DNA

DNA (Deoxyribonucleic Acid) wasu sinadaran ƙwayoyin halitta ne masu ɗauke da cikakken bayanan da ke tsara yadda jikin ɗan Adam da na sauran halittu zai kasance, Wannan tsari ya haɗa da ƙirƙirar sassan jiki, kalar fata, jini, gashi, da ma yadda jikin zai riƙa aiwatar da ayyukansa. Sannan DNA ne ginshiƙin gadon siffofin halitta (genetic material) a kusan dukkan halittu da suka haɗa da mutane, dabbobi, tsirrai, da yawancin ƙwayoyin cuta. Ana samun DNA ne a cikin ƙwayar halitta (cell nucleus), inda ake kiran shi da nuclear DNA, sannan kuma wasu ’yan kaɗan suna cikin (mitochondria), wato hanyar samar da kuzari na kwayoyin halitta, wadda a kimiyyance ake kiran shi da mitochondrial DNA.

Tarihin gano ilimin DNA

Ilimin DNA na da daɗaɗɗen tarihi tun fiye da shekaru ɗari, wanda masana kimiyya suka daɗe da fara rubuce-rubuce a kai.

• Friedrich Miescher (1869): Bature ne ɗan ƙasar Switzerland da ya fara gano wani sinadari a cikin ƙwayoyin jini na white blood cells wanda ya kira nuclein, daga nan aka fara fahimtar mene ne DNA.
• Phoebus Levene (1910): Ya gano cewa DNA yana ƙunshe da phosphate, sugar (deoxyribose) da bases. Inda ya samar da tushen fahimtar tsarin DNA.
• Rosalind Franklin da Maurice Wilkins (1952): Rosalind Franklin ta yi amfani da X-ray diffraction ta ɗauki hoton da ya nuna siffar DNA a matsayin X, wanda ya ba da muhimmiyar shaida kan tsarin helix.
• Watson and Crick (1953): James Watson da Francis Crick ne suka fito da cikakken tsarin double helix, kuma wannan ne ya buɗe kofar kimiyya ta zamani a fannin ilimin halitta.

Siffofin DNA

DNA yana da tsari na musamman da ake kira double helix, wato kamar igiyoyi biyu da suka nannade juna tare da samar da fuskoki masu siffar matattakala, sannan DNA ya ƙunshi tsari guda uku da suka haɗa da:

Phosphate group: Su ne ƙananun ƙwayoyin sinadaran da ke ɗauke da phosphorus da oxygen. A DNA, wannan su ne ke ba da ƙarfin garkuwa (backbone) wato ginshiƙan gefe guda biyu.

Sannan yana haɗa sugar ɗin kowane ɓangare ta hanyar phosphodiester bonds. Yana ba da kariya mai ƙarfi wadda ke kare DNA daga lalacewa. Yana ƙarfafa tsarin “double helix” wato siffar matattakalar da ta nannaɗe kamar igiyar tsani. Wadda take ba da damar adana bayanai masu yawa a cikin ƙaramin wuri.

Sugar-Phosphate Backbone: Wannan shi ne garkuwa ko benaye na DNA, wanda ke riƙe igiyoyin gefe biyu.

Sugar (Deoxyribose): shi kuma ana masa laƙabi da sukarin carbon biyar (5-carbon sugar) da ke cikin DNA. An kira shi “deoxy” saboda yana da reshe ɗaya na oxygen idan aka kwatanta da ribose na RNA.

Yana ɗaure nitrogenous base wato haruffan DNA (A, T, C ko G). Yana haɗuwa da phosphate group a sama da ƙasa don samar da sarƙar DNA. Shi ne ke bambanta DNA da RNA, domin RNA yana da ribose, DNA yana da deoxyribose.

Nitrogenous Bases: Nitrogenous bases su ne haruffan halitta da DNA ke amfani da su wajen rubuta bayanan gado. Kamar haruffan da ake rubuta kalmomi. Waɗannan haruffa na DNA su ne (A, T, C, G)

• Adenine (A): Nau’in purine ne (Sinadaran da ke taimakawa DNA), wanda ke da girma fiye da pyrimidine. Yana haɗuwa da Thymine (T) kaɗai ta hanyar two hydrogen bonds. Yana da muhimmanci wajen rubuta bayanai. Yana shigar da rubuce-rubucen bayanan da DNA ya ƙunsa, sannan ya kuma bada tsari wajen rarraba saƙon a cikin genetic code.
• Thymine (T): Nau’in pyrimidine (Sinadaran da ke taimakawa sikarin DNA), Yana haɗuwa da Adenine (A) ta hydrogen bonds biyu. Ana samun Thymine a DNA kawai, ba a RNA (Rebounucleic Acid) ba. Yana taimaka wa DNA ya kasance mai ƙarfi da daidaito. Yana hana kuskure lokacin da ake ƙirƙirar kwafi na siffofin gado
• Cytosine (C): Nau’in pyrimidine ne. Yana haɗuwa da Guanine (G) ta hanyar three hydrogen bonds, wanda ya fi ƙarfi fiye da A-T. Yana da alaƙa wajen daidaituwar double helix. Sannan yana taimaka wa Enzymes wurin kwafar bayanan DNA da gaggawa.
•  Guanine (G): Nau’in purine kamar Adenine. Yana haɗuwa da Cytosine (C) ta three hydrogen bonds. Yana ƙara ƙarfi da juriya ga DNA saboda haɗin G-C yana da ƙarfi. Yana taka rawa wajen nazarin bambance-bambance tsakanin halittu.

A taƙaice yadda haruffan DNA ke haɗuwa:

• ADENINE yana haɗuwa da THYMINE
• CYTOSINE yana haɗuwa da GUANINE

Wannan ne cikakken haɗin da ke samar da ayyukan DNA cikin tsari ba tare da samun matsala ba, idan kuwa har aka samu matsala, to DNA ba zai yi aikinsa ba.

