Ko ubundi utunyangangingo ndangasano tw’abavandimwe b’impanga ari tumwe neza neza, ni kuki usanga izi mpanga zidakurikira inzira z’ubuzima zimwe? Hari umuhanga mu bya siyansi wamaze imyaka 21 abikoraho ubushakashatsi utekereza ko afite igisubizo cy’icyo kibazo.
Ni mu nkuru dukesha ikinyamakuru The Guardian. Ni inkuru ishingiye ku bushakashatsi bwahawe umutwe ugira uti “Identically Different: Why You Can Change Your Genes bwakozwe na Tim Spector butangazwa na Phoenix.
Umubano wa Barbara Oliver n’impanga ye Christine wabaye amayobera mu binyacumi by’imyaka ishize. Mu bihe by’ubwana bwabo aba bombi bafatwaga na rubanda nk’umuntu umwe ariko urimo babiri: bambaraga kimwe ndetse bakogoshwa kimwe ku buryo basaga kurusha intobo. “Ababyeyi bakoze byose ngo bashimangire uburyo twari duteye kimwe.” Uyu ni Barbara ubivuga.
Gusa mu myaka ya za 60 ubwo Barbara na Christine bageraga mu bihe byabo by’ubwangavu (adolescence), byarahindutse. Aba bana b’abakobwa noneho bashoboraga kuba buri wese yahitamo ubwoko bw’imyambaro bwihariye ndetse ugasanga imyambarire yab itandukanye by’ihabya.
Barbara abisobanura mu magambo ye ati “Njye nambara ingutiya ngufi. Christine we akambara ingutiya n’amakoti birebire. Uretse ibi kandi, ugutandukana mu miterere ndangamuntu yabo (personalities) byatangiye kwigaragaza.
Barbara ati “Christine ni umuntu ugira amakenga akabanza kwitondera cyane ibyo akora mu gihe njye nigirira icyizere cyane kurushaho. Ni ibintu byakomeje kugenda byigaragaza uko imyaka yagendaga.”
“Njye rero ndi umuntu wigirira icyizere gike kandi njya ndwara cyane agahinda gakabije (serious depression). Nta kimenyetso nk’icyo Barbara arangwaho. Dushobora kuba turi impamga nyazo (identical twins cyangwa vraies jumelles) yego ariko turatandukanye cyane mu buryo bwinshi.” Uyu ni Christine ubivuga.
Uku gutandukana kw’imiterere gushobora kumvikana nk’ugutangaje. N’ubundi, nk’impanga nyazo, ubundi iyo abana bavukiye rimwe baba bahuje neza utunyangingo ndangasano. Umwe ni ‘kopi’ y’undi. Barezwe ku buryo butuma imiterere yabo bayihuza bagatera kimwe. Kamere-ni ukuvuga uko bavutse- n’uko barezwe byagatumye ubundi baba abantu bateye kimwe koko. Nyamara Barbara and Christine byarangiye babaye abantu batandukanye cyane.
Icyakora ibi ntibibagira impanga zidasanzwe, nk’uko bivugwa na Professor Tim Spector, ukuriye ishami ry’ubushakashatsi ku mpanga kuri King’s College. Barbarana Christine bari mu bemeye gukorerwaho ubushakashatsi n’itsinda ry’abanyeshuri bo muri iyi kaminuza bateye nk’izindi mpanga za nyazo nyinshi (identical twins).
Mu buryo bumwe, ubundi bateye kimwe cyane cyane rwose, ukurikije uko bagaragara, ni urugero. Gusa mu bundi buryo, baratandukanye bigaragara- kandi ni ibintu bigoye kurushaho gusobanura. Prof. Spector agira ati “[Uko batandukanye] tubibona mu buryo butandukanye. Ni urugero, ubushakashatsi bwacu bwerekanye ko impamvu ari gake zicwa n’indwara imwe. Nyamara baba basangiye byinshi mu bibaranga n’uko bateye, nk’uburebure.”
Ushobora kumva ari iyobera. Kuko impanga nyazo ubundi zihuza utunyangingo ndangasano (genes), zitwitirwa mu nda imwe kandi zikaba mu bwana bumwe. “Impanga nyinshi twakoreyeho ubushakashatsi zize ku mashuri amwe kandi zarabanaga, zikarya ibiryo bimwe nibura kugeza zigize imyaka 18 cyangwa gukomeza,” bivugwa na Spector wakoze ubushakashatsi bwe bwa mbere ku mpanga mu myaka 21 ishize. “Gusa uko ubuzima bwabo bwaje kumera biratandukanye cyane.”
