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nidthamsirisup

Epigenetics: DNA Isn't Everything - 0 views

www.sciencedaily.com/...090412081315.htm

epigenetics genetics gene

shared by nidthamsirisup on 15 Apr 12 - Cached
  • Research into epigenetics has shown that environmental factors affect characteristics of organisms. These changes are sometimes passed on to the offspring.
  • A certain laboratory strain of the fruit fly Drosophila melanogaster has white eyes. If the surrounding temperature of the embryos, which are normally nurtured at 25 degrees Celsius, is briefly raised to 37 degrees Celsius, the flies later hatch with red eyes.
  • crossed the flies for six generations. In this experiment, they were able to prove that the temperature treatment changes the eye colour of this specific strain of fly, and that the treated individual flies pass on the change to their offspring over several generations. However, the DNA sequence for the gene responsible for eye colour was proven to remain the same for white-eyed parents and red-eyed offspring.
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  • Epigenetics examines the inheritance of characteristics that are not set out in the DNA sequence.
  • important factors are the histones, a kind of packaging material for the DNA, in order to store DNA in an ordered and space-saving way. It is now clear that these proteins have additional roles to play. Depending on the chemical group they carry, if they are acetylated or methylated, they permanently activate or deactivate genes.
  • New methods now allow researchers to sometimes directly show which genes have been activated or deactivated by the histones
  • The genetic information of the DNA is passed on along with the relevant epigenetic information for the respective cell type.
  • A similar question remains for the inheritance of the epigenetic characteristics from parents to offspring. They now know that when the gametes are formed, certain epigenetic markers remain and are passed on to the offspring. The questions, which are currently being researched, are how much and which part of the epigenetic information is preserved and subsequently inherited.
  • Diet and epigenetics appear to be closely linked. The most well known example is that of the Agouti mice: they are yellow, fat and are prone to diabetes and cancer. If Agouti females are fed with a cocktail of vitamin B12, folic acid and cholin, directly prior to and during pregnancy, they give birth to mainly brown, slim and healthy offspring. They in turn mainly have offspring similar to themselves.
  • Environmental factors, which change the characteristics of an individual and are then passed on to its offspring, do not really fit into Darwin’s theory of evolution. According to his theory, evolution is the result of the population and not the single individual. “Passing on the gained characteristics fits more to Lamarck’s theory of evolution”, says Paro.
Pop karnchanapimonkul

Dieting During Pregnancy Increases Risk Of Obesity And Diabetes For Offspring - 0 views

www.medicalnewstoday.com/...243627.php

dieting obesity diabetes epigenics offspring

shared by Pop karnchanapimonkul on 14 Apr 12 - No Cached
  • babies of mothers who diet around the time of conception and in early pregnancy, may have an increased risk of obesity and type 2 diabetes throughout their lives. This study provides exciting insights into how behavior can lead to epigenetic changes in offspring related to obesity and disease.
  • dieting around the time a baby is conceived may increase the chance of the child becoming obese later in life
  • changes in the genes that control food intake and glucose levels that may lead to obesity and diabetes.
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  • epigenetic changes with alterations in the structure of the DNA and its associated proteins, histones, which affects the way that genes can behave in later life.
  • Pop karnchanapimonkul on 14 Apr 12
     
    Article about how dieting during pregnancy cause offsprings to have a change in genes.
nidthamsirisup

Epigenetics Seeks Clues to Mental Illness in Genes' Life Story - Science in 2011 - NYTi... - 0 views

