aMoS [003] 缺失能量制造基因的槲寄生

槲寄生的基因出现退化？

因为听录音之前已经在标题中看到mistletoe这个词，所以感觉这篇还是比较能听懂的。于是趁中午休息时间做了下听写，感觉除了两处地方，大致还是听懂了。不过后来对照了文本，还是满篇飘红，光单词拼写错误及单复数不一致的地方就有不少，汗…… 不过，像线粒体（mitochondria）这种单词，拼不出来还是蛮正常的~~~

大致意思是说，槲寄生细胞内少了几种用于制造能量的基因，但可能因为是寄生植物，所以倒也存活了下来。

mistletoe: 槲寄生
cellular respiration: 细胞呼吸，生物体细胞把有机物氧化分解并产生能量的化学过程。无论是否自养，细胞内完成生命活动所需的能量，都是来自呼吸作用。真核细胞中，线粒体是与呼吸作用最有关联的胞器，呼吸作用的几个关键性步骤都在其中进行。
compartment: （细胞）区室
mito'chondria: 线粒体，单数为 mito'chondrion，形容词为 mito'chondrial
molecule: 分子
parasite: 寄生生物，形容词为 para'sitic

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音频下载及链接：

3种语速的音频文件已上传百度云：链接| 密码: ez6k（在百度云点击MP3文件名可直接在线听）（原始语速来自A Moment of Science官网，1.5倍及2.0倍语速版本为我个人后期调整的）

本期文章原始音频、配图及文本均来自A Moment of Science官网：链接

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文本：

（参照源网页的文字、根据实际录音内容修改而成）：

Don: Yaya, I just found out something about mistletoe.

Yaya: It's poisonous, Don?

Don: Nope.

Yaya: Kissing under the mistletoe in ancient Rome's tradition?

Don: Nope.

Yaya: OK, I give up.

Don: Scientists at Indiana University found that one species of mistletoe lacks several genes involved in energy production in cells. This is the first plant or animal discovered with this sort of condition.

Yaya: Are you talking about cellular respiration?

Don: Yes. Cellular respiration occurs in cells, special compartments called mitochondria. Their chemical machinery takes sugar and oxygen and produces energy molecules. Some of the genes that run this machinery are located in the mitochondria. The mistletoe species the scientists examined has lost all nine mitochondrial genes encoding one part of the energy production.

Yaya: How can it survive without all the normal genes?

Don: Scientists think this mistletoe species has gone through a strange “de-evolution.” This may be because mistletoes are parasites which need host plants to complete their life cycle. This particular species attaches to the stem of its host plant and steals nutrients for survival.

Yaya: So, if it’s stealing nutrients, it might not need the genes to make its own energy.

Don: The plant still needs to generate energy from the nutrients it steals and the scientists don’t know how the plant compensates for the lost genes. Since there are over 2,000 mistletoe species, the scientists want to check other species to see if this condition is an exception. Maybe all parasitic species lack that set of genes. Whatever they discover, this is all new and surprising information that will help scientists understand the evolution and function of parasitism in plants.

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附：听写记录：

飘红的听写记录