Epigenetics ho Taolo ea Liphatsa tsa Lefutso
Epigenetics ke lekala la baeloji le ithutang diphetoho tshebetsong ya dijini tse sa bakwang ke diphetoho tatellanong ya DNA. Ka mantswe a mang, epigenetics e hlalosa kamoo dijini di ka bulelwang kapa tsa tima kateng ntle le ho fetola khoutu ya dijini ka boyona. Kgopolo ena e bohlokwa hobane e re thusa ho utlwisisa hore na ke hobaneng ha disele tse mmeleng tse arolelanang DNA e le nngwe di ka ba le mesebetsi e fapaneng, jwalo ka disele tsa methapo, disele tsa mesifa le disele tsa madi. Epigenetics e bapala karolo e kgolo taolong ya dijini, tshebetso ya ho laola hore na jini e hlahiswa neng, hokae, le ka matla hakae.
Metheo ea Taolo ea Liphatsa tsa Lefutso
Taolo ea liphatsa tsa lefutso ke mokhoa oo lisele li o sebelisang ho fetola tlhahiso ea protheine ho latela litlhoko. Liphatsa tsa lefutso tse "mafolofolo" li fetisetsoa ho RNA ebe li fetoleloa ho liprotheine. Ka lehlakoreng le leng, liphatsa tsa lefutso tse "sa sebetseng" ha li hlahise lihlahisoa tse sebetsang. Taolo ena ea bohlokoa bakeng sa nts'etsopele ea lesea le sa tsoa emoloa, phapang ea lisele, karabelo ea khatello ea maikutlo, ho ikamahanya le tikoloho, le ho boloka mesebetsi ea 'mele. Ho sitisoa ha taolo ea liphatsa tsa lefutso ho ka lebisa mafung a fapaneng, ho kenyeletsoa kankere, mathata a metabolism, le mathata a nts'etsopele.
Moelelong ona, epigenetics e sebetsa joalo ka sistimi e 'ngoe ea taolo holim'a genome. Haeba genome e tšoana le buka ea diresepe, joale epigenetics ke letšoao kapa ntlha e khethollang hore na ke diresepe life tseo u lokelang ho li bala le hore na hangata hakae.
Mekhoa ea Bohlokoa ea Epigenetics
Mekhoa e mengata e meholo ea epigenetic e susumetsa taolo ea liphatsa tsa lefutso. Tse tharo tse ithutiloeng haholo ke methylation ea DNA, phetoho ea histone, le taolo ka RNA e sa ngoleng khoutu. Kaofela tse tharo li sebetsa ka mokhoa o hokahaneng ho laola phihlello ea DNA le maemo a tlhahiso ea liphatsa tsa lefutso.
1. Metsi a DNA
Metsi a DNA a etsahala ha sehlopha sa methyl (—CH₃) se eketsoa motheong oa cytosine, hangata libakeng tsa DNA tse nang le lipara tsa motheo tsa CpG (cytosine-phosphate-guanine). Ho eketsoa ha sehlopha sena sa methyl hangata ho amahanngoa le ho thibeloa ha tlhahiso ea liphatsa tsa lefutso. Libaka tsa bohlokoa ka ho fetisisa tsa methylation hangata ke li-promoter tsa liphatsa tsa lefutso, libaka tsa DNA tse laolang ho qalisoa ha phetolelo.
Haeba promoter e na le methylation e ngata, lintlha tsa transcription li thatafalloa ho kopana, 'me RNA polymerase e ke ke ea sebetsa hantle. Ka lebaka leo, gene e atisa ho "khutsa." Methylation ea DNA e bapala karolo ea bohlokoa lits'ebetsong tse tloaelehileng tse kang ho se sebetse ha chromosome ea X ho basali le ho kenngoa ha genomic, moo polelo ea gene e susumetsoang ke leloko la batsoali.
