Soma ibirimo

Reba urutonde rw'ibirimo

 IKIBAZO CYA 1

Ubuzima bwabayeho bute?

Ubuzima bwabayeho bute?

Ese ukiri umwana wigeze ubaza ababyeyi bawe uti: “Umwana aturuka he?” None se bagushubije iki? Bitewe n’imyaka wari ufite cyangwa imico y’ababyeyi bawe, bashobora kuba barakwihoreye cyangwa bakaguha igisubizo kidafashije. Cyangwa bashobora kuba barakubwiye ibintu, wamara gukura ugasanga ari ibinyoma. Birumvikana ko iyo umuntu amaze kuba mukuru, aba agomba gusobanukirwa ibintu bitangaje bibaho kugira ngo abantu bororoke.

Nk’uko hari ababyeyi benshi bagira isoni zo kubwira abana babo aho umwana aturuka, hari abahanga badashaka kuvuga ku kibazo k’ingenzi kurushaho kigira kiti: “Ubuzima bwakomotse he?” Nyamara iyo umuntu abonye igisubizo gikwiriye k’icyo kibazo, bishobora gutuma ahindura ukuntu yabonaga ubuzima bwe n’agaciro aha ubuzima muri rusange. None se ubuzima bwakomotse he?

Intanga ngore n’intanga ngabo by’umuntu byamaze guhura bigakora igi, ryatubuwe inshuro zigera kuri 800

Icyo abahanga benshi babivugaho. Abantu benshi bemera ubwihindurize bavuga ko ubuzima bwatangiye kera cyane mu myaka ibarirwa muri za miriyari, butangiriye mu kizenga cyari hafi y’inyanja cyangwa hasi mu nyanja. Bavuga ko utuntu two mu rwego rwa shimi twari aho ngaho, twiteranyije tukavamo utuntu tumeze nk’urufuro. Utwo tuntu tumeze nk’urufuro na two twariteranyije tuvamo icyo bita morekire. Izo morekire zihambaye na zo zatangiye kugenda zororoka zivamo izindi nyinshi. Bavuga ko ubuzima bwose bwo ku isi bwabayeho mu buryo bw’impanuka, buhereye kuri izo morekire, ari zo ngirabuzimafatizo “zoroheje.”

Icyakora hari abandi bahanga bakomeye batemera icyo gitekerezo nubwo bemera ubwihindurize. Bakeka ko ingirabuzimafatizo za mbere cyangwa ibice by’ingenzi byazo, byageze ku isi biturutse mu kirere. None se kuki babyemera batyo? Ni ukubera ko abahanga bananiwe kwemeza ko ubuzima bushobora guturuka ku bintu bidafite ubuzima nubwo bakoze ubushakashatsi bwinshi. Mu mwaka wa 2008,  umwarimu wo muri kaminuza wigisha ibinyabuzima witwa Alexandre Meinesz yavuze ko mu myaka irenga 50 ishize, “nta kimenyetso gifatika abahanga bari babona kigaragaza ko ubuzima bwabayeho ku isi mu buryo bw’impanuka, buhereye ku rusukume rwa za morekire, kandi nta n’ubushakashatsi bwakozwe bugaragaza ko ibyo bishoboka.”1

Ibimenyetso bigaragaza iki? Ubu aho umwana aturuka harazwi neza kandi ntawuhashidikanyaho. Buri gihe ubuzima buturuka ku bundi buzima bwari busanzweho. Ariko se dusubiye inyuma kera cyane, haba hari igihe bitari bimeze bityo? Ese ubuzima bwaba bwarabayeho mu buryo bw’impanuka, buturutse ku bintu byo mu rwego rwa shimi bitagira ubuzima? Amahirwe y’uko ibyo byashoboka yaba angana iki?

