Chimerism in Humans

chimaera according to the genome glossary is an organism which possesses jail cells or tissues with a diametrical genotype. This can be caused due to mutated cells of the host organism or cells from a disparate organism or species.According to Greek mythology, the original Chimera (pronounced as kih-MEE-ra, and the adjective form chimerical pronounced as kih-MER-ih-cal) was a fire-breathing female monster with the head of a lion, the automobile trunk of a cig bet and the hindquarters of a dragon. The terrifying Chimera may have further been a product of a substandard family environment her father was the ogre Typhon, her find the half-serpent Echidna. Her siblings were the Cerebrus (the three-headed hound who eventually run aground work guarding the gates of Hell), snake in the grass (a nine-headed aquatic monster) and Orthrus (the runt of the litter, a prosaic 2-headed dog). As per the mythology, Chimera pounced round making e reallyone wretched until one day a man name d Bellerophon, locomote on the winged horse Pegasus slays her. Author un have sexn, Chimera, 2004Though believed to be a fab epic, it was found that cases of Chimera were actually prevalent in humans when accepted intriguing distressing cases erupted. One such case was when a char has been raped by a man and the women claimed a particular more than or less(a) clay to be the culprit. However, the crime judge authorities had found it difficult to inpatient the suspect. It so happened that the desoxyribonucleic acid interpreted from his crosscurrent sample did not tick the DNA of the suspect. However, extensive investigation and the victims statements revealed it to be comparable soul being responsible for the crime. When another series of DNA tests were taken from the suspect, this time from his hair sample it was found that the DNA sample perfectly matched. This revealed a breath fetching phenomenon among human genome which has resulted in various problems in the crimi nal justice system.Those people who have ii types of DNA in their body argon called chimaeras after the mythological creature with a head of lion, body of a goat and a tail of a serpent. These people ar sometimes as well referred to as mosaics. It has found that these people have devil different types of DNA in various parts of their body. Though a rare go onrence, this could have been due to various reasons. Vladar, 2004One of the common reasons is that chimeras are create if developing fraternal twin embryos join to depressher to stupefy one embryo. This is something which is completely opposite of identical twins who are create when a champion embryo splits into two. This occurrence takes coiffe in the very(prenominal) early stages of the embryo development i.e. when it is still in the form of unspecialized cells, so when it develops the baby that is born is healthy but with two types of DNAs. It is also found that fraternal twins dont have resembling set of DNA, ho wever, they the two fraternal twin embryos fuse together it results in chimera.Another reason for chimeras to form is when developing fraternal twin partake the same rail line supply. This usually happens when the twins with different DNA partake in a placenta in the mothers womb and cells from their blood mess up together. This results in the twins being chimeras based on scarcely their blood as other cells are not affected by the blood supply. Chimeras are also formed through some mistakes or mutations taking place in the division of the cells in the development embryo. This mainly takes place when the cells split into two so that they are able to be formed into more of themselves for the growth of the embryo. It also results in the the doubling up of the DNA by the cells which gets divided between the two new halves. During this process, if something goes wrong, therefore some new cells result in having different DNA. If this happens in the early stages of the development, then the tissues which are developed from the cells will have different genotype.It is difficult to label the exact number of chimeras in the world. We are able to find come proscribed of the closet whether a person is a chimera or not only when his / her DNA is analysed. This causes varied problems with regards to solving of crime cases and also results in crookedness with regards to donation of organs. In recent years, exciting results have been found out that a section of genetically incompatible cells may contribute to conditions equivalent asepsis, autism and Alzheimers disease. Migliore, L et al, 1999Human chimeraism came into being with advent of blood typing and it was found that some people had more than two types of blood group. Most of the cases of chimeraism are the blood chimeraism i.e. non-identical twins sharing a blood supply in the womb. Twin embryos often share a blood supply in the placenta, allowing blood stem cells to pass from one embryo and settle in the bone marrow of the other, seeding a lasting source of blood. As a result, almost 8% of non-identical twin pairs have chimeric blood. van Dijk, B A Boomsma, D I and de Man, A J M, 1996Apart from those who have chimera due to different blood types, there are even larger numbers of people who have this phenomenon due to carrying smaller numbers of different blood cells that may have passed through the mother and the fetus crossways the placenta or persist from a blood transfusion. It has also been analysed that the presence of some foreign white blood cells might be the cause for autoimmune diseases wherein the immune system affects the bodys own tissues. Nelson, J L, 2002 align chimeras are usually identified when they possess male and female cells resulting in the formation of hermaphroditics or any related problem in the persons sexual organs and their chromosomal sex is identified by their blood test. So the real number of chimeras and mosaics are much more than those that have been identified till date. Unless and until a chimera comes forward to get his blood sampled or has been convicted for a crime, it wouldnt be possible to know whether he actually is a chimera. This has resulted in further complication in solving some crime justice cases.It has been also crumbled that with the adjoin in in-vitro fecundation (IVF), there has an increase in the cases of chimeras. To avoid infertility among women, IVF has been quite common in the present day scenario. In this process, two or more embryos are placed in a womans uterus so there is an increased success rate. This results in 25% more cases of twin pregnancies than expected. With the increased number of twins, there is likelihood of more cases of chimeras. This was proved by Bonthron who found out that the British hermaphrodite boy who was a chimera was formed by IVF. Strain, L Dean, J C S Hamilton, M P R and Bonthron, D T 1998According to various tests undertaken along with ultrasound examinations per formed on the mother who was carrying the single fetus, the baby that was born had a normal right testis and a semi-developed left testis. An operation was conducted when the child was 15 months old and the surgeons removed an antidromic gonad and vas deferens. Pathology studies later exposed that these were actually an ovary with a fallopian resistance attached.Studies revealed that the childs chromosomes had both female (XX) and male (XY) cell lines. This was explained to be that the child was an extraordinary case of a true chimera which was a mixture of two embryos from separately fertilized eggs. The other likelihood was that two different sperm had outstandingly developed into a single mature egg before cell division had taken place. To distinguish between these possibilities, the researchers psychoanalysed DNA beloved the centromeres of the childs chromosomes, which are involved in cell division. Author unknown, DNA puzzle of mother made of two women, 2004Apart from thi s, the study conducted also revealed that chimerism can occur naturally, resulting in children with vague genitalia, however published data on the phenomenon is very restricted and many XX/XY children may go unnoticed. Even so, the event that chimerism occurred in a child born following in vitro fertilization should be taken seriously. Author unknown, 2004 In Vitro Fertilization Results In Chimera, 2004Considering these above points, it is sightly more and more difficult for the crime justice system to analyze the crime due to the increase in the cases of chimeraism and mosaicism which in turn is change magnitude with the increase in in-vitro fertilization. The criminals are able to move about freely as their blood samples usually differ from their other DNA samples taken from different parts of the body. It is also becoming difficult for the crime justice system as well as the medical system to analyze the exact number of chimeras as it is very difficult with the increase in mut ations.