Final: Epigenetic Inheritance

Question 1

adult cells are highly _____

Answer 1

differentiated states with specific genes turned on or off

Question 2

when an adult cell divides…

Answer 2

it passes on the status of every gene to daughter cells

Question 3

5 aspects of gene regulation passed on

Answer 3

histone variants and modifications

DNA modifications (methylation of cytosines)

chromatin binding proteins (TFs)

chromatin structural RNA

Question 4

genetic inheritance

Answer 4

a dividing cell passes on its genes to daughter cells

this means the DNA sequence only

Question 5

epigenetic inheritance

Answer 5

a dividing cell also passes on the regulatory status of each gene

all regulatory mechanisms are passed on to daughter cells

Question 6

what is a barr body an example of

Answer 6

epigenetic inheritance

barr body replicates and is passed on, then turns into a barr body again

Question 7

how do daughter cells stay the same as parent cells?

Answer 7

the genes “remember” what they were doing before

so they keep doing it in the daughter cells

epigenetic inheritance

Question 8

4 things the daughter cells end up having

Answer 8

same histone modifications

same cytosine methylations

same bound TFs

same bound regulatory RNA

Question 9

2 pathways to epigenetic inheritance

Answer 9

from cell to cell within a body

from parent to offspring between generations

Question 10

genomic imprinting

Answer 10

parent-to-child epigenetic inheritance

causes the same allele to have different effects

effect depends on the sex of the parent transmitting the allele

same gene can be “pre-methylated” two different ways in eggs or sperm

Question 11

DMR

Answer 11

differently methylated region

regions of DNA that are methylated one way in eggs and another way in sperm

Question 12

genomic imprinting occurs in the ____

Answer 12

germline

offspring grows up keeping the methylation pattern of parents

parental imprinting is erased in germline of offspring

then the genes are re-imprinted according to the offspring’s own sex

Question 13

CpG island

Answer 13

genomic imprinting in mammals involves methylation of CpG islands

there may be additional mechanisms for epigenetic inheritance in gametes

Question 14

IGF2

Answer 14

protein hormone that promotes fetal growth

mother’s copy is shut down by methylation

father’s copy does all the work

it doesn’t matter if the mother’s copy gets mutated

if father’s copy is mutated then you don’t grow right

Question 15

Beckwith Wiedemann Syndrome

Answer 15

same genes are in mice chromosome 7 and human 11

loss of mother’s copy causes BW syndrome

paternal homolog already shut down

Question 16

Prader Willi Syndrome and Angelman Syndrome

Answer 16

2 genetic diseases coming from 1 genetic region

PW leads to extreme appetite and obesity

Angelman leads to hyperactivity

to be normal, inherit one imprinted copy of DMR from each parent

Question 17

how get Prader Willi

Answer 17

inherit only mothers DMR

Question 18

how get Angelman

Answer 18

inherit only fathers DMR

Question 19

causes of Prader Willi

Answer 19

paternal deletion

paternal methylation defect

maternal uniparental disomy (2 copies of maternal #15)

Question 20

causes of Angelman

Answer 20

maternal deletion

maternal methylation defect

paternal uniparental disomy (2 copies of paternal #15)

Question 21

uniparental disomy

Answer 21

a person has normal diploid # of chromosomes (46)

but for one pair of homologs, both copies came from just 1 of the parents

Question 22

how does uniparental disomy occur

Answer 22

trisomic zygote sorts into disomy in early division of embryo

disomic gamete could meat a nullisomic gamete

monosomic zygote duplicates in early division

Question 23

DMRs

Answer 23

to be normal you need:

one haploid set of male imprinted chromosomes

one haploid set of female imprinted chromosomes

Question 24

all mammals use genomic imprinting but not on all ____

Answer 24

genes

Question 25

most genes are not in ___, so these problems dont arise with them

Answer 25

DMRs

Question 26

can environmental factors negatively affect genomic imprinting?

Answer 26

yes: in vitro fertilization multiplies rate of BW syndrome 3-4x
also: exposing pregnant rats to fungicide Vinclozolin causes epigenetic effects

passed on several generations but only in males