Lecture-9-DNA-modification- epigenetics

areexpressedatasingledosageinfemalesmalesandaneuploid

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Unformatted text preview: reversible •  Inactivegenessilencedinallthedescendentcells •  Afewgenesescapeinactivation ­‑activeonboth 23 XChromosomeInactivation regulatedthroughtheXistgene LocalizationofXist RNA(Green)on inactiveXchromosomes TheXISTgeneisexpressedonlyfrominactive, notfromactive,Xchromosomes. 24 TheinactiveXisseenasaBarrBody OnlyoneXchromosomeismaintainedintheactivestate XY XX or XXY XXX or XXXY XXXX or XXXXY XXXXX or XXXXXY BarrbodiesareheterochromaticXchromosomesthatfailto expressmostoftheirgenes. 25 XInactivation–IsRandom 26 Xinactivation FemalesaremosaicforX ­‑linkedgenemutations •  Thiswomanisaheterozygoteforamutationintheanhidrotic dysplasiagene. 27 XChromosomeInactivation: Abeautifulexample CalicoCat 28 XChromosomeReactivation Germline • PreviouslyinactivatedXchromo...
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