M1-Lecture3 Flashcards
Epigenetics and Health
DNA does not change throughout development or during adulthood - other than acquired mutations - including germline changes, epigenetic changes? T/F
True
Epigenetics tags arise during development of fetus as cells & tissues differentiate? T/F
True
Some genes can be turned on or off with epigenetic tags permanently or as needed? T/F
True
Three basic epigenetic marks that control gene expression, mention>.
DNA methylation, histone modification and non-coding RNAs.
Unlike DNA, epigenetic tags can be modified throughout life both in negative and positive ways with diet & environmental exposures. T/F
True
Epigenetic marks during embryonic development & programming state the roles:
Erasure & establishment of DNA methylation marks, genetic imprinting, X-chromosome inactivation, the development of pluripotent stem cells & differentiation of somatic cells.
Immediately following fertilization, paternal genome undergoes rapid methylation & histone modifications through active & passive mechanisms. T/F
True
What is demethylated gradually - new wave of embryonic methylation that establishes the blueprint for tissues of developing embryo? T/F
Maternal genome, True
The de novo DNA methyltransferase enzymes, DNMT3a & DNMT3b, restore DnA methylation beginning from blastocyst stage? T/F
True
Each cell has its own epigenetic pattern? T/F
True
When do maternal & paternal genome combine in the same cell and DNA methylation and reprogramming occur to erase epigenetic patterns to establish totipotent state.
After fertilization
Although after fertilization, paternal & maternal combine and DNA pattern is erased, some genes remain “imprinted” with methyl marks (parent of origin) & maintained throughout the life of the offspring. T/F
True
Define imprinted genes?
Genes whose expression is determined by the parent that contributed them.
How do imprinted genes violate the rule of inheritance?
Both alleles in a heterozygote are equally expressed, but not in this case. One gene may be silenced based on parental origin.
Assisted reproduction or cloning may impose inherent risks to normal development? T/F
True
Cloning experiments procedure:
Nucleus of somatic cell must be reprogrammed to epigenetic state of an embryonic nucleus.
Genes in somatic cells must be silenced, while those needed for embroynic deve. must be activated.
Epigenetic defects may indicate that donated nucleus is not efficiently programmed.
During cloning how to ensure the egg does not contribute any genetic material?
By removing the nucleus
During cloning, why does the egg come from a different sheep?
To minimize immune system reaction. The immune system is less likely to react to an egg from a different sheep b/c it’s not familiar with proteins & signals present in the egg. It’s less prone to identifying it as “self” - lower chance of immune response.
What have been viewed as an attractive tool to prevent pediatric developmental diseases and cancer as well to delay aging-associated processes?
Nutritional epigenetics
Gene silencing through targeted nutrition allows epigenetic mechanisms of action to prevent or delay onset of inherited health problems and improve quality of life. T/F
True
Nutrition and environmental factors affect epigenetic inheritance of future generations? T/F
True
What is the study of food & food constituents on gene expression.
Nutrigenomics
Mentions a few examples as to how mutations affect how we process food:
PKU, lactose intolerance,
Alcohol flush reaction (mutation in gene impair processing of alcohol) resulting in skin flushing & intoxication.
Animal studies show that A diet with too little methyl-donating folate or choline BEFORE OR AFTER (long-term deficiency) birth causes certain regions of genome to be under-methylated for life. T/F
True
And for adults too, methyl-deficient diet leads to decrease in DNA methylation, but changes are reversible when methyl is added back to diet. T/F
True
Three factors that influence gut microbiota:
Maternal factors:
Maternal nutrition
Embryonic environment
Mode of delivery
Dietary patterns:
Breast feeding/formula diet
Diet enriched with fruits & vegetables/western diet
Environmental factors:
Lifestyle
Hygiene
Drugs/antibiotic exposure
Exercise
Geography
Host genetics
One-size-fits-all nutrition are inefficient & often ineffective. T/F
True b/c does not account for individual differences in needs and responses.
What can explain why same foods affect people differently?
Nutrigenomics
Proper nutrition can decrease risk of developing chronic diseases? T/F
True
What familiar nutrients are key components of methyl-making pathway?
Folic acid, B vitamins, SAM-e (S-Adensoyl methionine)
Today, more than 95% of chronic diseases are caused by food choice. T/F
True
Epigenetic changes can occur before, during, or after t he onset of a disease? T/F
True
Some epigenetic modifications can be reversible? T/F
True
What are the non-genetic factors besides epigenetics that affect the risk of T2DM?
Obesity, unhealthy diet, physical inactivity, ageing & intrauterine environment.
Obesity, unhealthy diet, physical inactivity, ageing & intrauterine environment. These have been associated with epigenetic modifications in healthy individuals? T/F
True