Ph.D Fernando, Harvard Professor of Genetic Epidemiology, knows a thing or two about Twins. He must know as he is head of the Twin Research Department where he works with about 3,500 pairs of identical twins, researching the influence of a person's genes on everything from the probability of being obese, whether or not they have religious beliefs, and, how, do they fall into sentimental issues. Anyone who is a twin, or who has ever met a pair of identical twins, can attest to how remarkably similar they are to each other, even in the rare cases of adopted twins raised in separate homes. A recent article begins with an introduction to two middle-aged twin sisters called Susan and Polly, one of the pairs of twins in the study group of the Department of Research of Harvard. Although they were treated almost as a single person growing up, with cuts from identical hair and clothes, the twins began to diverge in their teens as they they gained the freedom to make their own choices. They started to dress in a way quite different, with Susan choosing much more conservative styles than Polly. Susan if describes as being shy, while Polly has always been more confident. Susan suffers from depression, but Polly didn't. Since they were born with exactly the same DNA and were raised in the same house, where do these differences come? In public debates about why people are who they are, a phrase of effect that often emerges is 'nature vs. creation': people argue, in other words, on the relative influence of a person's genes vs. the influence of the environment in which they live. At the In the case of Susan and Polly, it can be assumed that the 'nature' is identical and since they grew up in the same home, the "creation" side of the equation should also be quite similar. It turns out that the 'nature' component may not be so identical after all. based on your work with twins, Fernando now thinks that subtle changes in Susan and Polly's DNA after the conception - and indeed, throughout their lives - can be much more important and determining of his physical and psychological characteristics than he previously believed. As we age from children to adulthood, some of our DNA bases are modified by methylation: in other words, a methyl group (CH3) replaces a hydrogen. In humans and other mammals, this happens mainly with the cytosine bases (C), while in the bacteria is mainly adenosine (A) bases that are methylated. The S-adenosyl Biomolecule methionine, or 'SAM' for short, is important in this process. In mammals, gene methylation appears to occur in different patterns in different people -even in identical twins - in response to environmental factors. Methylation also seems have the effect of amplifying or silencing the function of a gene, altering the way it interacts. with regulatory proteins. The combined effect of many gene methylation events can be profound, as groups of interrelated genes are "increased" or "decreased" in set. Professor Fernando thinks that the many differences between Susan and Polly probably result,at least in part, from differences in how their genes have been methylated over their lifetimes thus far. 1 Given these premises, it is clear that a very important class of reactions from Nucleophilic substitutions in biochemistry are SN2 reactions catalyzed by the enzyme Sadenosyl-methionine, or SAM. Introduce the mechanisms of the reaction of SAM with adenine and with cytosine. Identify the nucleophile, electrophile and leaving group
reference text
Ph.D Fernando, Harvard Professor of Genetic Epidemiology, knows a thing or two about Twins. He must know as he is head of the Twin Research Department where he works with about 3,500 pairs of identical twins, researching the influence of a person's genes on everything from the probability of being obese, whether or not they have religious beliefs, and, how, do they fall into sentimental issues. Anyone who is a twin, or who has ever met a pair of identical twins, can attest to how remarkably similar they are to each other, even in the rare cases of adopted twins raised in separate homes.
A recent article begins with an introduction to two middle-aged twin sisters called Susan and Polly, one of the pairs of twins in the study group of the Department of Research of Harvard. Although they were treated almost as a single person growing up, with cuts from identical hair and clothes, the twins began to diverge in their teens as they they gained the freedom to make their own choices. They started to dress in a way
quite different, with Susan choosing much more conservative styles than Polly. Susan if describes as being shy, while Polly has always been more confident. Susan suffers from depression, but Polly didn't.
Since they were born with exactly the same DNA and were raised in the same house, where do these differences come? In public debates about why people are who they are, a phrase of effect that often emerges is 'nature vs. creation': people argue, in other words, on the relative influence of a person's genes vs. the influence of the environment in which they live. At the In the case of Susan and Polly, it can be assumed that the 'nature' is identical and since they grew up in the same home, the "creation" side of the equation should also be quite similar.
It turns out that the 'nature' component may not be so identical after all. based on your work with twins, Fernando now thinks that subtle changes in Susan and Polly's DNA after the conception - and indeed, throughout their lives - can be much more important and determining
of his physical and psychological characteristics than he previously believed. As we age from children to adulthood, some of our DNA bases are modified by methylation: in other words, a methyl group (CH3) replaces a hydrogen. In humans and other mammals, this happens mainly with the cytosine bases (C), while in the bacteria is mainly adenosine (A) bases that are methylated. The S-adenosyl Biomolecule
methionine, or 'SAM' for short, is important in this process.
In mammals, gene methylation appears to occur in different patterns in different people -even in identical twins - in response to environmental factors. Methylation also seems have the effect of amplifying or silencing the function of a gene, altering the way it interacts.
with regulatory proteins. The combined effect of many gene methylation events can be profound, as groups of interrelated genes are "increased" or "decreased" in set.
Professor Fernando thinks that the many differences between Susan and Polly probably result,at least in part, from differences in how their genes have been methylated over their lifetimes thus far.
1 Given these premises, it is clear that a very important class of reactions from Nucleophilic substitutions in biochemistry are SN2 reactions catalyzed by the enzyme Sadenosyl-methionine, or SAM. Introduce the mechanisms of the reaction of SAM with adenine and with cytosine. Identify the nucleophile, electrophile and leaving group
Step by step
Solved in 4 steps with 2 images
