Do-it-yourself dna molecule model. DNA origami: how interesting nanometer-sized things are made from DNA
Do you want to make your own DNA model - basic structural element life? Then unleash your inner creator and create a DNA model out of polymer clay or beaded wire to create a model that is sure to take first place at any science fair.
Method 1 of 2: Making a Clay Model
- If you plan to exhibit your model at an exhibition, prepare a stand on which you can place it. It can be a small wooden board with a rod coming out of its center, to which the DNA strand will be attached.
- Once you've finished shaping your polymer clay, you'll need to bake it, so make sure you have a working oven as well.
- To provide additional support for the DNA model, you can use flexible wire in it.
Create two long strands to form a double helix. Choose polymer clay in one of your chosen colors and roll it into two pieces 30 centimeters long and one and a half centimeters thick. They will form the side strands of DNA, so it is necessary to ensure their strength so that other parts can be securely attached to the strands.
- To add extra stability to the model, you can wrap the clay around two long pieces of flexible wire.
- You are free to change the strand size of your DNA model to suit all your requirements. To create a shorter model, simply reduce the size of the double helix strands.
Add sugar and phosphate groups. The DNA double helix strands are made up of two types of groups: sugars and phosphates. Use one of your colored polymer clays to form the phosphate groups on the double helix.
- Roll out the clay of your chosen color for the phosphate groups until it is flat. Cut strips of clay one and a half centimeters long and wide.
- Starting at the bottom of the long strips of the double helix, wrap pieces of flat phosphate clay around the strand.
- Make sure they are well pressed into the thread of the spiral and will not fall off.
- Pass between the pieces of phosphate clay on a thread one and a half centimeters of empty space. The empty space in the strands of the double helix represents groups of sugars.
- Continue alternating the clay of sugars and phosphates one and a half centimeters apart until you have completed both strands of the double helix.
These are the four nitrogenous bases that make up the DNA strand: cytosine, guanine, adenine, and thymine. They form the rungs of the "ladder" between the two strands of the double helix. Choose one color of polymer clay for each of the four bases.
- Roll the clay of each color into pieces one and a half centimeters long and half a centimeter wide. Use a knife to cut off the edges and smoothen the surface.
- Count the number of sugar groups you created on the strand of the double helix. This is the number of base pairs you will need to make.
- Divide your colors in pairs into appropriate groups. Cytosine and guanine should always be together (in any order), as well as thymine and adenine.
- If you want to give your nitrogenous bases more stability, cut pieces of flexible wire about two and a half centimeters long and use them as the centerpieces of clay bases.
- Combine pairs of flowers by pinching the edges of your one and a half centimeter pieces. Once the colored pieces are joined in the middle, gently roll them into one smooth, solid piece of clay.
Attach the nitrogenous bases to the double helix. Once you have made all the 2.5 cm lengths of nitrogenous bases, you will need to attach them to the double helix.
- Start with the first group on the double helix. Use small, pea-sized pieces of clay that are the same color as the sugar group.
- Attach one of the nitrogenous bases to the sugar using a small piece of clay. Pinch the pieces of clay and smooth the edges by rolling them with your fingers.
- It will be easiest to attach all the pieces of nitrogenous bases on one side of only one of the strands of the double helix. Then, when all 2.5 cm bases come out of one strand of the double helix, attach the second strand to the opposite side.
- Make sure all parts are securely fastened. If you have threaded your nitrogenous bases into a wire, you can stick the ends of the wire into the strands of the double helix to better secure them.
Bend the double helix. To give your DNA model the classic helical shape, hold both ends of your double helix and turn them counterclockwise.
Bake your model. Follow the instructions on the polymer clay package and then bake your model to harden it.
- If you have wax paper, bake the model on it so that the model does not stick to the baking sheet.
- Always let the model cool down before pulling it out, otherwise you may burn yourself.
Once the model is baked and cooled, show off the fruits of your labor! Hang it from the ceiling with a fishing line, or attach it to a wooden stand.
Purchase materials and tools. To make a clay model of DNA, you first need to buy any clay you like. You can make a model if you have at least six colors of polymer clay, as well as tools with which you will mold the clay (for example, a plastic knife or a rolling pin).
Method 2 of 2: Making a Model with Wire and Beads
Gather materials. For this project, you will need several meters of flexible wire, wire cutters, and beads of your choice.
