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从单细胞到多细胞生物或许没那么难 – 译学馆
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从单细胞到多细胞生物或许没那么难

The momentous transition to multicellular life may not have been so hard after all

Less than a billion years ago,
不到十亿年前
Life crossed a threshold.
生命有了新突破
Single cells started to band together,
单个细胞开始结合在一起
eventually evolving into the riot of shapes
最终进化了出像今天这样
and functions of multicellular life today.
形态不同功能各异的多细胞生物
It’s been thought that the evolution of multicellularity
过去人们认为向多细胞生物的进化
must have been a major genetic leap,
一定经历了巨大的基因飞跃
but new research suggests
但是新的研究表明
that it wasn’t such a difficult transition after all.
并没有这么大的转变
Scientists looked at an organism
科学家们研究了
that seems closest to making this leap.
似乎最接近这次基因飞跃的生物
Choanoflagellates while single-celled,
领鞭虫虽然是单细胞生物
resemble the specialized cells that line the channels of sponges,
却与形成海绵孔内层的特殊细胞相似
which are considered by many to be the most primitive living animal.
而海绵 很多人认为它是最原始的动物
A lab found 350 gene families in Choanoflagellates
某个研究室在领鞭虫基因中发现了
once thought to be exclusive to multicellular animals.
曾被认为是多细胞生物所特有的350个基因家族
The findings suggest that this single-celled organism
这些发现表明单细胞生物
is already equipped for multicellular life.
已经具备发展成多细胞生物的条件
A single cell’s life is simple but limited.
单个细胞的生命简单却有限
Like hermits,
就像一个隐士
microbes need only be concerned with feeding themselves.
微生物只需要养活自己
In contrast, cells in a multicellular organism,
然而 多细胞生物的细胞
give up their independence
则放弃了独立性
they take on specialized functions
它们承担起特殊的功能
they sacrifice their progeny for the greater good.
并为了群体的更大利益牺牲自己的后代
Take volvocaceae algae,
以团藻科为例
which comes in a spectrum of cellularity.
有一系列不同的细胞种类
A lab compared the biology and genetics of this diverse set of algae,
有实验室比较了不同藻类的生物特征和基因
and learned that as cells banded together,
发现当细胞聚集在一起时
existing genes took on new functions.
已有的基因展现出新的功能
Chlamydomonas is a single-celled alga
衣藻是一种单细胞藻类
that uses its centrioles for both swimming and reproduction.
它利用中心体游动和繁殖
So can’t do both at the same time.
所以两种活动不能同时进行
Its multicellular relative, Volvox, however,
然而 它的多细胞亲戚 团藻
can do both at once
却可以同时游动和繁殖
because its cells have specialized,
这是因为团藻细胞的分工
with some using the centrioles for swimming
有些细胞利用中心体游动
and others using it for reproduction.
有些细胞利用中心体繁殖
Yeast is a fungus consisting of a single cell.
酵母是单细胞真菌
One lab conducted a series of test tube experiments with yeast cultures
某实验室用酵母菌做了一组试管培养实验
to better understand
以更好地理解
how cells evolved increasing complexity.
细胞是怎样逐渐向复杂演化的
The biggest cells, which were the ones
那些最大的细胞
that settled to the bottom of the flask,
往往定植在试管底部
were allowed to survive and reproduce.
它们能存活并且繁殖
Within 2 months, daughter cells stuck to their mothers
过了不到两个月 子代依附着亲代细胞
and forms multicellular structures dubbed snowflakes because of their shape.
形成了“雪花”样的多细胞菌落
Over time they got bigger and more and more complex.
随着时间的推进 菌落逐渐变大且复杂
In this sped up simulation of evolution,
在这个被加速的进化模拟实验中
the yeast specialized cells.
酵母细胞出现了分工
In large snowflakes, certain cell undergo a type of suicide,
在大型菌落中 特定的细胞会执行自杀程序
releasing the cells at the tip to start a new snow flake.
释放顶端细胞 从而形成新的菌落
The dying cell sacrifices its life,
衰老的细胞牺牲自己
so that the group can reproduce–a hallmark of multicellularity.
以此换来群体的繁衍——多细胞生物的一大特点
The team conducted the same experiment
该团队又对衣藻
with Chlamydomonas and again,
重复了这个实验
a kind of multicellularity was quick to appear.
也很快得到了这类多细胞生物
Scientists are still debating
科学家们仍然在争论
what drove simple cells to become more and more complex,
是什么让简单的细胞变得逐渐复杂
but with these genetic comparisons and clever experiments,
但基因的比较和这些巧妙的实验告诉我们:
what was once thought as a major leap
曾经被认为的基因大跳跃
can now be seen as a series of small genetic steps
现在看来可能是一系列小的基因改变
that lead to the wondrous diversity of multicellular life today.
这些改变带来了如今奇妙多样的多细胞生物

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视频概述

新的研究表明,单细胞生物到多细胞生物或许并不存在很大的基因飞跃,而是一系列小小改变的结果。

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收集自网络

翻译译者

我爱数学

审核员

审核员LJ

视频来源

https://www.youtube.com/watch?v=hjTdbWblhxw

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