Tsarin DNA ko Marufi a cikin Kwayoyin Halitta
A matakin kwayoyin halitta, rayuwa a Duniya an gina ta ne bisa tushen bayanan kwayoyin halitta da ke cikin kwayoyin halittar DNA. DNA, ko deoxyribonucleic acid, wani sinadari ne da ke adana umarnin halittu masu mahimmanci don ci gaba, aiki, girma, da kuma haifuwar dukkan halittu masu rai. Kodayake DNA ta ƙunshi nau'ikan nucleotides guda huɗu kawai - adenine (A), thymine (T), cytosine (C), da guanine (G) - tsarinsu a cikin ƙwayoyin halitta yana da matuƙar rikitarwa. Bari mu bincika dalla-dalla yadda ake tsara DNA, ko kuma a naɗe ta, a cikin ƙwayoyin halitta.
Tsarin Asali na DNA
DNA yana da siffar helix guda biyu, wanda James Watson da Francis Crick suka gano a shekarar 1953. Wannan tsari yayi kama da tsani mai karkacewa, tare da ma'auratan tushe a matsayin madauri da kuma kashin baya na sukari-phosphate a matsayin madauri. Ma'auratan tushe tsakanin adenine da thymine, da cytosine da guanine, an haɗa su ta hanyar haɗin hydrogen, wanda ke samar da kwanciyar hankali ga helix guda biyu.
Histones da Nucleosomes
A cikin ƙwayar halittar eukaryotic, ƙwayar halittar DNA na iya zama mita da yawa idan aka miƙe gaba ɗaya. Sanya wannan babban ƙwayar halittar a cikin ƙwayar halittar da ke auna 'yan micrometers kaɗan a diamita yana buƙatar ingantaccen tsarin marufi. Ɗaya daga cikin mahimman abubuwan da ke cikin marufin DNA shine sunadaran da ake kira histones.
Histones sunadaran asali ne masu wadataccen amino acid lysine da arginine, wanda ke ba su damar yin mu'amala yadda ya kamata da DNA mai acidic. DNA yana naɗe a kusa da histones, yana samar da sifofi da aka sani da nucleosomes. Kowace nucleosome ta ƙunshi kusan nau'i-nau'i 147 na tushe na DNA da aka naɗe a kusa da ƙungiyar histones guda takwas, suna samar da sashin marufi na asali na chromatin. Wannan sarkar nucleosomes tana kama da "zaren beads" a ƙarƙashin na'urar hangen nesa.
Chromatin da Kwayoyin Halitta
Marufin DNA yana ci gaba ta matakai mafi girma, inda aka tsara nucleosomes zuwa wani tsari mai ƙanƙanta da tsari wanda ake kira chromatin. Akwai manyan nau'ikan chromatin guda biyu: euchromatin da heterochromatin. Euchromatin shine siffa mafi buɗewa da aiki ta hanyar rubutu, ma'ana DNA a waɗannan yankuna ya fi sauƙin samu ga injinan rubutu. Sabanin haka, heterochromatin ya fi ƙanƙanta kuma galibi yana da alaƙa da DNA mara aiki ta hanyar rubutu.
Ƙarin tsari yana samar da ƙwayoyin halittar chromosomes, mafi girman tsarin marufi na DNA, wanda ake iya gani a lokacin rabuwar ƙwayoyin halitta. Kwayoyin halittar chromosomes sune mafi ƙarancin nau'in DNA kuma suna tabbatar da daidaiton kwafi na DNA ba tare da rasa muhimman sassa ba yayin mitosis da meiosis. Misali, mutane suna da ƙwayoyin halittar chromosomes 46 a cikin kowace ƙwayar halitta ta jiki.
Dokokin Marufi na DNA
Marufin DNA ba tsari ne mai tsauri ba; yana da ƙarfi kuma yana da tasiri daga abubuwa daban-daban. Gyaran Histone, kamar acetylation, methylation, phosphorylation, da ubiquitination, na iya canza hulɗar da ke tsakanin DNA da histones, ta haka yana shafar yawan chromatin da kuma damar DNA don fassarawa. Misali, acetylation na histone yawanci yana da alaƙa da euchromatin da rubutun aiki, yayin da methylation na iya taka rawa wajen samar da heterochromatin.
Baya ga histones, akwai kuma sunadaran sake fasalin chromatin waɗanda zasu iya motsawa, ragewa, ko sake tsara matsayin nucleosome, wanda ke ƙara daidaita damar samun kwayoyin halitta. Duk waɗannan abubuwan suna aiki tare don inganta tsarin DNA don biyan buƙatun ƙwayoyin halitta masu canzawa.
Kunshin DNA a cikin Prokaryotes
Ba kamar ƙwayoyin cuta na eukaryotes ba, ƙwayoyin cuta da sauran ƙwayoyin cuta na prokaryotic galibi suna da DNA mai zagaye, maimakon layi, kuma ba su da ƙwayar da ke ɗaure da membrane. Ko da yake sun fi sauƙi, marufin DNA a cikin prokaryotes ba shi da wani muhimmanci. A cikin ƙwayoyin cuta, DNA yana taruwa da taimakon sunadarai kamar HU da IHF, waɗanda ke daidaita supercoiling kuma suna daidaita tsarin nucleoid.
Muhimmancin Marufin DNA
Ingantaccen marufin DNA ba wai kawai yana game da adana bayanan kwayoyin halitta ba ne, har ma yana game da daidaita aikin kwayar halitta. Matsayi da yawan chromatin na iya yin tasiri ga bayyanar kwayar halitta, kuma, saboda haka, shine abin da bincike da yawa a cikin epigenetics suka mayar da hankali a kai. Nazarin samfuran epigenetic na iya samar da fahimta game da yanayi da cututtuka iri-iri na lafiya, gami da ciwon daji da matsalolin ci gaba.
Misali, canje-canje a cikin tsarin marufi na DNA na iya haifar da rashin daidaituwar bayyanar kwayoyin halitta, wanda ke da alaƙa da ci gaban cutar kansa. Magungunan da ke mai da hankali kan gyare-gyaren histone ko tsarin chromatin suna nuna yuwuwar magance cututtukan da ke haifar da rashin daidaituwar tsarin epigenetic.
Kammalawa
Tsarin ko marufi na DNA a cikin ƙwayoyin halitta tsari ne mai rikitarwa da cikakken bayani wanda ke taka muhimmiyar rawa a rayuwa. Marufi na DNA ba wai kawai yana tasiri ga kwanciyar hankali na kwayoyin halitta ba yayin rabuwar ƙwayoyin halitta, har ma yana aiki a matsayin babban mai kula da su, yana tsara waɗanne kwayoyin halitta ne ake bayyanawa a daidai lokacin da kuma a daidai adadin. Fahimtar cikakkun bayanai game da marufi na DNA yana ba da zurfin fahimta game da tushen ilimin halittar ƙwayoyin halitta kuma yana share hanyar haɓaka sabbin hanyoyin magance cututtukan kwayoyin halitta da na epigenetic. A matsayin ɗaya daga cikin asirai mafi ban sha'awa a fannin ilmin halittar ƙwayoyin halitta, bincike a wannan fanni zai ci gaba da bayar da ƙalubale da damammaki masu ban sha'awa ga masana kimiyya a duk duniya.