Ibyavuye muri ubu bushakashatsi biteye amatsiko cyane kandi biratuma habaho ubumenyi bushya ku myitwarire y’utunyangingo ndangasano n’uburyo ibidukikije bitugiraho ingaruka. Ni ubumenyi bunashobora gusobanura imizi y’amayobera y’ihindagurika ry’ikiremwamuntu nubwo ubwo Spector yatangiraga inyigo ye intego ye itari ngari kugeza aho.
Mu myaka ya za 1990, yakoraga ubushakashatsi ku mizi n’impamvu z’indwara nk’ishaza ifata amaso ikaba yanatera ubuhumyi ndetse n’iyitwa arthritis ifata aho ingingo zihurira ishobora gutera ubumuga. Muri iki gihe, abaganga ntibemeraga iby’uko izi ndwara zaba zizana ku mibiri yabo uko bagenda basaza. Izi ndwara zari ikintu abantu bagomba kwihanganira bakabana na cyo gusa. Ati “Icyakora, nifuzaga kumenya impamvu izi ndwara zikubita bamwe bakiri bato ntibibe bityo ku bandi.”
Aha rero ni ho ubushakashatsi bwe ku mpanga bwatangiriye. Ugereranije impanga nyazo (identical) n’izitari nyazo (fraternal twins), ndetse n’uburyo ibyiyumvo byabo ku ndwara biri, birashoboka gtandukanya imizi ndangasano y’ibyo baba nyuma ndetse n’uko bamera bitewe n’ibyo banyuramo nyuma.
Aha rero Spector yatangiye gushaka izi mpanga ngo azikorereho ubushakashatsi hanyuma itsinda ribumufashamo arishyira ku bitaro bya St Thomas by’i Londres [soma Londere].
Yakoze ibi mu gihe ubushakashatsi bugezweho ku ihuzasano (modern genetics) bwasohokaga bwisukiranya. Mu bihe bya nyuma by’imyaka ya za 80 na za 90, abashakashatsi- bakoresheje ibikoresho byo mu isomo ry’ibinyabuzima bw’utunyangingo duto bugezweho (modern molecular biology- bari batangiye kuvumbura utunyangingo ndangasano dutera imfu ariko tudakunda kubaho ku ndwara ziherereanywa hagati y’umubyeyi n’umwana nka cystic fibrosis (ifata uruhago rw’inkari), indwara ya Huntington, ndetse n’iyo gutakaza uduce tugize imikaya izwi nka muscular dystrophy.
Byari byitezwe ko ubushakashatsi ku nkomoko y’indwara zogeye ubu nk’iy’umutima na diyabete, nubwo zizanamo utunyangingo twinshi bwagombaga gukurikiraho.
“Abahanga mu bumenyi basesenguraga utunyangingo bakabona isano iri hagati y’itsinda ryatwo n’indwara runaka,” nk’uko Spector abivuga. “Ibihumbi ’inyigo kuri utu tunyangingo byarakozwe gusa inyinshi muri zo (inyigo) ntizari zihuje n’ukuri kuko abashakashatsi batashoboraga cyangwa ngo babe barabwigiyeho babugenzura ngo bifashishe ibyabuvuyemo. Iki cyari igihe cyo kwigaragaza gusa no kwimenyekanisha. Iyo wasohoraga ubushakashatsi ntibwemerwe , ntiwabutangazaga; 90% by’ubushakashatsi bwatangajwe byaje gusanga ko bwari nk’ibishingwe.”
Ubushakashatsi nk’ubu bwari ubwa Spector yakoze ku mpanga. Kimwe mu byo bavumbuye bwerekanaga ko akanyangingo kakira vitamin D ari ko mpamvu rukumbi itera osteoporosis, indwara ikunda gufata abagore bamaze gucura (menopause) igatera amagufwa yabo kuvunika nka kimwe mu bimenyetso byayo.
Bisa n’aho ikosa ku kanyangingo kihindurije ryatumye abantu bashidikanya kuri iyi mimerere. Iyi nkuru yashyizwe ku rupapuro rubanza rw’ikinyamakuru Nature, ubundi bisanzwe ari inzozi za buri muhanga mu bumenyi (scientist), uretse gusa kuri iyi nshuro, nko mu zindi nyinshi, byasanzwe koi bi bitari ukuri. “Byari intangiriro y’ikosa. Muri make twaribeshye dukora ikosa,” ni ko Prof Spector abyemera.