Yadda DNA ke aiki

• Transcription: Wannan shi ne lokacin da DNA yake ba da umarni a rubuta saƙonsa cikin RNA (Ƙwayar sinadarin da ke taimakawa DNA wurin aika saƙo da gina jiki).
• Translation: RNA zai kai wannan saƙo zuwa ribosome, inda ake fassara bayanin zuwa protein, waɗanda suke gina jiki da aiwatar da dukkan ayyukan sel.
• Regulation of genes: DNA ba kawai umarni yake bayarwa ba; yana kuma tsara lokacin da ake buƙatar wasu sinadarai kamar jin yunwa, jiki zai buɗe genes don samar da glucose. Idan kuma jiki ya kamu da ciwo, DNA zai kunna genes masu samar da antibodies.

Muhimmancin DNA

A fannin rayuwa, DNA na matuƙar taka rawar gani cikin aikace-aikacensa da suka haɗa da:

• Gado (Heredity): DNA ne ke tabbatar da cewa siffofi da halayen ƴaƴa kamar launin fata, tsawo, launin ido, da wasu dabi’un sun yi daidai dana iya iyayensu. Ma’ana Ɗa ya biyo siffofin mahaifansa, ta yadda da an kalle shi za a gane ɗansu ne.
•  Gina jiki: DNA ne ke ɗauke da bayanan da ke sarrafawa tare da samar da proteins na ginin jiki da dukkan hormones, enzymes, da sauran muhimman sinadaran da ke bunƙasa jiki.
• Kula da tsarin jiki: DNA na tabbatar da cewa ƙwayoyin halitta sun san aikinsu na rarrabuwa, girma, mutuwa, tare da samar da sabbi a daidai lokacin da ya dace.
•  Gano mutane (DNA Fingerprinting): Ana amfani da DNA wajen binciken iyaye da ’ya’ya, binciken manyan laifuka, gano gawawwaki, da tantance mutanen da aka rasa.

Nau’ukan DNA

• Nuclear DNA: Shi ke cikin nucleus. Yana da rumbun adana bayanan halitta (chromosomes) 46 a jikin mutum.
• Mitochondrial DNA: Ana samunsa a mitochondria, kuma uwa ce kawai ke samar da shi. Ana amfani da shi wajen binciken tarihin zuriyoyi.
• Circular DNA: Ana samun irin wannan a cikin ƙwayoyin cuta (bacteria) da mitochondria.
• Viral DNA: Wasu ƙwayoyin cuta suna da DNA maimakon RNA.

Canje-canjen da ka iya samun DNA

DNA na iya samun canje-canje (Mutation) idan wani abu ya faru a tsarin bases ɗin DNA, daga cikin chanje-chanjen akwai:

• Point mutation: canji a wuri guda.
• Insertion: ƙarin samun matattalar DNA (Base)
• Deletion: A samu raguwar base.
• Duplication: an ninka wani yanki na DNA.
• Frameshift mutation: canjin da ya rikitar da matattakalar (base) gaba ɗaya.

Abubuwan da ke jawo canje-canjen a DNA

• Radiation (kamar hasken x-ray mai yawa), Taba sigari, Guba, Kuskure yayin replication, Kwayoyin cuta (viruses)

 Sakamakon da canje-canjen da DNA ke haifarwa

Canje-canjen DNA zai iya zama wani lokaci zai iya zama mara illa, wani lokaci kuma jawo cututtuka kamar sickle cell anemia, cancer, cystic fibrosis da sauransu.

Yawaitar DNA a cikin ƙwayar halitta

Kafin cell ya rabu, DNA yana ninkawa ta hanyar fitar da kwafi-kwafinsa. Wannan tsari yana tabbatar da cewa kowane sabon sel ya samu cikakken adadin bayanan halitta kamar yadda tsohon sel ya mallaka.

Rarrabuwar DNA da ƙwayoyin halitta

DNA yana tattare a cikin ƙananan sassan gado da ake kira genes, waɗanda ke ɗauke da bayanin gina sinadaran jiki. Genes ɗin suna a jere a kan chromosomes, waɗanda suke cikin nucleus. Kowane mutum yana da chromosomes 46 gaba ɗaya, inda yake samun 23 daga ɓangaren uwa, 23 daga ɓangaren uba.

Muhimmancin DNA a ilimi da kimiyya

A fannin lafiya da kimiyya ana amfani da DNA don gano cututtuka tun kafin haihuwa, tare da gano cututtuka masu alaƙa da gado. Sannan yana taimakawa wajen samar da magunguna da allurai. Yana taimako wajen nazarin tarihin halittu. Sannan ana amfani da shi wajen aikin gona don samar da tsirrai masu inganci. Har ila yau, DNA na taimakawa wajen binciken genes masu jawo ciwon zuciya, sankara, da diabetes.

A fannin magunguna ma yana taimakawa wajen samar da magunguna na musamman ga mutum (personalized medicine)

A bangaren aikin gona, ana canza DNA domin samar da irin tsirrai masu Juriyar ƙwari, yawaitar amfanin gona, da kuma girma cikin sauri da inganta sinadarai. Sannan ana sarrafa DNA ta hanyar haɗa na’ukan tsirrai daban-daban.

Manazarta

Sulaiman, H. (2025, November 24). Genetics | Bakandamiya. Bakandamiya.

Seladi-Schulman, J., PhD. (2022, February 11). DNA explained and explored. Healthline.

Deoxyribonucleic acid (DNA). (n.d.-d). Genome.gov.

Definition: DNA. (n.d.). Nemours KidsHealth.

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