epigenetics Flashcards
define epigenetics
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
list seven key epigenetic modifications
DNA methylation, histone marks, promoter binding, enhancer binding, chromatin structure, position relative to nuclear lamina, chromatin interactions
name 3 atlases which can be used to look up epigenetic data to assist clinicians
The ENCODE Project
NIH Epigenome ROADMAP
The BLUEPRINT Project
describe process of dna methylation what, enzyme does it use and what part of dna does it act on commonly?
5MC and methyltransferase
why is 5 methyl cytosine commonly methylated
most stable human marker
what context does 5mc occur in mammals specifically humans
cpg island
what are the Roles of DNA methylation in normal development and over the life course
Gene expression regulation ‣ Reprogramming: cell lineage & tissue differentiation ‣ Genomic stability ‣ Genomic Imprinting ‣ X-chromosome inactivation ‣ Human Disease
if cpg cluster/island is in promoter region is gene likely to be on or off
likely to be switched off methylation in this area often results in this, whereas in gene body can cause switching on of gene
if gene is paternally imprinted which allele is expresses maternal or paternal
paternal therefore turned off so maternal
What are the symptoms of prader willi syndrome
constant hunger, obese, short stature, small hands and feet, mild mental retardation
What causes Prader willi syndrome
Maternal UPD because paternal gene is imprinted need father allele to function or 15q11 deletion
symptoms of Angelmans syndrome
happy disposition, wide mouth, gaps between teeth, mentally retarded severe, jerky movements
what uniparental disomy can cause angelmans syndrome
paternal upd
what are symptoms of beckwith wiedemman syndrome
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
what causes bws
Dysregulation of imprinting control regions on chromosome 11
what has been noted in IVF births with regards to BWS
increased incidence
describe some symptoms of silver Russel syndrome
triangular face, growth asymmetry especially of limbs, a lot of minor malformations, small in curved fifth fingers
what causes silver Russel syndrome
First human disorder with imprinting disruptions affecting two or more different chromosomes (chromosome 7 and 11).
what is X chromosome inactivation
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
state some diseases that random x inactivation has been associated with
haemophilia, Fragile-X syndrome, and Duchenne Muscular Dystrophy
what has gwas found in study of cancers
cancerous cells have gross change in epigenetic structure
why is it important to control child exposure to risk factors
Exposures in development (prenatal, foetal, and postnatal) lead to greater susceptibility to human disease in later life
what does maternal smoking during pregnancy do
can induce epigenetic changes causes epigenetic disease and congenital defects as a result
what does poor nutrition do to foetus
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