Abashakashatsi babonye ko kugira ngo ingirabuzimafatizo ibeho, bisaba ko nibura morekire z’amoko atatu zihambaye zikorera hamwe. Izo morekire ni ADN, ARN na poroteyine. Muri iki gihe abahanga bake ni bo bemeza ko ingirabuzimafatizo yuzuye yabayeho mu buryo bw’impanuka, iturutse ku bintu byo mu rwego rwa shimi bitagira ubuzima. None se amahirwe y’uko ARN na poroteyine byabaho mu buryo bw’impanuka angana iki? *

Stanley Miller, 1953

Abahanga benshi bumva ko ubuzima bwabayeho mu buryo bw’impanuka, bitewe n’ubushakashatsi bwakozwe ku nshuro ya mbere mu mwaka wa 1953. Muri uwo mwaka ni bwo Stanley L. Miller yakoze zimwe muri za aside amine zikoreshwa mu gukora za poroteyine. Yafashe uruvange rw’imyuka, batekereza ko rugereranya ikirere k’isi ya kera, maze arushyiramo amashanyarazi. Nyuma yaho hari za aside amine zagiye ziboneka no mu bibuye bihanuka mu kirere bikagwa ku isi. None se ibyo byaba bigaragaza ko ibintu byose bikenewe kugira ngo ubuzima bubeho bishobora kubaho mu buryo bw’impanuka?

Umwarimu wigishaga shimi muri kaminuza y’i New York witwa Robert Shapiro yaravuze ati: “Hari abanditsi bagiye bavuga ko ibintu byose bikenerwa kugira ngo ubuzima bubeho bishobora gukorwa, hakoreshejwe ubushakashatsi nk’ubwo Miller yakoze. Nanone bavuga ko ibyo bintu byabonetse no mu bibuye bihanuka mu kirere, ariko si ko bimeze.”2 *

Reka dusuzume ukuntu ARN iteye. ARN igizwe n’utuntu duto cyane twitwa nikerewotide. Nikerewotide ni morekire y’ubundi bwoko iva muri aside amine, ariko yo irahambaye kurushaho. Shapiro yavuze ko nta nikerewotide zabonetse igihe Miller yakoraga ubushakashatsi akavanga imyuka n’amashanyarazi, kandi nta n’izabonetse mu bibuye bimanuka mu kirere bikagwa ku isi.”3 Nanone yavuze ko amahirwe y’uko ibintu byo mu rwego rwa shimi byakwivanga bigakora morekire ya ARN ishobora kwigabanyamo izindi, “ari make cyane mbese hafi ya ntayo, ku buryo biramutse binabayeho inshuro imwe gusa mu isanzure, byaba ari amahirwe adapfa kubaho.”4

Hakenerwa ARN (1) kugira ngo poroteyine zikorwe, (2) ariko poroteyine na zo zirakenerwa ngo ARN ikorwe. Ese ubwo birashoboka ko byombi byaba byarabayeho mu buryo bw’impanuka? Ribozome (3) zo tuzazisuzuma mu gice cya 2.

None se twavuga iki kuri poroteyine? Poroteyine zishobora kuba zigizwe na aside amine zigera kuri 50 cyangwa zibarirwa mu bihumbi. Izo aside amine ziba zitondetse mu buryo budahindagurika. Muri rusange, poroteyine yo  mu ngirabuzimafatizo yoroheje iba igizwe na aside amine zigera kuri 200. Icyakora muri izo ngirabuzimafatizo zoroheje haba harimo poroteyine z’amoko abarirwa mu bihumbi. Amahirwe y’uko poroteyine imwe gusa, igizwe na aside amine 100 gusa yabaho mu buryo bw’impanuka angana na rimwe ugabanyije miriyari inshuro miriyoni.

Niba gukora morekire zihambaye muri raboratwari bisaba umuntu w’umunyabwenge, wahera he wemeza ko morekire zihambaye kurushaho zo mu ngirabuzimafatizo zapfuye kubaho?

Umushakashatsi witwa Hubert P. Yockey, na we yemera inyigisho y’ubwihindurize, ariko yaravuze ati: “Ntibishoboka ko ubuzima bwabayeho butangiriye kuri poroteyine.”5 Kugira ngo poroteyine zikorwe, haba hakenewe ARN, ariko nanone poroteyine ziba zikenewe kugira ngo ARN ikorwe. None se byagenda bite dusanze poroteyine na morekire za ARN zaragize zitya mu buryo bw’impanuka zigahurira hamwe mu gihe kimwe, nubwo amahirwe yo kugira ngo ibyo bibeho ari hafi ya ntayo? Reka tuvuge ko ibyo byabaho. None se amahirwe y’uko byakorana maze bikabyara ubuzima, na bwo bushobora kubyara ubundi buzima yaba angana iki? Dogiteri Carol Cleland * akaba ari umuhanga mu bijyanye n’ubumenyi bw’ikirere yaravuze ati: “Bisa n’aho amahirwe y’uko ibyo byabaho mu buryo bw’impanuka (ngo poroteyine na ARN byiteranye bikore ubuzima), ari ntayo rwose.” Akomeza agira ati: “Nyamara abashakashatsi benshi basa n’abibwira ko bashoboye gukora ARN ukwazo na poroteyine ukwazo, mu mimerere nk’iyariho kera cyane, ibindi byakwikora maze bikiteranya bikabyara ubuzima.” Naho ku birebana n’inyigisho zo muri iki gihe zisobanura ukuntu ibyo bintu by’ibanze bigize ubuzima byabayeho mu buryo bw’impanuka yaravuze ati: “Nta n’imwe muri izo nyigisho itanga ibisobanuro byumvikana bigaragaza uko ibyo byabayeho.”6

