6-Letter DNA!

preview_player
Показать описание
Scientists have created living bacteria with two extra letters of genetic code, nicknamed X, and Y for short.

Animated by Kyle Norby

Life has been evolving on earth for about 3.7 billion years.
In spite of its diversity, all living things have one thing in common – DNA,
a fundamental code containing just four chemical letters; adenine, thymine, guanine, and cytosine. Until now.

Synthetic biologists from the Scripps Research Institute in California have, for the first time, created semi-synthetic E. coli bacteria with a 6-letter genetic code.

That might sound like something out of Jurassic Park, but even in Jurassic Park the cloned dinosaurs were coded using A, T, G and C.
These new semi-synthetic organisms are an entirely new variation on life.

The two synthetic bases that have been added are dNaM and dTPT3, but for short they’re called X and Y.

The team have been hunting for the right chemical candidates to add to DNA since the 1990s.
Any successful addition to the base pair family would need to match their ability to stick and unstick as the double strand of DNA zips and unzips, while fooling the cell’s own repair machinery into thinking it belongs there.
The team had come up with base pair candidates by 2008, but the next challenge was getting them out of the test tube and into a living organism.

In 2014, the geneticists managed to slip versions of X and Y into the circular plasmid ring of DNA in an E. coli bacterium.
While the E. coli managed to hold onto the new bases for a short period and even reproduce, it eventually rejected them.

Now the E. coli they’ve created aren’t just stable, they’re healthy and capable of growing.

Right now, these new types of E. coli can’t do much more than copy their unique string of genetic code. So what’s the point of adding more letters?

Well, it changes a lot. And to understand that, we need to go back to the earliest days of DNA discovery.
While history has made names such as James Watson, Francis Crick, and Rosalind Franklin synonymous with the discovery of the physical structure of DNA, the global search for such a chemical coding system was inspired by a name better known for his account of a dead-but-not-dead cat.

In 1944, the physicist Erwin Schrodinger, delivered a series on how ordinary matter can create complex living organisms. How could genetic information be stored?

His solution was something called an aperiodic crystal - a chemical with a repetitive structure, but with variations for encoding genetic information.
He felt such a material could easily fit inside a cell, and hold enough information to describe incredibly complex chemical machines.

The search was on to identify this aperiodic crystal and its variable pattern of interlocking chemicals.
Wrapped up in the dark insides of the cell’s nucleus, Deoxyribonucleic acid was the perfect candidate.
It took Watson and Crick using Franklin’s X-ray diffraction images to show how ideal its structure was for containing such a code.

So for the past half-century, we’ve understood how vast complexity can arise in living organisms using remarkably simple codes.
When the four letters of DNA are put together in short combinations of just three letters, those four chemicals can create 64 unique chemical words, or codons.

These link together in extensive sentences to produce a seemingly endless variety of genetic sequences, coding for a multitude of proteins and genetic programs.

Adding new bases seems like overkill when we can already do so much.
Yet the important thing about these new letters is their uniqueness.
Found nowhere else in nature, organisms coded with them offer scientists an unprecedented level of control.

The next step is getting these new bases to make changes to the organisms themselves.
New amino acids could be designed to be activated by the new genetic codes, amino acids which could be used to make new therapeutic drugs.

But should we be concerned about this new form of life?

Given the artificial nature of these new X and Y bases, even the hardiest synthetic specimens can’t survive outside the lab.
That’s because the organisms can’t produce X or Y on their own and there’s no supply of X and Y in nature.

The team has shown in multiple experiments that if X and Y aren’t provided, the semi-synthetic E. coli die every time,
so there is no risk of them getting out and spreading these new bases into the gene pool.

In fact, in many ways, this research is about enhancing the safety of biotechnology by providing more ways to control new organisms.

It’s not yet clear how far this work will or should be allowed to progress. It’s still very early days, but one day far in the future,
people might look back and think it was quaint there was a time when the only genetic letters scientists could work with were the ones nature provided for us.
Рекомендации по теме
Комментарии
Автор

"I'm making a 2nd channel to make more videos."
7 months later.

Phanth
Автор

If you guys think this is cool, you're gonna flip when you hear about the synthetic amino acids we've already incorporated into proteins. Now that we've got extra bases, maybe we can make new codons to finally code those synthetic amino acids into protein sequences. All we need now is new tRNAs, new tRNA loading enzymes for the new aa's, new biosynthesis pathways for those synthetic amino acids (that should only be 6-12 new genes we have to add to the organism), new biosynthesis pathways for the new nucleotides, proofreading enzymes for the new bases, polymerases that can handle the new bases without screwing up… sigh. Biology is hard. But awesome!

besmart
Автор

This guy is just pumping out videos like crazy! Grey could learn something.

theworldeatswithyou
Автор

Opens secondary channel to publish more quickly

6 month gap in videos

scarwolf
Автор

That was fascinating! As a biologist it's nice to see you make a video about biology. You should make more videos about the biological sciences.

asdef
Автор

It's been three months! Derek is defeating the entire purpose of this channel.

nishantbhaskar
Автор

Now send this ecoli on a virgin planet and let them evolve, develop consciousness and ask themselves how DNA came about and why there are 6 of them.. xD

TimmacTR
Автор

calling them x or y is a bad idea because they could be mistaken for chromosomes in papers

lalafellgaming
Автор

Why are you letting this channel die?? I like the greater depth! Please keep it going....

logancarpenter
Автор

last - on a related note, first i heard of DNA labels was from the movie GATTACA!

mmarsbarr
Автор

Wish this channel would keep uploading, i was loving it when it did.

mrailu
Автор

Isn't this one of the most significant achievements in human history? Why isn't anyone else talking about this?

futhamucka
Автор

Its still super impressive in my opinion that life came about only with a 4 letter code.

MrTote
Автор

I'm so down for kickstarting the next step in human evolution.

darugosuenyo
Автор

As a biology student, planning on specializing in molecular biology and genetics, this was incredibly fascinating to me. Thank you

Dr_Bille
Автор

In the telomere that lives inside us
And the people walking down below,
Crawling home alone like spiders
As the cancer slowly starts to grow...

- From " Curve of the Earth "album by the Indie Rock Band!

The-Anonymous.
Автор

I like these Sciencium videos, but why are there only 4 with a 7, 5 month gap now? I just tumbled upon this channel after watching Veritasium and I'd like to see more of both! Common, keep it up! :thumbsup:

markusk
Автор

I'm so glad, that you launched that channel. It's very pleasant to find this small videos regulary.

VyacheslavAzarov
Автор

Well, by adding 2 more bases the chances of having a random mutation during the replication of dna drastically increase, that might either lead to species capable of evolving extremely fast, or species that have too many malignous mutations in their dna that most of the individuals would die before being born

lorenzogiancristofaro
Автор

The pacing here was better than before, and it stayed interesting for that whole extra minute :)

animistchannel