chapter 16

the inactivation of an x chromosome occurs in

female mammals on

which of the follwoing is an example of epigenetic inheritance

methylation of DNA that occurs in a oocyte

Genes that are expressed but do not encode polypeptides produce __ __ RNAS

non coding

chromating remodeling

nucleosomes rearrangement may increase expression of tumor suppressor genes

promote cancer by increasing transcription of genes that regulate cell division

oncogenes

in maize the red1* allele can change the expression level of red1 allele. the allele red1* allele is the _ allele

paramutagenic

mice that are homozygous for the loss of function mutation in the agouti gene wil have black fur becauee

pheomelanin is not produced

Covalent histone modification

promotes cancer by inhibiting tumor supressor genes or increasing the expression of oncogenes

the drug 5 azacytidine and decitabine which inhibit DNA methyltransferase have shown some improveent for patients with leukemia. one possible explanation is that

reducing DNA methylation allows tumor suppressor gene expression to reduce cell division

the lgf2 gene will be expressed if

the legf2 gene can be simulated by the enhancer, the ICR and DMR are methylated

which of the following facotrs determine the effects of paramitation

the rate of paramutation of the paramutagenic allele the stability of the paramutagenic allele

the PcG complex attaches hree methyl groups to lusine at position 27 in histone H2 in the process known as __. this mark represses geen expression

trimethylation

which two complexes are the key regulators of epigenetic chaanges that occur during delevopment

trithorax group, polycomb group

A statistically significant correlation coefficient means that

two variables have a true association

THe process by which some species of plants must be exposed to cold prior to flowering is called

vernalization

which of the following statements regarding x inactivation are true

when the xist gene is inactive the x chromosome is active in very early embryos both x chromosmes are active expression of Tsix from both x chromosmes inhibits the ecpression of x ist

the annual flowering lant arabidopsis thaliana has two different types. only __ require vernalization for flowering

winter annuals, which grow from fall to spring

mice with a gain of function mutattion in the agouti gene will have __ fur

yellow

if a correlation coefficient suggests a postitive correlation between DNA methylation and disease severity, then possible explanations could be that

* an enviornmental agent produced both DNA methylation and the disease independently * DNA methylation cause the diease * the disease leads to changes in DNA methylation

after vernalization plants

* have aquired epigenetic modifications in their genome *have the ability to flower when conditions are favorable

after vernalization, plants

* have the ability to flower when conditions are favorable * have acquired epigenetic modification in their genome

Which of the following are examples of epigenetics

* localization of histone variants *covalent histone modification *chromatin remodeling *DNA methylation

which changes occur follwoing the binding of xist rnas to the xi

*covalent modification of specific sites in hsitone tails * Recruitment of dna methyltransferases to XI *histone variant macroH2A is incorporated into the nuclosomes along the XI * recruitment of protein complexes to XI

mutations in chromatin modifiying proteins may contribute to cancer causing

*open chromatin to overexpress oncogenes *closed chromatin to inhibit expression of tumor suppressors

list the steps of how a gene may targete for silencing by PcG complexes in the correct sequence putting the first step ontop

1. prebinding proteins to pre and recruits prc2 2. prc2 catalyzes trimethylation of lysine 27 in histone h3 3. transcription is inhibited by preventing binding of RNA polymerase and PRC1 may be recruited to inhibit transcription in various ways

order the steps in the regulation of FLC expression by exposure to cold temperatures

1. prolonged cold induces expression of VIN3 and COLD AIR 2, VIN and PRC2 form a compled 3. PPC2 binds to COLDAIR RNA as it is transcribed from within a FLC intron 4. VIN3/PRC2 complex methylates Histone H3 within the FLC gene FLC gene expression is repressed

list the events of X chromosome inactivation in the correct sequence, putting the first event at the top

1. x chromosomespair briedly beginning at the Tsix gene 2. all pulipotency factors and CTCFs are shifted to one of the two x chromosomes 3. the Tsix gene of the chromosome without pluripotency factors and ctcf is inhibited; the inactivated chromosome is coated with xist RNA 4. Xist rna recruits proteins that epigeneticallt modify specific sites within the Xi

The protein __ hich represses genes required for flowering in the winter annual type of arabidopsis is inhibited by prolonged exposure to cold

FLC

the x inactivation center consist of which two genes

Tsix Xist

uncontrolled cell division may result from

a decrease in the expression of tumor suppressor genes

a paramutation is a

a genetic interaction in which one allele induces a heritable change in the other allele

trithorax group complexes epigenetically influenece development by __various genes

activating

DNA methylation

alteration of cpg islands inhibiting expression of tumor suppressor genes

trans-epigenetic mechanisms are more commonly found in

bacteria single celled eukaryotes

adult wild type mice with genotype AA for the agouri gene will have what color coat hairs

brown with balck tips

how do chemicals found in cigarette smoke induce cancer

by mutating genes by causing epigenetic changes

a genetic disease in which cells divide uncontrollably is

cancer

the mehtylation of a previously unmethylated site is clled

de novo methylation

what accounts for the variation in coat color in the mice shown

degree of methylation at CpG islands in the TE upstream from the Agouit gene

x chromosome inactivation is an epigenetic event that occurs during

embryogenesis

what term explains the variation of gene expression that is not related to the variation of the DNA, is transmissible and is reversible

epigenetics

because epigenetics refers to heritable change in gene expression all epigenetic changes are examples of transgenerational epigenetic inheritance

false

smoking cigarettes induces the formation of lung cancer only by causing genetic mutations in tumor suppressor genes

false