www.nytimes.com/...09brain.html

epigenetics DNA Genes disease

shared by nidthamsirisup on 15 Apr 12 - No Cached
  • epigenetics, the study of how people’s experience and environment affect the function of their genes.
  • Studies suggest that such add-on, or epigenetic, markers develop as an animal adapts to its environment, whether in the womb or out in the world — and the markers can profoundly affect behavior.
  • In studies of rats, researchers have shown that affectionate mothering alters the expression of genes, allowing them to dampen their physiological response to stress. These biological buffers are then passed on to the next generation: rodents and nonhuman primates biologically primed to handle stress tend to be more nurturing to their own offspring, and the system is thought to work similarly in humans.
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  • the offspring of parents who experience famine are at heightened risk for developing schizophrenia, some research suggests — perhaps because of the chemical signatures on the genes that parents pass on.
  • in some people with autism, epigenetic markers had silenced the gene which makes the receptor for the hormone oxytocin. Oxytocin oils the brain’s social circuits, and is critical in cementing relationships; a brain short on receptors for it would most likely struggle in social situations.
  • In one large study of people with schizophrenia, researchers at Johns Hopkins are analyzing blood and other data to see whether the degree of epigenetic variation is related to the inherited risk of developing the disorder. In another, researchers at Tufts are studying the genes of animals dependent on opiates to see how epigenetic alterations caused by drug exposure affect the opiate sensitivity of the animals’ offspring.
orasa sukmark

Cloned Meat & Milk Coming - 1 views

www.i-sis.org.uk/loned_Meat_and_Milk_Coming.php

meat milk coming Genes

shared by orasa sukmark on 16 Apr 12 - No Cached
  • Milk and meat from ‘cloned’ animals’ offspring could soon be on sale without any labels
  • The UK government has no objection to selling meat and milk from clones.
  • There are currently just over 100 offspring of cloned animals on British farms, but this will rise dramatically if the EC gets its way.
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  • According to BEUC, an overwhelming majority of EU consumers do not want cloning to be used for food production purposes. Some 84 per cent are concerned about the long-term health and safety impacts.
  • orasa sukmark on 16 Apr 12
     
    Cloned Meat and milk will be sold soon.
chanon chiarnpattanodom

Cancer epigenetics takes center stage - 1 views

www.pnas.org/...392.full

shared by chanon chiarnpattanodom on 16 Apr 12 - No Cached
    • chanon chiarnpattanodom
      chanon chiarnpattanodom on 16 Apr 12
       
      DNA methylation is a chemical process where a methyl group is added on either the cytosine ring or the adenine ring, used in "higher leveled" organisms. Important in cell differentiation since methylation will cause cells to "remember" and remain differenciated instead of expressing other genes. 
  • Epigenetics is defined as modifications of the genome, heritable during cell division, that do not involve a change in the DNA sequence.
  • Epigenetic alterations in cancer include global hypomethylation
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  • the promoters of housekeeping genes that are generally protected from methylation.
  • may lead to aberrant silencing of tumor suppressor genes
  • discovered loss of imprinting (LOI) in cancer
  • Genomic imprinting, the subject of the report by Nakagawa et al. (2), is an epigenetic modification of a specific parental allele of a gene, or the chromosome on which it resides, in the gamete or zygote, leading to differential expression of the two alleles of the gene in somatic cells of the offspring.
  • we found that LOI can occur in the normal colonic mucosa of colorectal cancer patients with LOI in their tumors
  • This LOI was linked to cases showing microsatellite instability (MSI) in the tumors
  • However, these patients do not have mutations in mismatch repair genes
  • One potential cause of MSI in these sporadic cancers is hypermethylation and epigenetic silencing of the hMLH1 mismatch repair gene
  • Nakagawa et al. (2) now confirm the original study of Cui et al. that LOI occurs in both tumor and normal tissue of patients
  • The present study (2) also offers an intriguing mechanistic hypothesis to explain the relationship between H19 DMR methylation and LOI in these patients
  • Nevertheless, the study calls attention to this remarkable highly conserved multifunctional protein,
  • The potential link to CTCF suggested by this study also calls our attention to the link among DNA methylation, epigenetics, and chromatin.
  • A clue to the link between MSI and epigenetics may be provided by another sometimes overlooked common thread in epigenetics, namely DNA replication
  • repeat-induced gene silencing is thought to be propagated through hemimethylated intermediates during DNA replication
  • The studies of Cui et al. (11), Nishihara et al. (20), and Nakagawa et al. (2) suggest a new and provocative view of the timing of epigenetic changes in cancer.
  • Studies of transgenic mice with constitutive biallelic expression of IGF2, comparable to LOI, show reduced apoptosis and increased tumor formation
  • I conclude by noting that the distinction between cancer genetics and epigenetics has blurred considerably in recent years
  • Many conventional “genetic” mechanisms directly affect proteins that regulate chromatin,
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