Unless you are Adan, Eva or the clone of a certain person that you agree with this statement: We were all procreated by a woman and a man! Therefore, we are heirs of half of the DNA of each of our parents and we are carriers of maternal and paternal "brands" thanks to which we can live.
Imagine that two women wanted to procreate a daughter and using the appropriate genetic techniques they could create an embryo that had half the DNA of each one, do you think this embryo would develop normally? Are male and female DNA necessary in an individual?
Keep reading and discover the reason why men and women are necessary in the procreation process.
Our set of chromosomes
If you wanted to transport a thread of approximately 1 km scattered on a soccer field, obviously you would think of making one or more balls before moving it.In the same way it behaves nature with our DNA.When a cell in our body wants to divide and therefore needs to make a copy of its DNA, the latter is wrapped in “clews” or better called 'chromosomes', which allow the duplication of the genetic material is easier to make and in turn distribute the genetic material proportionally.
All the cells in our body have a total of 46 chromosomes in their nucleus (44 somatic and 2 sexual) except germ cells, such as sperm or ovu those, who only load half of chromosomes and end up completing “the chromosome game” that we all have in fertilization.
What is the imprint?
During fertilization it is formed a single nucleus by the union of the pronuclei of the sperm and ovule.It was before the union of the pronuclei that by means of a technique called “nuclear transfer” it was possible to change in the laboratory the masculine pronucleus for a feminine one obtaining a gynogenon (female genome only), and the female pronucleus by a male one resulting in a androgenon (male genome only); When monitoring these embryos, it was observed that both types developed erroneously and died .
However, the defects generated were different in each case and while an embryo developed one structure in a normal way the other did not get it and vice versa, so the male and female DNA was concluded are determinants in the normal development and viability of the embryos. It is perhaps because of this fact that the processes of cloning in mammals are inefficient, since the somatic nuclei used for nuclear transfer do not have the necessary imprint patterns for embryonic viability.
The phenomenon involved with the above fact was called 'Imprint', derived from the term "labeling", referring to the genes have an activation or deactivation mark of paternal origin; that is to say certain genes inherited by the individual are activated in the chromosome of the father and deactivated in the chromosome of the mother or vice versa , being this determinant in the development of the individuals.The imprint only affects 1% of the genes autosomal and this develops during gametogenesis, in testicles or ovules, through modifications in histones (proteins that accompany our DNA).The first step is the erasure of all inherited imprints and then make a new marking by which the genes will bear their corresponding paternal mark, for example the maternal imprints inherited by a male will be transmitted to their offspring as paternal and so on.
A clear example of the genomic imprint is as follows: The loss of a region of chromosome 15 can cause two types of syndromes, in the event that the affected chromosome is of paternal origin the individual will develop the Prader-Willi syndrome and if on the contrary it is of maternal origin the acquired syndrome will be that of Angelman .In other words, by means of the imprint our organism is able to discriminate between maternal and paternal DNA.
Image: thierry ehrmann, Ben Raynal
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