- If you want to increase the quality level of your model, you can use a soldering iron to firmly attach the parts to each other.
- You can use any beads, but glass beads will give the model a more beautiful look. If you like, you can add beads as a spacer between the larger beads.
- To match the desired size of the model, you will need beads in sufficient quantities of at least six colors.
- If you are going to put your model on display, then make a stand out of wood that you can attach your model to.
Make a double helix. It consists of two long side strands that hold the entire DNA molecule and give it the shape of a ladder. Cut two pieces of wire equal length. These pieces will serve as the backbone of the DNA model, so choose their length depending on the length of the entire model.
- Choose beads of two colors and attach one to each end of the wire. Pass the wire through the bead a second time, creating a loop at the end of the wire. This will prevent the beads from slipping off.
- Alternately attach beads of two colors to the wire. The two colors represent the sugar and phosphate groups that form the longest part of the double helix.
- You can thread one or many beads of each color, but make sure that you have the same number of beads of each color of the two on the wire.
- Do the same for the second piece of double helix wire, being careful to match the colors of the two beads (sugar and phosphate) on the two strands of wire next to each other.
- Leave 2.5 cm of unfilled space on top of the wire so you can attach the "ladder rungs" into the gaps between the beads.
Add "stair rungs". Count the number of sugar groups you made on the double helix, and then cut the 2.5 centimeter pieces of wire in the same amount.
- Wrap the ends of one piece of wire around the double helix of the sugar bead. Do this for all the pieces of wire so that you have a complete double helix strand with pieces of wire sticking out of it.
- If you want to make a more decorative and durable DNA model, use a soldering iron to solder pieces of wire to the strand of the double helix.
Make nitrogenous bases. Choose four other colors and assign a nitrogenous base to each. Guanine and cytosine are always paired, as are thymine and adenine.
- You will most likely need many beads to fill each small piece of wire, so when attaching beads to the wire, choose equal amounts of them for each nitrogenous base.
- Make sure you respect the grouping of pairs of beads. Always string cytosine and guanine together, as well as thymine and adenine. However, you can place them in any order and make some pairs more than others.
String your nitrogenous bases. Once you have separated all your beads, place them on the wire branches that come out of the double helix strand. Be sure to leave 1.5 centimeters at the end of the wire for attaching it to the other strand of the double helix.
Attach the second strand of the double helix. With all the nitrogen base beads added, prepare and attach the second strand of the double helix. Orient the side to reflect the first nitrogenous base and attach the pieces of wire.
- You can wrap the pieces of wire around the double helix using a pair of needle nose pliers. Attach these small pieces of wire in the same place you did for the opposite strand of the double helix.
- If you can, use a soldering iron to solder the last pieces of wire together, making the model look smoother.
Seal the ends of the pattern. To prevent the beads from falling out of the model, twist the wire at each end of the double helix strands into a loop. You can also solder the wire into knots to prevent the beads from falling apart.
Bend the double helix. To create the classic helical shape of a DNA strand, grab the ends and gently twist them counterclockwise.
Showcase your model. Once you've added all the finishing touches, your model is complete! Hang it from a hanger or ceiling, or attach it to a wooden stand with some wire or glue. Show everyone your work!
- If you are using an oven or a soldering iron to create your DNA model, be careful not to burn yourself.
- Both of these methods are too complicated for children, so if you are making a model for school project, make sure your helpers are old enough not to hurt themselves when handling the materials.
Many people probably know how easy and simple it is to replicate part of their own DNA. The process is essentially simple. But then how many enthusiastic lisps from the series “oh, how he / she looks like dad / mom!”. However, the task becomes much more complicated when you need to create some kind of abstract DNA model on your table from improvised materials.
What for it was necessary to me, ask? Very simple. My daughter at school has a subject similar to "biology" in Russian schools. Accordingly, the students were given a home project, which includes not only obtaining theoretical knowledge about the structure of DNA, but also creating a model of it. With this model, then you need to speak to the teacher and the class, telling what is in it and how.
In general, this will not be exactly “my” post. He is more dedicated to his daughter. Although I took some part in the process, basically this participation came down to consulting ... However, suddenly someone will be interested or, suddenly, someone at school will ask a child to do a similar thing. Here is the finished guide.
