Identical twins have the same DNA and the same genes. They have many similarities such as resemblances in facial and body expression, their laugh, and much more. Despite these similarities, as these twins get older the differences that develop between their appearances can be remarkable. It is also very possible for one twin to get a deadly disease, such as cancer, while the other does not. The first question that may run through your mind is how? The answer is the epigenome. In contrast to the genome, which is the set of your entire DNA, the epigenome is what tells your genome what to do and when. In other words, if the genome is thought of as the hardware of the computer, with its physical parts being genes, the epigenome can be thought as the software of the computer, influencing how and when these physicals parts should be used. The epigenome also dictates the cell's behavior and function. The epigenome marks the genome, determining whether or not a gene is expressed and if so, to what level. It does this in two ways, DNA methylation, and histone modification. DNA methylation is where a methyl group, a tag of carbon and hydrogen, connects to a part of DNA (to the gene) and decides for it to be expressed or not. Histone modification is where a chemical tag secures a histone, or a protein, and tightens or loosens the gene's coil around it to determine how greatly the gene is expressed. But what does the epigenome have to do with identical twins? A study done by Dr. Randy Jirtle (Duke University) gives a partial explanation. His study was based off of genetically identical mice. Although these mice were identical, some were fat and yellow while others were brown and skinny. This difference of weight and color was caused by ch... ... middle of paper ... ...o be more responsible about their actions, as their actions can make or break their children's (and grandchildren's) futures. It may be the prospective cure and a way to prevent cancer and a lot of other illnesses. With more knowledge and research about the epigenome, lives can be transformed. So even if that one twin does get diagnosed with cancer while the other doesn't, there will be a cure for him or her, so the two siblings can continue living their lives together. Works Cited "Epigenetics." PBS. PBS, 09 Jan. 0000. Web. 03 Apr. 2014. . Epigenetics. Perf. Hank Green. YouTube. YouTube, 22 Jan. 2012. Web. 04 Apr. 2014. . "Epigenomics Fact Sheet." National Human Genome Research Institute. N.p., 7 May 2012. Web. 04 Apr. 2014. .
Twins are truly fascinating from the time of separation of the embryo to birth; and still the complexity of twinning is not yet fully understood among the scientific world. Scientists have studied the human body from the time of prenatal development to birth, and still are in awe of the formation of twins. Research in twinning is ever more increasing in this field, leadi...
-Reilly Philip. Is It In Your Genes. Cold Spring Harbor Laboratory Press. 2004: 223-228. Print
Histone modification may or may not be dependent on DNA methylation and is difficult to detect compared to LOH.
Hall, Linley Erin. “Understanding Genetics DNA and RNA.” New York: The Rosen Publishing Group, Inc., 2011. Print. 01 Apr. 2014.
Cancer is beyond mutations. By definition, epigenetics is the change in gene translation that is caused by alterations not directly due to genetic mutations in the DNA sequence. The 2 main mechanisms are DNA methylation and covalent modification of histones. By methylation, certain molecular tags (methyl groups) bind to a specific sequence of a gene, that results in its disability hence incapable of being translated into its appropriate protein product. These changes affect the cell’s functions leaving its DNA unchanged. Epi is derived from Latin meaning above; hence an epigenetic configuration overlies our genetic predispositions.
Lewis, Ricki, (2014), Human Genetics, 11th Edition, Chapter 12. Gene Mutation. [VitalSource Bookshelf Online]. Retrieved from
A major mechanism in epigenetics is DNA methylation. DNA methylation occurs in two mechanisms and is the addition of a methyl (-CH₃) group through a covalent bond to a cytosine side chain. DNA methylation is catalysed by a group of enzymes called DNA methyltransferases (DNMTs). DNMT adds methyl groups to cytosine residues. Cytosines have to be immediately followed by a Guanine In order to be methylated, these are called CpG dinucleotides. Around 70% of these dinucleotides get methylated whilst the rest are in clusters called CpG islands. There are two typ...
One of the most commonly described mechanisms is altered DNA methylation, which has been noted in paternal folate deficiency7, maternal under-nourishment during pregnancy6,7, paternal high fat diets2, and paternal low protein diets3. Another mechanism is established by microRNA’s ability to regulate DNA methylation. Certain microRNA’s are known to downregulate DNA methyltransferase enzymes that function to maintain global methylation status in the genome.6 It has been proposed that environmental exposures, like nutrition, can change sperm microRNAs leading to modifications in DNA methylation.11 Histone modifications in spermatids, such as acetylation, occur in another commonly described mechanism. These diet related changes affects the structure of chromatin, which can lead to increased risk damage to DNA and thus poor sperm outcomes.6 Further influences that lead to epigenetic changes during spermatogenesis include the following: increased testicular temperature, hyperleptinemia, hyperinsulinemia, and genotoxic metabolites due to paternal fat accumulation causing increased oxidative injury to sperm cell DNA.6 These epigenetic changes are thought to influence and accelerate genetic variation that is thought to drive the evolution of a
I have always been fascinated by conjoined twins and have always had questions about them like; what do the Siamese have to do with conjoined twins? Why does this form of twin happen? What, if any genes cause this? What types of Conjoined twins are there? How does the environment affect, if at all, the biological families' gene pool? In my research in efforts to prepare this paper, I found the answers to this question and many more. This term paper will cover the types of conjoined twins, the biological occurrence that causes conjoined twins, a look into some of the genetic and environmental causes of conjoined twins, the types of conjoined twins and the genetic and social impact of conjoined twins.
There are thirteen standard tandem repeats used in modern forensics, and together these sequences create a DNA profile. Except in the case of identical twins, the probability that two people have the same genetic code at all thirteen core loci is less than one in one trillion (Jones, 2004). Investigators compare these...
I remember that at an early age that I was never alone, whether the reminder comes from family or strangers, I have always had a constant reminder that helped me to feel safe in the world, but in other people’s eyes, I am not an individual but I am only a half of a whole. When I was little there was a time when I didn’t know that being a twin, an identical twin at that, would hinder my growth as an individual. According to Burke, when asked what makes you unique her reply was “I don’t know”, followed with “because I have a twin.” When asked to elaborate as to why she doesn’t know, her response was “we’re compared and seen as the same person even though in some ways i’m different from her, like the fact that I was born with my own brain and
Epigenetics also can be responsible for changes of histone, the main protein component of chromatin, which is a combination of DNA and protein to make the nucleus of a cell.
National Institute of General Medical Sciences. (2010). "21st-Century Genetics." The New Genetics, p. 74-83. Retrieved from http://publications.nigms.nih.gov/thenewgenetics/chapter5.html
Doppelgängers are two or more people who look alike. The human genome consists of over 3.2 billion base pairs. These base pairs can combine to make one gene, such as hair color or eye color. Genes are what we are made of, and they give us all different characteristics. But with around 7 billion people on the planet, there is bound to be more than one common gene between two people. This doesn’t include the deceased or unborn.
Developing organisms have a wide range of susceptibility to epigenetic changes. Inapt setting up of