Incoming reprogramming events in zygote and primordial crime cells greatly affect epigenetic phenomena. When body cells are reprogrammed using Yamanaka factors inside the laboratory, there are very few changes in IPS cells. There are hardly any real ES cells. A group at Massachusetts General Boston and Harvard University surveyed any IEPS and ES cells geographically.They looked at genes whose expression differed between the two cells. The only major difference in expression was within a part of the chromosome called Dlk1-Dio3. Within some IPS cells, the expression of genes in this region was similar to that expressed in ES cells. These were the best IPS cells to make other body tissues.
Dlk1-Dio3 is an imprinted region in the chromosome number twelve of mice. It should come as no surprise that an imprinted region is so important. The Yamanaka technique initiated the process of reprogramming that usually takes place after the sperm and egg have been matched. During normal development, imprinted regions of the gene resist reprogramming. It is possible that even within Yamanaka’s synthetic method, they pose a major obstacle to reprogramming.
This region has long been the focus of interest of scientists. In humans, developmental problems and other symptoms appear due to uniparental dysmosis in this region. This region is also important for the prevention of parthenogenesis. Researchers in Korea and Japan have genetically manipulated this part of the mouse genome. They reconstructed the fertilized zygote with the help of two substances called pronuclei. One of them, the Dlk1-Dio3 region of the pronucleus, was transformed into a paternal imprint instead of a maternal imprint. The resulting mice were the first placental mammals with two maternal genomes
Reprogramming within primordial crime cells is not completely universal. It maintains more or less methylation over some IAP retrotransposons. The level of DNA methylation at AxinFu retrotransposon inside the sperm is similar to that of the body cells of mice of this strain. This suggests that methylation was not eliminated during the reprogramming of primordial crime cells, although modifications to other parts of the genome were eliminated. Resistance in both stages of epigenetic reprogramming of retrotransposons (in the zygote and in the primordial germ cells) provides a mechanism for cross-breeding hereditary transmission of the bent tail.
We know that not all hereditary transfusions occur in this way. In Agouti mice, the phenotype is transmitted through the mother instead of the father. In this case, during normal primordial crime cell reprogramming, IAP retrotransposons in each mother and father are removed with each DNA methylation. However, mothers who have DNA methylation pass on specific histone marks to their babies.
It is a represioblastic histone modification and it signals the DNA methylation machinery. This signal triggers the enzyme that inserts DNA methylation into specific parts of the chromosome. The result is the same. Maternal DNA methylation is restored in the baby. Male Agouti mice do not pass on DNA methylation or reperfusion histone modification to their retrotransposons. That is why the phenotype is always transmitted by the mother.
This is a slightly more indirect way of transmitting epigenetic information. Instead of direct transfer of DNA methylation, an intermediate reperfusion histone modification is chosen. That is why the transfer of phenotype from the maternal line is a bit confusing. Not all babies are like mothers-in-law because there is room for some discussion on how DNA methylation can be restored in children.
In the summer of 2010, reports of cloning of farm animals appeared in the British media. The meat of cloned beef has become part of the human food chain. Not the cow itself, but a calf traditionally bred from this cow. Although some alarming stories were published about it, its coverage in most mainstream media was balanced.
This was partly due to an ancient notion that led scientists to be very concerned about cloning. When cloned animals are bred, their offspring are healthier than they are. This is almost certainly due to primordial crime cell reprogramming. The first clones were created by transferring a somatic nucleus to a fertilized egg. This nucleus had only undergone the initial reprogramming phase, which usually occurs when the sperm and egg meet. ۔ Chances are, this epigenetic reprogramming wasn’t that impressive. Reprogramming an incorrect nucleus from an egg is a difficult and complex task. This could be due to the fact that clones are mostly unhealthy.
When clones reproduce, they pass on sperm or eggs. Before clones can produce these gametes, their primordial germ cells undergo a second stage of reprogramming. During this second stage, the epigenome is properly rearranged. Gametes eliminate abnormal epigenetic modifications of their cloned parents. Epigenetics explains why cloned animals face health problems. It also explains why this does not happen to their children. In fact, it is impossible to tell the difference between these babies and those born naturally.
Auxiliary reproductive technologies such as some technical aspects of the mating of male and female gametes in the laboratory are similar to cloning. In particular, the pleuropotent nucleus is transferred between the cells and placed in the laboratory before being transferred to the uterus. You find a lot of controversy in scientific journals about the rate of error caused by these methods. Some authors claim That the rate of imprinting diseases during pregnancy with the help of assisted reproductive technology is very high. This means that culturing the zygote outside the body disrupts the delicately formed pathways that control reprogramming, especially inside the imprinted parts. It is worth noting that there is still no consensus on whether this is really a medical issue.
Reprogramming of the entire genome has more than one effect during early development. It combines two very specific cells together to form a pluripotent cell. It balances the conflicting needs of the two genomes and ensures that this balancing work can be re-established in future generations. Reprogramming also prevents unnecessary epigenetic modifications from being passed from parents to children. This means that even though dangerous changes have taken place inside the cells, all of these changes will be eliminated before they can be passed on to the next generation.