Niba gukora robo itagira ubuzima bisaba umuntu w’umuhanga, byasaba ubuhanga bungana iki kugira ngo hakorwe ingirabuzimafatizo? Ubwo ntitwiriwe tuvuga umuntu!

Kuki gusuzuma ibi bintu bidufitiye akamaro? Tekereza ukuntu abahanga barwana no gusobanura ko ubuzima bwabayeho mu buryo bw’impanuka! Hari aside amine babonye ziboneka no mu ngirabuzimafatizo. Bahereye kuri izo aside amine, bagiye muri raboratwari zabo bakora ubushakashatsi bwitondewe bakoresheje ibikoresho bihambaye, maze bakora izindi morekire zihambaye kurushaho. Bizeye ko amaherezo bazakora ibice byose bikenewe kugira ngo bakore ingirabuzimafatizo imwe yoroheje. Twabagereranya n’umuhanga ufata ibintu bisanzwe biboneka hano ku isi, agakoramo ibyuma, purasitiki, sirikone n’insinga yarangiza agakora robo. Hanyuma agashyiramo porogaramu ituma iyo robo ikora izindi zimeze nka yo. None se uwo muhanga abikoze byaba bigaragaza iki? Byaba bigaragaje ko umuntu w’umunyabwenge ashobora gukora imashini ihambaye.

Mu buryo nk’ubwo, abahanga baramutse bakoze ingirabuzimafatizo, rwose baba bakoze ikintu gihambaye. Ariko se ubwo baba  bagaragaje ko ingirabuzimafatizo ishobora kubaho mu buryo bw’impanuka? Reka da. Ahubwo baba bagaragaje ibinyuranye n’ibyo.

Ubitekerezaho iki? Ibimenyetso abahanga bafite kugeza ubu bigaragaza ko ubuzima bushobora kubaho buturutse gusa ku bundi buzima. Tuvugishije ukuri, kwemera ko n’ingirabuzimafatizo yoroheje ishobora kubaho mu buryo bw’impanuka, ivuye mu bintu byo mu rwego rwa shimi bitagira ubuzima, byasaba ukwizera gukomeye pe!

None se urebye ibimenyetso byose twasuzumye, urumva ubuzima bushobora kubaho mu buryo bw’impanuka? Mbere yo gusubiza icyo kibazo, banza usuzume witonze imiterere y’ingirabuzimafatizo. Ibyo biri butume umenya niba ibyo abahanga bavuga bashaka gusobanura aho ubuzima bwaturutse bifite ishingiro, cyangwa niba ari nka bya binyoma bamwe mu babyeyi babwira abana babo iyo bababajije aho umwana aturuka.

^ par. 8 Amahirwe y’uko ADN yabaho mu buryo bw’impanuka, tuzayasuzuma mu gice cya 3, kigira kiti: “Amabwiriza yaturutse he?

^ par. 10 Porofeseri Shapiro ntiyemera ko ubuzima bwabayeho biturutse ku irema. Atekereza ko ubuzima bwabayeho mu buryo bw’impanuka, ariko bakaba bataramenya neza uko byagenze. Mu mwaka wa 2009, abahanga bo muri kaminuza ya Manchester mu Bwongereza, bavuze ko bakoreye muri raboratwari yabo tumwe mu duce tugize ADN twitwa nikerewotide. Icyakora Shapiro yagize icyo avuga ku byo bakoresheje agira ati: “Ndabona rwose ibyo bitakugeza ku nzira yo gukora ARN.”

^ par. 13 Dogiteri Cleland ntiyemera irema. Atekereza ko ubuzima bwabayeho mu buryo bw’impanuka, nubwo tutarasobanukirwa neza uko byagenze.