Hanyuma rero hataho umushinga wiswe, Human Genome Project, aho uduce miliyari 3 z’utugirangingo ndangasano (DNA) tugize umuntu twasobanuwe. Urwo rukurikirane rw’ikoranabuhanga no gusubiramo cyane ubushakashatsi byahinduye inyigo y’uguhindagurika kw’imiterere ya muntu ndetse n’ubushakashatsi ku matsinda y’impanga.
“Dufite impanga zigera ku 7.000- bivuga ko dushobora inyabubiri z’abavandimwe zigera ku 3.500- mu bitabo byacu hano. Muri aba, abagera kuri kimwe cya kabiri cyabo, imiterere y’utunyangingo twabo yose yizweho,” ni ko Spector avuga.
Buri mwaka, hari ibikorwa byiriza umunsi aho amatsinda y’impanga akorerwaho ubushakashatsi ku ngingo zitandukanye. Hafatwa ibizamini by’amaraso, hakabarwa ubugari bw’amenyo, hagapimwa imikorere y’ibihaha, amafoto y’ibyuma (x-rays) bifotora mu mubiri agafatwa ndetse hakabaho gu ‘scanna’ umubiri wose ndetse n’ibizamini bisuzuma ubuzima bwo mu mutwe.
Christine, imwe mu muri za mpanga twanzikiyeho iyi nkuru agira ati “Tujya muri ibi bikorwa nka rimwe mu mwaka kandi biba ari ibintu bishimishije. Mpabonera amahirwe yo kumarana igihe kingana gityo n’umuvandimwe wanjye.”
Icyakora ibyashyizwe hanze n’ibi bikorwa by’ubushakashatsi bwa buri mwaka bwakorewe ku mpanga bwatumye abahanga mu by’ubumenyangingo ‘geneticists’ bacanganyikirwa, bagwa mu gihirahiro. Aho gusanga utunyangingo tugera mu 10 cyangwa turenga ari two duhuza imimerere, abashakashatsi basanze ko ibi biri mu bagera mu Magana.
“Ku byerekeye osteoporosis, twatekerezaga ko yaba iterwa n’akanyangingo kamwe gahindagurika, ubu twizera ko ahubwo hari utunyangingo tugera nko muri 500 tubizamo. Bivuga ko iyi ndwara ishobora kwibasira abo mu myaka itandukanye.”
Specer akomeza agira ati “Utu ni utunyangingo tugera kuri 0,1% ku kuba katera ibyago byo kurwara indwara runaka ku muntu umwe ku giti cye. Ikindi, utu tunyangingo, usanga akenshi tugize igice cyo gutandandukana tubona mu bwinshi n’ubukomere bw’indwara muri rubanda. Kikaba ikintu abahanga bazi ku izima missing heritability [ni nko kubura ku byo umubyeyi araga umwana mu mubiri].
Ni ikintu ushobora guhita ubona mu nyigo zakorewe ku mpanga nyazo kuri St Thomas. “Ubu twatangiye kutareba gusa ku byo impanga zihuza ahubwo ku bibatandukanya. Ni impinduka twakoze ku buryo tubona ibintu. Umurimo wacu werekana ko umurage w’imyaka uzapfiraho utarenga 25% [ni ukuvuga kuba kumwe kw’imyaka umubyeyi n’umwana bapfiraho]. Ikindi na none mu buryo bumwe, haba ibyago bigera kuri 30% ko iyo impanga imwe muri 2 za nyazo irwaye umutima indi mugenzi wayo izawurwara, mu gihe imibare yo kurwara rheumatoid arthritis cyangwa ubumuga bw’ingingo igera gusa kuri 15%.”
Ni imibare ishishikaje: abantu bahuje utunyangingo ndetse bagahuza akenshi uko barerwa ariko bakagira ubuzima butandukanye cyane. Impamvu yaba iyihe? Igisubizo nkuko Spector abivuga, cyamujemo mu myaka ikabakaba 10 ishize.
Impamvu z’uku kunyurana zatewe n’impinduka zabaye ku ruhurirane rw’impinduka zigenzura imiterere nyangingo ya muntu (human epigenome), ni byo yabonye.
“Ubundi,” nk’uko Prof. Spector abisobanura, “epigenetics ni uburyo impinduka ziva ku bidukikije cyangwa ibyo tunyuramo zihindura imyitwarire y’utunyangingo ndangasano twacu.” Ati “Ibi bibamo icyitwa methylation, bibaho iyo ikinyabutabire kizwi nka methyl, gitemba imbere mu tunyangingo twacu cyihuza nk’icyibohera kuri ADN yacu.
