Trigger 8: Environmental impact on epigenetic profile Flashcards
genome can acquire/ lose methyl group
much more readily than it change its DNA sequence
dynamic natur eo epigenome provides mechanisms by which organism can response to the environment without
changing hardware
when is the epigenome particularly susceptible to deregulatio
embryogenesis
perinatal period
why are embryogenesis
perinatal period susceptible to epigenetic changes
- DNA synthesis rate is high
- time when elaborate DNA methylation patterns and chromatin structure required for normal tissue development are established
DNA sequence is
very stable
epigenetic process an be
highly dynamic
agouti mouse
colour of mouse is manipulated by diet of mother (yellow mouse or agouti)
yellow mouse
- high risk of cancer, diabetes, obesity
- reduced life span
–> LTR gene s hypomethylated
agouti mouse
- lower risk of cancer, diabetes, obesity
- prolonged life
- LTR is hypermethylated
dutch hunger winter 1944-45
individuals who were prenatally exposed to famine, 6 decades later, had less DNA methylation of the imprinting IGF2 gene, compared to their unexposed, same-sex siblings
imprinting on IGF2 gene
higher risk of obesity/cvd and diabetes
early-life (in the womb) environmental conditions
can cause epigenetic changes in humans that persist throughout life
other factors which effect the genome
diet medication hormones drugs of abuse radiation psychosocial factors climate
critical periods of sensitivity
foetal development
transgeneration epigenetic inheritance
epigenetic disorders can be passed on
example of transgeneration epigenetic inheritance
Grandparent develops transcriptional dysregulation due to environmental factors (smoking, drinking, poor diet), child inherits epigenetic disorders
what can stop epigenetic dysregulation
epigenetic based therapy
multigenerations vs transgeneration
mother is 1st generation
fetus is 2nd generation
what is third generation
reproductive cells of 2nd generation fetus
thought that trauma
can be passed onto children’s genes e.g. children of holocaust survivors
when loci resist reprogramming by transcriptisome…
imprinting
transgenerational inheritance
the impact of the environment has been obsessed to extend over multiple generations, suggesting transgenerational epigenetic effects- defined mechanism is missing
epigenome is
erased prior to implantation of a blastocyst, followed by the establishment of new functional epigenetic signature (exception of imprinted regions
if true epigenetic inheritance is to occur
then some epigenetic marks must be resistant to both of these reprogramming events
