Genetic engineering from A to Z Part 1
Remember, there ran a post stating gene technological lab “on the knee”. It turned out that the theme is interesting to the audience, so I decided to deal with its development with educational purposes.
I will give a clear and understandable way for ordinary people examples to describe complicated processes. If someone sees fit to correct me feel free. I will deliberately miss out on many things, but if you think that without them suffering the logic of presentation is also correct.
So, let's begin. Let's say we want to create transgenic a Christmas tree glowing in blue light. For example, British scientists recently discovered the gene blue glow. So look at this process in stages.
We will conduct an experiment like real scientists. They hear that a new gene, what to do next, if you want to create a tree?
A real scientist usually climbs in ncbi.nih.gov for several keyword searches for scientific publications on this topic. For example, “the blue glow gene shines". A typical situation when one of the links he really finds the article “British scientists”, which is an article by a group of Chinese authors, none of which responds to e mail.
On the other hand, in the article you can find out the name of the gene. Let it be called (gene names are usually given letter designations + index, and ahead can go the first few letters of the name of the organism from which it is allocated, they can be discarded). For example, can be decoded as blue light 1 gene. But the rules here are not strict.
The name of the gene in the database looking for nucleotide sequence of the gene. That's roughly sees the scientist on the screen.
By the way, we can use the BLAST tool, and inputting DNA sequences to which genes it can be treated. This is also a very important routine tool for genetic engineers.
So, we got the gene sequence. Very well, what's next? Because you need to get the gene. To do this, let us return to the question of what is DNA.
DNA is a long molecule (very long) is a polymer of four variants of small molecules, nitrogenous bases, simply “letters”.
Genome of the cell is divided into parts from one to several tens of DNA molecules, and usually each of them has his own copy of the twin carrying the same genes. Each of the DNA molecules in a special way folded to fit in the cell and coated with protein complexes to form a chromosome.
How do genetic engineers work with DNA if it is one and it is impossible to draw any direct manipulation? The fact that all the procedures are working not with one but with many DNA molecules, with thousands and millions of copies.
Thousands of identical molecules floating in water solution and this solution is called the “DNA preparation”. All manipulations with molecules are typical chemical methods.
That is, scientists are working not with one molecule and with a huge number of them in solution using chemical techniques.
How do we get the gene. There are two ways. The first is the direct chemical synthesis. However, they didn't get enough of long molecules due to errors of synthesis. I'll explain why.
DNA is a polymer. It is possible to synthesize building up brick by brick, and there are four bricks of different colors. At each stage of increasing the efficiency is about 99%. That is one hundred molecules one turns out wrong. Now imagine that we need to make a molecule with a length of 1000 letters? Then using trivial arithmetic, it appears that the true proportion of the molecules will be is 0.99^1000=0,00004
Grab her, then ventured into powder, then pour successively various compound filth towards the total bulk of tissue at the method exiting only the DNA molecule. The concluding outcome may be that the groundwork of DNA. The choice is produced of the comparatively large sample, so there's perhaps not a single DNA molecule and lots out of each mobile in some bits. This DNA comprises perhaps not merely the gene bl1, but most of one additional genes.