Intervention on the genomes. Part 2

In the twentieth century, in the twenty’s it was realized that changes in the genome were increased by increasing the mutation rate and for some years and still is being done in some cases now, what people did is to have the seeds for example of a plant and a strong amount of radiation. Why that? To increase the amount of mutation and, by luck -as mutation is at random- by luck some of the characteristics then could be selected. But again, in this case as in the traditional domestication there is no direct change of specific parts of our genome. So, to which extent genomes “accept” or is normal for a genome to have these changes that we, humans, may introduce in them?

We have already seen in other chapters that genomes are fluid, are dynamic. Genome is not an entity that exists outside the living beings, that exists as a top of anything. All the genomes are changing, for example we saw in other chapters the amount of junk DNA we have in our genome. The idea is that the genome is fluid, is dynamic, it changes. It changes within a given individual, my genome changes day to day because my cells divide and in the division of the cells some mutations occurred, this is the reason why we age. Aging is a process of accumulation of mutations, of changing the DNA of my cells; or cancer in which the modifications are important for cells controlling self-division.

Along the generations is the same thing, we have mutations; we have changes along the generations that is the base of evolution. The idea then is that the genome has to be seen as something dynamic, a something that changes from one moment to the other, from one generation to the other and there are lots of changes that do occur. We cannot consider a theoretical, topic, perfect, reference genome. A reference genome may be any genome with any of the changes that may occur, and, in the genomes, there are point mutations, there are copy number variations, and there are transpositions; so mobile elements going from one place to the other in our genome.

So, there is a changing status continuously in the genome and we can see that just contemplating the composition of our own genome in which we are going to see that we have lots of elements that are elements that we think that they don’t have any special use for ourselves but that are pieces that jump from one place or the other, that are transposons. Pieces that they have a kind of autonomous life within the genome. The idea then is that in the genome we have lots of information which is not relevant for us but is relevant for making this dynamic of the genomes.

Just have a look at the amount of SINES and LINES (long interspersed nuclear elements or short) in which we can see that these elements exist in huge amount but change from one place to the other of the genome and also, we have in our genome lots of amount of DNA that happens to be the remaining of ancient viruses that attacked our ancestors.