According to the conditions of the problem, the model must meet certain requirements. Interestingly, the student himself can choose what conditions he will fulfill. Each point of the presentation "weighs" a certain number of credit points. Accordingly, you can follow a simple path and score a certain minimum passing score or try to implement the “maximum program”.
Initial statement of the problem:
Just as it follows from the task, it does not have to be exactly the model. It can be anything - from a book with a story to a puzzle. The main thing is that it has some physical representation. Separately, it is noted that if the student decides to make a model, then it is forbidden to use a ready-made store set. Like this, for example.
The daughter decided to make a model and try to shoot the maximum number of points. OK.
We started with a computer model... I'm not really a real welder. Well, that is, in general terms, I know what DNA is, what it consists of and how it is usually depicted. No more. Therefore, from the very first steps, the daughter seized the initiative. She was able to explain to me what it consists of and what attaches to what.
It came out something like this:
When it became clear what parts we need, we went shopping. You will need: two sizes of foam balls, wooden rods, paint, glue and a piece of MDF for the stand.
Oh yes ... You will definitely need a Dog:
To be honest, I myself do not really understand what the hell the Dog is for, but he himself had enough confidence in this for all of us. In fact, he only interfered ... But maybe I just misunderstood something.
Styrofoam balls were bought at the "dollar" store. In the "everything for parties" section. I don't even want to try to understand how styrofoam balls can be used in the context of a party. But it's good that they were found. This was our most problematic moment. It was necessary to find such balls that would be easy to handle. For example, glass beads will not work - you'll get tired of drilling. Wooden ... In principle, they would fit. For me. But my daughter had to work, and I doubted that she would be able to evenly hole a wooden ball with a hand drill like that. Half constipated out of habit. And they are quite expensive. A softer and cheaper material was needed. The foam fit just perfect.
Wooden slats were bought at a building materials store. These rods are thinner cousins of the ones I used to decorate the bed and nightstands. There were no problems with this. They are always available in a wide variety in all hardware stores.
Paint/glue - trivial. We took the usual paint in an aerosol. At first they tried on one of the balls - the paint did not eat the foam. Accordingly, we bought the right amount of flowers. Glue - ordinary PVA.
I already had a piece of MDF-panel for the stand in the drawer. You can get to work.
Stand first. My daughter took my advice and printed out a template on the printer, which she glued onto a piece of MDF:
Her option was to find a saucer of suitable diameter and draw a circle on it. But I was able to convince her that such a path is not the path of a samurai. Who, if not me, knows that we do not have saucers of a suitable diameter with a smooth edge on the farm - everything with a wavy edge. We already swam - we know :-)
Surprisingly straight cut. I even freaked out a little...
She removed minor irregularities along the edge on a grinder:
To add aesthetics to the stand, its edge was machined on a cutter:
The result is a disk like this:
Well, the hole in the center into which the model will be inserted:
What followed was the tedious operation itself. It was necessary to take a foam ball and drill two through holes in it crosswise. Through the first hole, such a ball is mounted on a common axis, into the other hole, transverse sticks are stuck from both ends. It was necessary to make ten such balls:
It was the hardest for me. You have no idea what kind of torture it is to stand and watch. Instead of grabbing a dremel yourself and quickly drilling everything in a couple of minutes. The daughter managed it in about half an hour ... The unhurried methodicalness with which she did all this just killed me :-)
She called the result a shish kebab:
Now it was necessary to stuff transverse sticks into the barbecue. They were all cut from the same wooden bar as the central axis:
Again, she wanted to cut the sticks with a hacksaw, but I managed to convince her that a cutting disc and a dremel were much faster.
Next step: take the received sticks:
... and stuff them into the previously obtained kebab:
This was necessary in order to glue the central balls (by the way, this is not garbage for you, but real hydrogen bonds) with a common stick. In the photo you can see that another template is attached to the base on which the segments are marked. The crossbars are stuck into the ball, glue is applied to the central axis, the ball is set at the desired height and rotated along the desired marking sector. Those. on the this stage, the cross bars help position the center ball at the desired angle of rotation. Repeat ten times:
After that, the crossbars can be removed and the spare parts sent for painting:
Once everything was dry, we proceeded to the final assembly.
