Trigger 9: Epigenetics in action Flashcards
during gametogenesis
epigenetic profile is rest to de novo
when genes evade reprogramming
imprinted from previous generations
uniparental disomy
people who inherit both homologous chromosomes from the same parents
what occurs due to uniparentald disomy
loss of expression of some genes that maternal alleles and increased levels of paternally expressed genes
UPD
uniparental disomy
UPD was hypothesised to
cause diseases due to changes in epigenotype and disruption of genomic imprinting
genomic imprinting
where alleles inherited from one parent are expressed differently to the other parents
- e.g. allele from father is inactive due to imprinting
during imprinting the alleles
behave normally in meiosis- only their expression in the offspring is altered
during imprinting what is meaningless
dominants- basically hemizygous
hemizyoug
. A chromosome in a diploid organism is hemizygous when only one copy is present
most common imprinting method
DNA methylation
where does de novo emthylase act only at
CpG islands
after DNA replication
DNA methylation is replicated DNMT1
freshly replicated DNA is methylated only
on one strand (hemi-methylated)
maintenance methylase
acts only at hemimethylated CG sites
will a change in phenotype occur if the maternal copy of gene is imprinted, but the paternal copy is normal
no
will a change in phenotype occur if the maternal copy of gene is imprinted and the paternal copy is mutated
yes
