3.3/4 APPLIED LEC

Question 1

what is the epigenome

Answer 1

chemical modifications of dna that alter gene expression and contribute to regulation

modifications include histone tail modifications and DNA methylation

Question 2

cancerous cells and the epigenome

Answer 2

cancer isn’t just mutations in the genome, epigenetic factors contribute to cancerous cells

• cancerous cells heavily methylate genes not convenient to them, including the stop checkpoint switch
• cancer cells have abnormal epigenomes, may upregulate or down regulate genes

Question 3

what is the significance of agouti mice

Answer 3

First studied the epigenome

the agouti gene which is the colour gene of the mice is heavily methylated in the brown mice and not in the yellow mice

these methylation patterns are further applied to other genes within the mice
genes causing improper digestion of sugar and expression of tumours are unmethylated in yellow mice, and methylated in brown mice

Question 4

can epigenetic fate be reversed

Answer 4

yes, yellow mice moms were given supplimented methyl verses normal mice chow

normal chow diet mothers birthed more yellow pups

methyl supplimented (b12, choline, folic acid) diet mothers birthed more brown pups

it was found that as the concentration of methyl supplements in diets of these mother yellow mice increased, an increase in the number of brown pups born was observed

aqouti gene methylation increased with increased supplemented diets

Question 5

spina bifida and epigenomes

Answer 5

mothers with an increased folic acid consumption after the 1970s were less likely to have babies born with spina bifida due to methylation of certain related genes

Question 6

will monozygotic twins have the same epigenome?

Answer 6

No
monozygotic twins- two individuals from one fertilized egg

twins can look different as they age due to different lifestyle factors (diet, exercise, marriage) which could influence how their proteins pick up signals to regulate gene expression through methylation and epigenetic modifications

chronic smoker twins have different phenotype (expression of genes) and epigenetic modifications

a study examined the methylation differences in chromosomes of twins at different ages

younger twins: exposed to the same environment, have similar methylation across chromosomes

older twins: have different dna methylation patterns, where red (fluorescent tag of methylation of twin a) and green (fluorescent tag of methylation of twin B chromosome) are visible instead of yellow

greater difference between genes that are on and off in older twins

Question 7

epigenetic drift

Answer 7

The drift from an inherited epigenome as an individuals epigenome varies with life stylistic factors

Question 8

Dr Parminder Raina research

Answer 8

studying epidemeolgy of aging and disease considering different socioeconomic status, environmental factors

studying genes susceptible to epigenic alteration with aging