Deoxyribose was attached to each transverse rod ... It seems ... Deoxyribose in the original. The dog knows what it is... It doesn't matter. The main thing is that the daughter knows what it is. She should push the presentation in front of the teacher, not me :-)
These balls themselves should be white, so they did not have to be painted:
A long and painstaking process of assembling a model:
It remains to add only phosphate chains (phosphates). As far as we understand, it is customary to depict them in the form of the very recognizable double helix.
Two ribbons were cut out of thick thick silver paper:
These strips are glued to the tops of the extreme balls on the model. Like this:
At this stage, for the first time, I took a personal part. Two hands were not enough. It is necessary that one person holds and guides the strips, and the second one smears with glue and presses.
At the very least, we managed this procedure, eventually getting the desired model:
According to the conditions of the problem, it was also necessary to designate all the spare parts. We decided to limit ourselves to sticking the legend to the stand. Unfortunately, the color ink in the printer has run out. Therefore, I had to print a b/w version and color it with felt-tip pens:
Lamination didn't work the first time either. The unit chewed two labels before making the third normally:
I don't know what was the matter. I have already used this unit a hundred times and never before had he chewed anything ... One way or another, we received our label:
Model ready:
Now daughters need to memorize oral part presentations. But I can't help her with this. Hope it works out on its own. She has another week to study the theoretical part. I'll write later how I shot with the project ..
Choose a type of candy. To make side strands from sugar and phosphate groups, use hollow strips of black and red licorice. For the nitrogenous bases, take gummy bears in four different colors.
- Whatever candies you use, they should be soft enough to be pierced with a toothpick.
- If you have colored marshmallows on hand, they are a great alternative to gummy bears.
Prepare the rest of the materials. Take the rope and toothpicks that you use when creating the model. The rope will need to be cut into pieces about 30 centimeters long, but you can make them longer or shorter - depending on the length of the DNA model you choose.
- To create a double helix, use two pieces of rope of the same length.
- Make sure you have at least 10-12 toothpicks, although you may need a little more or less, again depending on the size of your model.
Cut up the licorice. You will hang the licorice, alternately changing its color, the length of the pieces should be 2.5 centimeters.
Sort the gummy bears into pairs. Cytosine and guanine (C and G), as well as thymine and adenine (T and A) are located in pairs in the DNA strand. Choose four different colors of gummy bears to represent different nitrogenous bases.
- It does not matter in what sequence the pair C-G or G-C is located, the main thing is that these bases should be in the pair.
- Do not pair with inappropriate colors. For example, you cannot combine T-G or A-C.
- The choice of colors can be completely arbitrary, it depends entirely on personal preferences.
Hang up the licorice. Take two pieces of string and tie each at the bottom to prevent the licorice from slipping off. Then string pieces of licorice in alternating colors onto the rope through the central voids.
- The two colors of licorice symbolize sugar and phosphate, which form the strands of the double helix.
- Choose one color to be the sugar, your gummy bears will attach to that color's licorice.
- Make sure the licorice pieces are in the same order on both strands. If you put them side by side, then the colors on both threads should match.
- Tie another knot at both ends of the rope right after you finish stringing the licorice.
Attach the gummy bears with toothpicks. Once you have paired all the bears, getting C-G groups and T-A, use a toothpick and attach one bear from each group to both ends of the toothpicks.
- Push the gummy bears onto the toothpick so that at least half a centimeter of the sharp part of the toothpick sticks out.
- You may end up with more of some pairs than others. The number of pairs in real DNA determines the differences and changes in the genes they form.
Carrying our genetic information) you can create all sorts of tricky, flat and three-dimensional nanometer-sized things. The same nano-technology as it is. In this review, I want to talk about the development of DNA origami: two-dimensional DNA emoticons, three-dimensional figures, DNA crystals with a programmed structure, DNA “boxes” with a lid that can carry molecules of the right substances and release them after a signal to open the lid, and and finally, dynamic structures such as a DNA walker walking along the substrate (the creators proudly say that this is already a nanorobot!). Who wants to learn more about why all this is needed, read about the technologies for making beautiful nanometer pieces from DNA, or just look at beautiful pictures, welcome under cat.
