I do not know if it has happened, but whenever I know twins (and it may be identical, modeled as two drops of water) tell me that, in fact, do not look much. And worst of all is that true. They are not obvious differences and less for those who are not used to, but they are there.
Although should not happen, right? At the end of the day, if all the cells in your body have the same DNA, they should not be exactly the same? Not really. And the key to this mystery is how our genes “express”.
Story of two palaces
An old story goes that, at the whim of an emperor and a little egotistical desnortado, two architects had to build exactly the same palace in different parts of the Empire. Plans therefore be the same. But they could not speak or communicate in any way. Nor could they look at the work of the other, or be guided by nothing but their good work and indications of the monarch.
When they finished both works, the emperor asked the court painter he go and do two paintings with the idea of showing everyone he could that his empire was so powerful that it was able to create exactly the same in completely different places. That would be his label.
A couple of months later, the painter appeared with two huge pictures showing two different buildings. And, of course, the Emperor was furious. How was that possible? The same plans, the same stylistic instructions, the same initial sketches, but although it seemed, were not the same palace.
The way to solve it was exemplary. Or, at least, everything modélica can be expected from a medieval despot: the Emperor killed with his own hands, the dismembered pieces and sent these to all corners of the empire.
The old story ends with a moral: the two palaces could not equal. Available materials, the chosen land, climate requirements and whatnot, chance, did, do and make it impossible for both buildings are equal.
The planes of life
Relatively speaking, the DNA are those planes. Every cell in our body has, but except for a handful of genes that are expressed in all cells, each has a specific and only ‘run’ the parts of DNA that are necessary for that function function. Cell differentiation is basically to ‘tell’ to each cell which piece of DNA must read, transcribe and express.
And the cells do what they can. Believe me, it is not easy to be a cell. Depending on nutrition, health, physiological needs and many cells take “own” decisions, such as architects. There will be a few more fat than other twins, there will be a little more hair and a better physique.
Thus: the interaction with the environment (from feeding neonatal exposure to chemicals) make us different beings. Not much, it is also true, because the cells are terribly good. But enough.
A manner of speaking, a way to express
Earlier this year, a group of Japanese scientists discovered that a long stay in space changes the expression of our genes.After analyzing follicles of a number of astronauts, they concluded up to four genes linked to alopecia increased their effect during stays in microgravity environments.
The case of the astronauts is curious and gives a hint of what relatively easy it is to change the expression of our genes.But, and this is one of my favorite parts, even if we were able to get two twins live in exactly the same environment and have exactly the same stimuli, they would not be equal.
The stochastic noise, random, also play a role in the whole process. In short, what we are is a lengthy conversation among our ancestors, the world around us and chance. That’s what makes us unique, but others can not appreciate it.
