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When you look at a zebrafish, you probably just see a cute, tiny fish that's smaller than your pinky finger.
当你看一条斑马鱼时 看到的可能只是一条可爱的 比小拇指还袖珍的小鱼
But this little fish is so much more than that.
但这条小鱼远不止看起来那么简单
You're looking at an amazing scientific tool that has led to some major discoveries.
Zebrafish have been used since the 1970s to study the development of vertebrates, and more recently,
自20世纪70年代起 斑马鱼就被用于研究脊椎动物的进化历程 最近
they've been helping scientists learn more about human diseases and maybe even develop some potential treatments.
它们在帮助科学家进一步地了解人类疾病 甚至可能开发出一些具有潜力的疗法
So why the zebrafish? Well, like all fish, their genomes are similar to the human genome,
那么 科学家为什么选用斑马鱼呢？ 首先 像所有鱼类一样 斑马鱼的基因组与人类相似
mainly because we share a common ancestor.
这主要因为我们有 共同的祖先
They have over 26,000 protein-coding genes, and about 70% of those genes are related to similar genes in humans.
斑马鱼拥有超过26000个蛋白编码基因 其中大约70% 与人类基因相对应
Since zebrafish have been studied so much, we know that around 80% of the disease-causing genes
由于对斑马鱼的研究已经十分深入 我们了解到大约80%已确定的人体致病基因
that have been identified in humans have at least one related gene in zebrafish.
都至少有一个对应基因存在于斑马鱼体内
By studying what these genes do in zebrafish, scientists can learn more about what they do in humans.
通过研究这些基因在斑马鱼体内的作用 科学家能够更多地了解它们 在人体内的作用
And there are other reasons researchers specifically study zebrafish: They're cheap to maintain,
其他的原因也促使研究人员专门研究斑马鱼 饲养它们很便宜
and the females can spawn around 200 to 300 eggs in a single week, which makes for a lot of new test subjects.
且雌鱼在一周内可产下200至300枚卵 这提供了大量的新试验对象
More importantly, zebrafish embryos and larvae are transparent and develop really quickly.
更重要的是 斑马鱼的胚胎和幼体都呈透明状 并且生长迅速
There's even a genetically-engineered strain of zebrafish that's transparent through its whole life.
甚至有一种转基因的斑马鱼 终其一生都是透明的
That transparency allows researchers to see exactly what's going on inside the fish's body,
这种透明的特性让研究人员能确切地看见斑马鱼体内发生了什么
and watch biological processes — like how cancers develop.
并观察生物学过程——比如癌症是怎样形成的
That said, zebrafish still aren't the perfect model for human disease —
即便如此 斑马鱼仍然不是人类疾病的完美模型——
for one thing, they don't have lungs or mammary glands.
一方面 它们没有肺和乳腺
Plus, a lot of their genome is made up of duplicate genes.
另一方面 它们基因组的大部分是由多拷贝基因组成
Some of those gene copies might have mutated and developed functions that weren't there in the ancestor's gene —
其中一些基因拷贝可能已经突变 获得了祖先基因不具备的功能——
which would make them different from the human versions.
这使它们不同于人类的版本
Even so, zebrafish have been able to help scientists learn about a lot of different diseases --
尽管如此 斑马鱼已经能够帮助科学家了解许多不同的疾病——
like melanoma, the most dangerous type of skin cancer.
比如黑素瘤 最危险的皮肤癌类型
Cancer develops because of mutations in specific genes that affect how cells multiply and die.
特定基因的突变影响了细胞增殖与凋亡的方式 癌症因此而形成
And the most common mutation related to the melanoma is called BRAF(V600E).
最常见的黑素瘤相关突变叫做BRAF V600E基因突变
Zebrafish that carry this mutation, and also lack a tumor-suppressing gene, make good models for the disease.
携带这种突变基因 并且也缺少抑癌基因的斑马鱼成为 这种疾病的良好模型
So researchers can study how cancer develops in fish with the BRAF mutation, and use them to test treatments.
因此 研究者可以研究癌症怎样在BRAF基因突变的斑马鱼体内形成 并且用它们 来试验治疗方法
They've also used zebrafish to find other melanoma-causing genes.
他们也利用斑马鱼来发现其他导致黑素瘤的基因
See, sometimes, the BRAF mutation just causes benign moles instead of melanoma.
要知道 有时BRAF基因突变只会导致良性痣而非黑素瘤
BRAF might start the process, but another gene has to cooperate to actually cause the melanoma.
BRAF基因突变可能会启动这一过程 但另一种基因必须协同工作才能真正导致 黑素瘤
The question was how to find that gene.