This is what a DNA nanorobot looks like
A bit of theory
At the end of the twentieth - beginning of the twenty-first century, the question arose of designing nanometer-sized objects. For what? The general vector for miniaturization has existed for a long time, and historically it has always been a “top-down” movement - for example, in the 70s, in the manufacture of microcircuits, the minimum controlled size was 2-8 microns, then this value rapidly decreased and now chips are in mass production , made on a 22-nm technological process. Here thinking people had a question: is it possible to move “from the bottom up”? Is it possible to force atoms and molecules to assemble into the necessary structures and then use these structures in technology? The requirements for such a “self-assembling” system are obvious: the materials for it must be sufficiently cheap and available, the self-assembly of the complex spatial structure of the system must be easily and obviously “programmed”, the system must be able to carry useful functionality. They immediately remembered that in nature such self-assembling systems already exist and work perfectly - these are macromolecules of all living organisms, for example, proteins. Here comes the first disappointment - proteins are too complex, their three-dimensional structure is set in a completely non-obvious way by many non-covalent interactions, and getting a protein with an arbitrary structure is still an absolutely non-trivial and unsolvable task. That is, it is technically impossible to use proteins to construct the necessary nano-sized objects. What to do? It turns out that there are other macromolecules whose structure is much simpler than that of proteins.In 1953, Watson and Crick published their model of the structure of DNA, which turned out to be absolutely correct. DNA (deoxyribonucleic acid) is an interesting linear polymer. One strand of DNA consists of a monotonically repeating sugar-phosphate backbone (it is asymmetric and has a direction, there are 5 "and 3" end of the chain), however, one of four nucleotides is attached to each sugar (deoxyribose in the case of DNA) (the synonym for the word nucleotide is “base "") - adenine, or thymine, or cytosine, or guanine. Usually they are denoted by one letter - A, T, C, G. Thus, there are only 4 types of monomers in DNA, as opposed to 20 amino acids in protein, which makes the structure of DNA much simpler. Then it gets even more fun - there is the so-called "Watson-Crick base pairing": adenine can specifically bind to thymine, and guanine to cytosine, forming A-T and G-C pairs (and more T-A and C-G, of course), other interactions between nucleotides in the simplified case can be considered impossible (they are possible as an exception under some rare conditions, but this is not important for us). Watson-Crick base pairing is also called complementarity.
Two DNA strands, the base sequence of which is complementary, immediately “stick together” into a double helix. The question arises: what if there are two complementary regions on one DNA strand? Answer: the DNA strand can bend and the complementary regions can form a double helix, and together with the bend, this structure will be called a “hairpin” (DNA hairpin):
What is the basis for the “sticking” of two complementary DNA strands (or, similarly, two complementary sections of one strand)? This interaction is based on hydrogen bonds. The A-T pair is connected by two hydrogen bonds, the G-C pair by three, so this pair is more energetically stable. The following should be understood about hydrogen bonds: the energy of one hydrogen bond (5 kcal/mol) is not much greater than the energy of thermal motion, which means that one single hydrogen bond can be destroyed with a high probability by thermal motion. However, the more hydrogen bonds, the more stable the system becomes. This means that short sections of complementary DNA bases cannot form a stable double helix, it will easily “melt”, however, longer complementary sections can already form stable structures. The stability of the double-stranded structure is expressed by one parameter - the melting temperature (Tm, melting temperature). By definition, the melting point is the temperature at which, in equilibrium, 50% of DNA molecules of a given length and sequence of nucleotides are in a double-stranded state, and the other 50% are in a molten single-stranded state. Obviously, the melting temperature directly depends on the length of the complementary region (the longer, the higher the melting temperature) and on the nucleotide composition (since there are three hydrogen bonds in the G-C pair, and couple A-T two, the more steam G-C, the higher the melting point). The melting temperature for a given DNA sequence is easily calculated from an empirically derived formula.