2. Phetoho ea Histone
DNA e ka hara nucleus ya sele ha e bole feela; ho ena le hoo, e kentswe mmoho le diprotheine tsa histone ho etsa chromatin. Sebopeho sena se ka ba thata kapa sa hlepha. Ha chromatin e tiile (heterochromatin), dijini ha di fumanehe habonolo mme ho ka etsahala hore di se ke tsa hlahiswa. Ha chromatin e hlepha (euchromatin), dijini di fumaneha habonolo mme ho ka etsahala hore di be mafolofolo.
Li-Histone li ka fetoloa ka mekhoa e fapaneng ea lik'hemik'hale, joalo ka acetylation, methylation, phosphorylation, le ubiquitination. Histone acetylation, haholo-holo li-residue tsa lysine, hangata e amahanngoa le ts'ebetso ea liphatsa tsa lefutso hobane e etsa hore chromatin e bulehe haholoanyane. Ka lehlakoreng le leng, histone methylation e ka baka ts'ebetso kapa khatello ho latela sebaka le palo ea lihlopha tsa methyl tse ekelitsoeng. Motsoako oa liphetoho tsena o etsa "khoutu ea histone" e thusang ho fumana boemo ba tlhahiso ea liphatsa tsa lefutso.
3. RNA e sa ngoleng khoutu
Hase RNA eohle e fetoleloang ho ba protheine. Li-RNA tse ngata tse sa ngoleng khoutu li phetha karolo taolong ea liphatsa tsa lefutso, ho kenyeletsoa li-microRNA (miRNA), li-RNA tse telele tse sa ngoleng khoutu (lncRNA), le li-RNA tse nyane tse sitisang (siRNA). Li-MicroRNA, mohlala, li ka khomarela li-mRNA tse reriloeng 'me tsa baka ho senyeha kapa ho thibela phetolelo, ka hona li fokotsa tlhahiso ea protheine.
Li-RNA tse sa ngoleng khoutu li ka boela tsa tataisa metsoako ea protheine ea epigenetic libakeng tse itseng ka har'a genome, ka hona tsa susumetsa methylation ea DNA kapa liphetoho tsa histone. Ka tsela ena, li-RNA tse sa ngoleng khoutu li sebetsa e le balaoli ba hlophisitsoeng hantle ba khethollang maemo a itseng a tlhahiso ea liphatsa tsa lefutso.
Epigenetics ho Nts'etsopele le Phapang ea Lisele
Karolo e 'ngoe e hlahelletseng ea epigenetics ke nts'etsopele ea lintho tse phelang. Ha zygote e ntse e hola ho ba mefuta e fapaneng ea lisele, sele ka 'ngoe e na le DNA e tšoanang empa e na le lenaneo le ikhethang la tlhahiso ea liphatsa tsa lefutso. Lenaneo lena le thehiloe le ho bolokoa ka matšoao a epigenetic.
Mohlala, disele tsa stem di na le chromatin e bulehileng haholo, e leng se dumellang dijini tse ngata ho kenngwa tshebetsong. Ha di ntse di kgetholla, matshwao a epigenetic a fokotsa kgetho ya dijini tse kentsweng tshebetsong, e leng se dumellang disele ho ba tse ikgethang, jwalo ka disele tsa sebete tse ntshang dijini tsa detoxification kapa disele tsa pancreatic tse ntshang dijini tse hlahisang insulin.
Tšusumetso ea Tikoloho ho Epigenetics
Epigenetics e boetse e koala lekhalo pakeng tsa liphatsa tsa lefutso le tikoloho. Mabaka a kang phepo e nepahetseng, khatello ea maikutlo, ho pepesehela chefo, ho tsuba, ho ikoetlisa 'meleng, esita le mekhoa ea ho robala a ka susumetsa matšoao a epigenetic. Mohlala, khaello ea limatlafatsi tse itseng tse sebetsang e le bafani ba methyl (joalo ka folate le vithamine B12) e ka ama mekhoa ea methylation ea DNA.
Ho pepesehela litšila kapa lik'hemik'hale ho ka boela ha fetola liphetoho tsa histone le methylation ea DNA, qetellong ea ama kotsi ea mafu. Lena ke le leng la mabaka a etsang hore mokhoa oa bophelo o ka susumetsa bophelo bo botle ba nako e telele, esita le boemong ba limolek'hule.