问题是怎样才能找到那种基因
The researchers used human melanoma samples to look for duplicated genes that might cause
研究人员使用人类黑素瘤的样本 沿着一条染色体的特定部分寻找可能导致
cancer along a certain section of a human chromosome.
癌症的多拷贝基因
The duplicated genes they found were then inserted into the genomes of zebrafish with the BRAF mutation.
他们将找到的多拷贝基因插入到携带 BRAF基因突变的斑马鱼基因组中
And only one gene, called SETDB1, was found to accelerate melanoma formation in the zebrafish.
发现只有一种叫做SETDB1的基因 能加速斑马鱼体内黑素瘤的形成
This discovery might lead to the creation of new cancer therapies that target SETDB1.
这项发现可能推动产生以SETDB1基因为靶点的癌症新疗法
Zebrafish research might also be able to help with stem cell transplants.
对斑马鱼的研究也可能会有助于干细胞的移植
And the reason for that has to do with a compound called prostaglandin E2.
其原因与一种名为前列腺素E2的复合物有关
In a study, researchers discovered that when certain chemicals were used to enhance prostaglandin E2 synthesis,
在一项研究中 研究人员发现 当使用某些化学物质来增加 前列腺素E2的合成时
the amount of hematopoietic, or blood, stem cells in the zebrafish increased.
斑马鱼体内造血干细胞的数量上升
So, extra prostaglandin E2 might be able to help treat someone who's getting a blood stem cell transplant,
因此 额外的前列腺素E2可能会有助于治疗正在接受 造血干细胞移植的人
like a leukemia patient or someone with a blood or immune system disorder. Which is great news!
像白血病患者或是血液或免疫系统紊乱的人 这是个非常棒的消息！
This discovery eventually led to the creation of a drug called ProHema
这项发现最终导致了一种名为ProHema的药物的产生
that's supposed to improve the success of hematopoietic stem cell transplants using blood from umbilical cords.
预期它能提高用脐血进行造血干细胞移植的 成功率
Between 2014 and 2015, it went through stage II clinical trials where it was tested on patients to see how well it works.
2014年至2015年 ProHema经历了二期临床试验阶段 即在病人身上试验 以观察疗效如何
And the results are pretty promising. In patients who were taking ProHema,
测试结果令人倍感希望 干细胞移植在服用ProHema的病人体内
stem cell transplants seemed to start working earlier than the control group.
似乎要比在控制组更早开始 发挥作用
So, ProHema might help improve the effectiveness of these stem cell transplants, but it still needs to be tested more.
因此 ProHema可能有助于提升干细胞移植的疗效 但它仍需 接受更多的测试
A specific trait of zebrafish might also help scientists with regenerating human tissue.
斑马鱼的一个显著特点可能也会在人体组织再生方面帮到科学家
If a zebrafish heart gets damaged, it can regenerate.
如果斑马鱼的心脏受损 它能够再生
Even if part of the heart is removed, it'll just form a clot at the wound site,
即使部分心脏被移除 也只会在伤口处形成一个凝块
which eventually gets replaced with new cardiac muscle.
而凝块 最终会被新生的心肌取代
But if part of a human heart gets damaged -- like from a heart attack --
但如果人类心脏的一部分受损--比如由于心脏病--
the damaged area generally just turns into scar tissue, which doesn't pump as well as healthy tissue.
受损的 区域通常只会变成疤痕组织 而疤痕组织的泵血能力弱于健康组织
If you could regenerate healthy cardiac muscle instead, you could avoid that permanent damage.
如果能使健康的心肌再生 代替疤痕组织 就可以避免永久性的损伤
While it's still being studied, it seems like the reason zebrafish can do this and
虽然仍处于研究中 但似乎斑马鱼能这样而我们不能
we can't is because the injury activates their cardiac muscle cells, which then regrow the tissue.
是因为伤口使它们的心肌细胞活化 而后细胞重新生长 为组织
As scientists learn exactly how that's done,
随着科学家对该过程的具体研究
the idea of human tissue regeneration might get closer to becoming a reality.
人体组织再生的想法 距成为现实可能又近了一步
So the zebrafish may be tiny. But it's helping modern medicine in a big way.
所以 斑马鱼也许很小 但它正极大地帮助着现代医学
Thanks for watching this episode of SciShow, which was brought to you by our patrons on Patreon.
感谢观看这一期的科学秀 感谢Patreon上我们的用户带来 这一期的话题
If you want to help support this show, just go to patreon.com/scishow.
如果你想支持本节目 只需访问patreon.com/scishow
And don't forget to go to youtube.com/scishow and subscribe!
同时不要忘记去youtube.com/scishow订阅我们的节目哟！
