A milestone in biology was reached this month when scientists in USA were able to create an entirely synthetic chromosome from a Saccharomyces cerevisiae, commonly known as yeast, in the lab.
To start this process they identified the full genetic sequence of yeast’s chromosome III, chosen because it’s one of the smallest chromosomes and can therefore be replicated more easily.
But it was still too big, so they took out a few less than 45,000 nucleotides, all of those thought to be ‘junk’ DNA, that is, DNA that doesn’t seem to have any function. This left 270,000, all of which had to be joined together to make up the chromosome, starting from scratch.
This is an enormous amount of work, so they ended up working with a team of 60 undergraduates, each team building a part of the chromosome until they were all joined together to form the final masterpiece.
Once the chromosome was ready, they inserted it into the yeast cell, and fortunately it seemed to work just as fine as the natural one would. They are now working on repeating this task on the whole of the yeast’s genome, instead of only one chromosome.
There have been some experiments in the past which managed to recreate the genome of organisms, especially bacteria, but no one up until now had managed to change it so much and still have it work. It is an outstanding feat in science that could teach biologists a lot more on how genes work and interact with each other.
However, this achievement is not only good in the way of creating artificial life, but it could also show some improvements in the chemical industry world.
When they decided which nucleotides to take out, they also haad to chose some changes to be made to the genome, so as to learn something from the genes changed. One of these tweaks was to change the stop codon, TAG, to TAA. This meant that TAG now doesn’t code for anything, but scientists could change this so it codes for a new amino acid, not found in the cell before. This could give rise to new substances and biopolymers, whose properties could prove to be very useful. If this worked, we could eventually have cells become factories, all with changed genetic sequences, so they produced new chemicals for many possible functions.