Epigenetics le Mafu
Ho se leka-lekane taolong ea epigenetic ho ka kenya letsoho mafung a fapaneng. Ka kankere, mekhoa ea methylation ea DNA hangata e feta liphetohong tse kholo. Liphatsa tse ling tsa lefutso tse hatellang hlahala li ka khutsisoa ka lebaka la hypermethylation ea promoter, e leng se sitisang lisele mekhoa ea taolo ea kholo. Ka lehlakoreng le leng, libaka tse ling tsa genome li ka fetoha hypomethylated, e leng se lebisang ho se tsitse ha chromosome.
Ntle le kankere, ho senyeha ha epigenetic ho boetse ho amana le mafu a methapo a kang Alzheimer's le Parkinson's, mathata a metabolism a kang lefu la tsoekere la mofuta oa 2, le mafu a autoimmune. Esita le mathata a mang a nts'etsopele a kang Prader-Willi le Angelman syndromes a amana le epigenetic genomic imprinting.
Epigenetics e le Sepheo sa Kalafo
Hobane liphetoho tsa epigenetic li ka fetoloa, ke sepheo se khahlang bakeng sa nts'etsopele ea meriana. Mekhoa e 'maloa ea phekolo ea kankere e se e ntse e sebelisa li-inhibitor tsa li-enzyme tse amehang ho methylation ea DNA kapa histone deacetylation, joalo ka li-inhibitor tsa DNMT le li-inhibitor tsa HDAC. Meriana ena e ka tsosolosa tlhahiso ea liphatsa tsa lefutso tse khutsitseng, ho kenyeletsoa le liphatsa tsa lefutso tse hatellang hlahala.
Leha ho le jwalo, phekolo ya epigenetic e hlahisa diphephetso hobane diphetoho tsa epigenetic di ka etsahala diphatseng tse ngata tsa lefutso ka nako e le nngwe. Maano a nepahetseng haholoanyane a hlokahala ho fihlella ditlamorao tse rerilweng le ho fokotsa ditlamorao. Ntshetsopele ya mahlale a kang ho hlophisa epigenome ho thehilweng ho CRISPR le yona e qala ho bula menyetla ya ho fetola matshwao a epigenetic dibakeng tse itseng tsa lefutso ntle le ho kgaola DNA.
Epigenetics Lefa
Potso e 'ngoe e thahasellisang ke hore na liphetoho tsa epigenetic li ka futsoa. Libopuoeng tse ling, matšoao a itseng a epigenetic a ka tsoela pele ho pholletsa le meloko. Ho batho, matšoao a mangata a epigenetic a "busetsoa bocha" nakong ea ho thehoa ha gamete le nts'etsopele ea pele ea lesea le sa tsoa emoloa. Leha ho le joalo, ho na le matšoao a hore liphetoho tse itseng li ka futsoa ka mekhoa e rarahaneng, leha sena e ntse e le sebaka se mafolofolo sa lipatlisiso.
Qetello
Epigenetics ke karolo ea bohlokoa taolong ea liphatsa tsa lefutso hobane e khetholla phihlello ea DNA le maemo a tlhahiso ea liphatsa tsa lefutso ntle le ho fetola tatellano ea liphatsa tsa lefutso. Ka methylation ea DNA, liphetoho tsa histone, le RNA e sa ngoleng khoutu, lisele li ka laola ts'ebetso ea liphatsa tsa lefutso ka matla ho latela litlhoko tsa nts'etsopele le likarabelo tsa tikoloho. Ho utloisisa epigenetics ho thusa ho hlalosa phapang ea lisele, tšusumetso ea mokhoa oa bophelo bophelong bo botle, le tšimoloho ea mafu a fapaneng. Ho feta moo, epigenetics e fana ka menyetla e meholo bongakang, haholo-holo ka lebaka la tlhaho ea eona e ka fetoloang. Ka lipatlisiso tse tsoelang pele, epigenetics e na le monyetla oa ho ba motheo oa bohlokoa bakeng sa mekhoa ea phekolo e nepahetseng haholoanyane le e ikhethileng nakong e tlang.
