What is Epigenetics ?
Epigenetics is the field within the genetics studies that the influence of the reversible heritable changes in gene function that occur without changes in the sequence (the sequence of base pairs) of the DNA into the cell nucleus. It also studies the processes that affect the unfolding development of an organism. In both cases, is studied how gene-regulatory information that is not expressed in DNA-sequences still from one generation (cells or organisms) is transferred to the other - that is to say, (based on the Greek prefix), "in addition to," or 'supplementary to "the genetic information encoded in the DNA.
This type of regulation may focus on the DNA, the RNA or proteins and the works on the level of the cell nucleus or the cytoplasm. Nucleosomes play an important role.
Use within science
The term is used for a number of new areas of research in biology that are closely linked to genetics. The Greek prefix "επι (epi) is often translated into the Dutch language as on or near. (If in epicenter, epiphyte etc.)
The current use of the term epigenetics in biology refers to two areas:
-The investigation of the effects of genes on the phenotype in the development of an organism.
-The investigation of heritable changes in gene function without changing the molecular structure of DNA. This is also referred to the investigation of the influence of the environment on the phenotypic expression of genes.
DNA-methylation is one of the ways in which genes are "off" can switch and transcription can be blocked. DNA-methylation often takes place on CpG islands.
The epi mechanism: genomic stamping
Apart from the more or less ingrained gene sequence, which forms the basic structure in the cell in order to determine the genetic stock properties and their relative upper hand, there is a mechanism that this graft, called genomic stamping or genomic imprinting. Epimechanisme This has to do with the ability of the DNA to turn on or off a gene. Obviously, the further development of a new born organism undergoes the restrictions or provisions which are passed by the presence or uitpatroon. Taking into account the fact that there are 25,000 genes in the human genome, this provides a huge amount of possible profiles.
Relation to the environment in space and time
Research has shown that a hypothesis that was proposed by the British professor Marcus Pembrey, as environmental conditions would have an influence on the transferability is indeed confirmed. This research was done on the basis of a Swedish study together with Professor Lars Olov Bygren who had pointed this out to him. Data and figures from a wide and complete Swedish population could be shown that periods of relative famine in a first generation systematically significant manifestation of diabetes in the third generation resulted.
Stress results are hereditary
It is also shown that stress sensitivity in children whose mothers during pregnancy to strong stress stimuli was also exposed is proportionately much higher. Posttraumatic stress disorder (PTSD) in the third trimester of pregnancy cycle this transfer is greatest. Elevated cortisol levels as indicators of stress will be also observed in the baby.
Moreover, it appeared from the Swedish study that there was a difference in the sensitivity period in male or female grandparents. For the women is that at the time of the pregnancy of the mother, for future fathers is the sensitive period just before puberty.