epigenetics

Question 1

define epigenetics

Answer 1

Chemical modifications to the DNA and DNA-associated structures that do not change the DNA sequence, but can regulate gene expression and can be inherited across mitotic cell division

Question 2

list seven key epigenetic modifications

Answer 2

DNA methylation, histone marks, promoter binding, enhancer binding, chromatin structure, position relative to nuclear lamina, chromatin interactions

Question 3

name 3 atlases which can be used to look up epigenetic data to assist clinicians

Answer 3

The ENCODE Project
NIH Epigenome ROADMAP
The BLUEPRINT Project

Question 4

describe process of dna methylation what, enzyme does it use and what part of dna does it act on commonly?

Answer 4

5MC and methyltransferase

Question 5

why is 5 methyl cytosine commonly methylated

Answer 5

most stable human marker

Question 6

what context does 5mc occur in mammals specifically humans

Answer 6

cpg island

Question 7

what are the Roles of DNA methylation in normal development and over the life course

Answer 7

Gene expression regulation ‣ Reprogramming: cell lineage & tissue differentiation ‣ Genomic stability ‣ Genomic Imprinting ‣ X-chromosome inactivation ‣ Human Disease

Question 8

if cpg cluster/island is in promoter region is gene likely to be on or off

Answer 8

likely to be switched off methylation in this area often results in this, whereas in gene body can cause switching on of gene

Question 9

if gene is paternally imprinted which allele is expresses maternal or paternal

Answer 9

paternal therefore turned off so maternal

Question 10

What are the symptoms of prader willi syndrome

Answer 10

constant hunger, obese, short stature, small hands and feet, mild mental retardation

Question 11

What causes Prader willi syndrome

Answer 11

Maternal UPD because paternal gene is imprinted need father allele to function or 15q11 deletion

Question 12

symptoms of Angelmans syndrome

Answer 12

happy disposition, wide mouth, gaps between teeth, mentally retarded severe, jerky movements

Question 13

what uniparental disomy can cause angelmans syndrome

Answer 13

paternal upd

Question 14

what are symptoms of beckwith wiedemman syndrome

Answer 14

Overgrowth Cancer pre-disposition Macrosomia (large birthweight) Macroglossia (large tongue), prominent eyes Accelerated bone age Growth asymmetry Enlargement of kidneys, liver, pancreas, and spleen Neonatal hypoglycemia (30%) Cardiovascular defects

Question 15

what causes bws

Answer 15

Dysregulation of imprinting control regions on chromosome 11

Question 16

what has been noted in IVF births with regards to BWS

Answer 16

increased incidence

Question 17

describe some symptoms of silver Russel syndrome

Answer 17

triangular face, growth asymmetry especially of limbs, a lot of minor malformations, small in curved fifth fingers

Question 18

what causes silver Russel syndrome

Answer 18

First human disorder with imprinting disruptions affecting two or more different chromosomes (chromosome 7 and 11).

Question 19

what is X chromosome inactivation

Answer 19

it is the random silencing of one of the x chromosomes in each of the cells in order for female development to proceed. dosage compensation

Question 20

state some diseases that random x inactivation has been associated with

Answer 20

haemophilia, Fragile-X syndrome, and Duchenne Muscular Dystrophy

Question 21

what has gwas found in study of cancers

Answer 21

cancerous cells have gross change in epigenetic structure

Question 22

why is it important to control child exposure to risk factors

Answer 22

Exposures in development (prenatal, foetal, and postnatal) lead to greater susceptibility to human disease in later life

Question 23

what does maternal smoking during pregnancy do

Answer 23

can induce epigenetic changes causes epigenetic disease and congenital defects as a result

Question 24

what does poor nutrition do to foetus

Answer 24

Dutch Hunger Winter Study: food restriction in utero has adverse effects on metabolism and cardiovascular health, and age-associated decline of cognitive functions2. Epigenetic analyses show persistent epigenetic changes associated with prenatal exposure to famine