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Description
Flashcards by sophietevans, updated more than 1 year ago
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Created by sophietevans
almost 11 years ago
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| Question | Answer |
| List some observed epigenetic phenomena. | Caterpillars and butterflies are genetically identical but phenotypically incomparable. There are 70,000,000,000,000 cells in the human body with exactly the same DNA but which differentiate and then stay the same for a life time. Identical twins are genetically identical, but they are rarely truly identical in behaviour and appearance. |
| What is the significance of epigenetics in disease? | Abnormal patterns of modifications on our genes lead to cells developing the wrong patterns and combinations of gene expression and this contributes to disease. |
| What does the epigenome consist of ? | The DNA molecule wrapped around nucleosomes of histone proteins with chemical tags variably covering both. |
| What do methyl groups do? | Methyl groups tag cytosine nucleotides and result in DNA wrapping more tightly around histones, reducing expression of genes by preventing transcription machinery such as RNA polymerase from accessing the DNA. |
| What do acetyl groups do? | Acetyl groups bind to lysine amino acids and loosen the association between the DNA molecule and the histone proteins so that the genes are expressed more due to easier access by transcription machinery such as RNA polymerase. |
| List factors affecting the epigenome. | Diet, physical activity, stress, and exposure to toxins. |
| What are imprinted genes? | Epigenetic chemical tags which are not removed from parental DNA (as some others are) before transmission to offspring. |
| What is the advantage of epigenetics? | Information (such as high anxiety from predator presence) can be passed from one generation to the next more quickly than by evolution, and it being flexible and reversible means that an organism can adapt to new situations. |
| What are the slow growth periods in both sexes? | 8-10 years old in girls, 9-12 years old in boys. |
| What effect of grandfathers' food supply on the proband was found in the Overkalix study? | There was a deleterious effect on the survival of the proband if the paternal grandfather was 'overfed' at least once during a 'good' harvest in his slow growth period. Probands benefited from the paternal grandfather experiencing at least one 'poor' harvest during the slow growth period. These effects skipped a genertion and support the possibility of an intergenerational 'feedfoward loop'/genetic imprinting. |
| State a finding of the ALSPAC | Sons of fathers who had started smoking before age 11 had a greater BMI at age 9 than those whose fathers did not. |
| What features were associated with children and grandchildren of women exposed to the Dutch famine during pregnancy? | The children and grandchildren were smaller, shorter, had increased neonatal adiposity, and had a propensity towards atopic disease, autoimmune disease, cancer, and acquired neurological conditions. |
| What are some ethical implications of epigenetics? | Epigenetics may intensify obligations concerning lifestyle decisions, increasing blame arising from choice, produce liability for future illness in offspring, produce multigenerational liability for mortgages, employment or insurance, increase discrimination (?), disrupt privacy of information, highlight social inequalities and result in compensation being claimed for exposure to environmental risks! |
| What is epigenetics? | Epigenetics refers to any heritable effect on chromosome or gene function that is NOT accompanied by a change in DNA sequence. |
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