Iyo bigenze bityo, gishobora guhindura igikorwa cy’akanyangingo kacu, kikakabuza gukora bumwe mu bwoko bw’inyubakamubiri (protein) mu mibiri yacu.”
“Akenshi, ubwoko bwose bw’ibitubaho mu buzima bwacu bishobora icyo bihindura ku kigero cyo guhura kwa ADN na methyl mu mibiri yacu: imirire, indwara, ugusaza, ibinyabutabire mu bidukikije, kunywa itabi, ibiyobyabwenge ndetse n’imiti.
Aha rero, uku guhinduka kuba ku tunyangingo ngirasano twacu gutera itandukaniro ku ndwara zafata abahuje isano. Ubushakashatsi bwa vuba bwakozwe na Spector na bagenzi be aho barebaga ibigero bya methylation [uguhura kwa methyl na AND] mu mpanga nyazo bishimangira iki gitekerezo.
Prof Spector agira ati “Twakoze inyigo ku mpanga nyazo zihanganira bitandukanye uburibwe nuko twerekana ko ko bafite imiterere n’ibigero bitandukanye bya methylation. Ibi kandi twabisanze kuri ‘depression’, diyabete ndetse na kanseri y’ibere.
Kuri buri ngingo ukwayo hano, twasanze hari utunyangingo dukora ku mpanga imwe nyamara dusa n’utwazimye ku yindi mugenzi wayo. Ibi ni byo bituma umwe muri aba rero bazafatwa n’indwara runaka cyangwa ntibafate.
Inzara ikurya ifite ingaruka ku bazagukomokaho mu myaka 50 izaza
Impinduka z’utunyangingo ariko ntabwo ziterwa gusa n’iziterwa n’ibidukikije. Izi ni zo zituma utunyangingo ndangasano zikora uko zikora kandi zishobora kugira ingaruka zishobora kumara ibisekuru cyangwa bitatu mu buryo bukomeye.
Urugero, inyigo ku bana ndetse n’abuzukuru bakomotse ku bagore bahuye n’ikibazo cyo gusonza bikabije no kurya nabi byabayeho mu ntambara ya kabiri y’isi no mu Bushinwa mu myaka ya za 50 zerekanye usanga bakunda kugira urubavu ruto, bafite ibyago biruseho bo kurwara diyabete ndetse no kwibasirwa n’uburwayi bwo mu mutwe. Ibi byitirirwa n’impinduka z’utunyangingo ndangasano.
“Ubundi, ni inzira ziganisha ku gukora impinduka z’igihe gito ku gisekuru (generation) cy’abantu,” ni ko Prof Spector abivuga.
“Inzara iraza igatera ariko ntabwo ako kanya wahita uhindura utunyangingo ndangasano twawe. Gusa impinduka z’utunyangingo zituma ushobora kuzabyara abana babyibushye cyangwa bananutse cyangwa ikindi cyose cyabaho bitewe n’ibyabaye bishya. Izi mpinduka zizabaho mu gihe cy’ibisekuru bibiri cyangwa bitatu, kikaba igihe nibura wakwizera ko impinduka mu bidukikije zizaba zitambutse. Hari n’ubwo ibi bitabaho, birumbikana.”
Ni ba nta kindi kintu kibayeho, igitekerezo cyo guhinduka k’utunyangingo ndangasano gisobanura uguhinduka kw’imyitwarire n’imikorere y’impanga n’indwara kandi kiraza kigahura neza kinasubiza ibyo wakwibazaga nkanjye kuri Christine n’impanga ye Barbara.
“Igitekerezo cy’uko ntandukanye n’impanga yanjye nyayo bishobora kuba byaratewe n’ibyatubayeho mu buzima kirumvikanamo ukuri rwose. Barbara yarongowe mbere yanjye. Impanga nyinshi zizakubwira ko iyo ibyo bibaye, indi mpanga isigara mu gahinda. Nanjye ni ko byangendekeye. Nyuma y’aho naje kurwara kanseri yo mu maraso (leukaemia) kandi naje gusenya urugo rwanjye (divorce). Icyo ni ikintu cyagira inkovu gisigira uwo ari we wese. Gusa n’amahirwe hari uruhare abigiramo.” Aya ni amagambo ya Christine.
Iradukunda Fidele Samson
