   

adj.小说的，虚构的

参考例句：

• The names of the shops are entirely fictional.那些商店的名字完全是虚构的。
• The two authors represent the opposite poles of fictional genius.这两位作者代表了天才小说家两个极端。