lecture 30 Flashcards
epigenetics
what is the genetic material of an organism called?
genome
what is the record of the chemical changes to the DNA and histone proteins of an organism called?
epigenome
at what point in development are epigenetic tags erased from parental chromsoomes?
the first few days after fertiliizaton
what are the epigenetic tags that are left after most are erased called?
imprinted genes
what transfers epigentic information rather than just DNA sequences to offspring?
imprinted genes
what do epigenetic tags do during cell specialization in an embryo?
they either activate or silence gene sequences which leads to further specializaiton
what is different at a genetic level in identical twins once they reach adulthood and why?
epigenome patterns because they are affected by environmental factors
do epigenetic tags change the genetic code?
no
how do epigenetic tags affect gene expression?
methylation and chromatin remodeling
what does methylation do to transcription in eukaryotic genes?
it silences it, especiallly in promotor region
what are CpG islands?
sequences of DNA(~1000-2000 nucleotides long) with a lot of CG repeats located near promotor regions
how are housekeeping genes expressed?
constitutively(all the time)
are CpG islands methylated or unmethylated in housekeeping genes?
unmethylated
where is tissue specific gene expression regulated?
at CpG islands (by methylation)
where does a transcriptional activator bind?
to the enhancer located in the CpG island located before the core promotor which is before the coding sequence (of unmethylated DNA)
wat blocks transcriptional activator binding?
methyl groups on CpG island near enhance
what does methyl-CpG do?
it binds to the methyl groups that have been added to the DNA, thereby coiling it, resulting in heterchromatin
what is lyonization?
inactivation of one random X chromosome to not produce twice the gene product
what is a Barr body?
supercoiled X chromosome
what impacts the different color dispersions of Calico cats?
timing of methylation
how does diet influence epigenetics?
foods with folic acid and vitamin B have methyl donating nutrients that regulate gene expression
what is epigenetic memory?
the idea that epigenetic modification can be passed across generations(past F1)
how do methylation levels of cancer cells compare to those of healthy cells?
they are lower, activating genes that promote cell growth