From theory to practice
So, we have studied the theory. What can we do in practice? With the help of chemical synthesis, we can directly synthesize DNA chains up to 120 nucleotides in length (just then the yield of the product drops sharply). If we need a longer chain, then it can be easily assembled from those same chemically synthesized fragments up to 120 nucleotides long (for example, Uncle Craig Venter distinguished himself by collecting DNA from pieces as long as 1.08 million base pairs). That is, in the 21st century, we can easily and cheaply make DNA of any sequence that we want. What we want is for the DNA to then fold into all sorts of tricky and complex structures that we can then use. To do this, we have the principle of complementarity - as soon as complementary zones appear in the DNA sequence, they stick together and form a double-stranded region. Obviously, we want to make structures that are stable at room temperature, so we want to calculate the melting temperature for these regions and make it large enough. At the same time, on the same DNA strand, we can make many different regions with different sequences and only complementary ones will stick together. Since there can be several complementary regions, as a result, the molecule can curl up in a rather complicated way! Something like this, for example:2D DNA structures
A methodological breakthrough was made by Paul Rothemund (California Technological Institute) in 2006, it was he who coined the term "DNA-origami". In his article in Nature, he presented many funny two-dimensional objects made from DNA. The principle proposed by him is quite simple: take a long (about 7000 nucleotides) "reference" single-stranded DNA molecule and then, using hundreds of short DNA clips that form double-stranded regions with the reference molecule, bend the reference DNA into the two-dimensional structure we need. Here is a picture from the original article, representing all stages of development. First, (a) draw the shape we need in red and figure out how to fill it with DNA (think of it as pipes at this stage). Next (b) imagine how to draw one long reference molecule in the shape we need (shown by the black line). In the third step (c), let's think about where we want to place the "staples" that stabilize the laying of the long support chain. Fourth stage (d): more details, we figure out how all the DNA structure we need will look like and, finally, (e) we have a diagram of the structure we need, we can order the DNA of the desired sequence!How can we assemble the structure we need from chemically synthesized DNA? This is where the melting process comes in. We take a test tube with an aqueous solution, throw all the DNA fragments into it and heat it to 94-98C, a temperature that is guaranteed to melt all the DNA (convert it to a single-stranded form). Next, we simply very slowly (over many hours, in some works - over several days) cool the test tube to room temperature (this procedure is called "annealing", annealing). With this slow cooling, when the temperature is low enough, the double-strand structures we need are gradually formed. In the original work, in each experiment, approximately 70% of the molecules were successfully assembled into the desired structure, the rest had defects.
Further, after the structure is calculated, it would be nice to prove that it is assembled exactly as we need it. For this, atomic force microscopy is most often used, which just perfectly shows the general shape of molecules, but sometimes cryo-EM (electron microscopy) is also used. The author made a lot of funny shapes from DNA, the pictures show the calculated structures and the result of the experimental determination of the structures using atomic force microscopy. Enjoy!
3D DNA structures
Once you've dealt with the construction of complex flat objects, why not move on to the third dimension? Here, the pioneers were a group of guys from the Scripps Institute in La Jolla, California, who in 2004 figured out how to make a nano-octahedron from DNA. Although this work was done 2 years earlier than the flat DNA origami, at that time only special case(obtaining an octahedron from DNA), and in the work on DNA origami, it was proposed common decision, therefore, it is the 2006 work on DNA origami that is considered fundamental.The octahedron was made from a single-stranded DNA molecule approximately 1700 nucleotides long, with complementary regions and also held together by five 40-nucleotide DNA adapters, resulting in an octahedron with a diameter of 22 nanometers.
In the figure, note the color coding on the 2D octahedron. See the areas marked with the same color? They contain both complementary zones (parallel sections connected by cross-links) and non-complementary ones (they are shown in the diagram as bubbles), while zones of the same color located in different parts two-dimensional sweep, interact with each other, forming a complex structure, shown in Figure 1c and forming a face of a three-dimensional tetrahedron. Enjoy beautiful pictures!
In 2009, scientists from Boston and Harvard University published the principles for building a three-dimensional DNA origami, as they say, in the likeness of a honeycomb. One of the achievements of this work is that people have written for the construction of three-dimensional structures of DNA (it works on Autodesk Maya). With this program, even a non-specialist can assemble the desired structure from ready-made blocks using a simple graphical interface, and the program will calculate the required DNA sequence (or sequences) to fold into this structure.
PPS: in a personal asked why DNA and not RNA. The answer is: I see two main reasons: (1) DNA is chemically more stable. All living organisms synthesize huge amount RNases, enzymes that destroy RNA. If you accidentally stick your bare finger into a test tube with RNA, there will be nothing left of the RNA - everything will be devoured by RNases. Therefore, they work with RNA in special rooms, etc. - there is much more trouble than when working with DNA. There are no such problems with DNA, put your finger into a test tube - there will be no DNA. (2) The cost of chemical synthesis of RNA is several times higher than the cost of DNA synthesis. I think that's why people have fun with DNA - cheaper and easier.
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