HAGU KO DAMA: LOKACIN DA SA'A KE ZAƁAR HANNUN RAYUWA

Ƙwayoyin halitta da yawa suna zuwa da sigogi biyu masu kama da juna kamar a madubi, waɗanda ba za a iya ɗora ɗaya a kan ɗaya daidai ba, kamar hannun hagu da hannun dama. Masana kimiyyar sinadarai suna kiran wannan chirality (siffar hannu), kuma sigogin biyu enantiomers. A cikin halittu masu rai, amino acid da sukari suna bayyana galibi a cikin ɗaya daga cikin siffofin biyu. Yadda wannan rashin daidaito ya samo asali, da kuma dalilin da ya sa aka zaɓi hannu ɗaya, har yanzu ba a fahimta sosai ba.

Wata ra’ayi ita ce ya faru ne da kansa, daga cakuɗin racemic — adadi ɗaya na hannayen biyu — a cikin yanayi mai nisa da daidaiton sinadarai (chemical equilibrium). Gwaje-gwaje sun nuna cewa daidaiton madubi zai iya karkata: a cikin lu’ulu’un sodium chlorate da aka girma ana juyawa, a cikin wani sinadari da ake kira Soai reaction, ko a cikin ƙananan sarƙoƙin amino acid da wani sinadari na kafin rayuwa (prebiotic) ya samar.

Girke-girken Frank na zaɓar gefe

Ka’idar da ta fi tasiri ta samo asali ne tun daga F. C. Frank a 1953. Tana buƙatar abubuwa biyu:

• Autocatalysis: kowace ƙwaya tana taimaka wajen samar da ƙarin ƙwayoyi masu hannu iri ɗaya da ita.
• Gasa: ƙwayar hagu da ta dama sun haɗu kuma sun lalata juna.

Bayan wani iyaka, yanayin 50/50 ya zama marar tsayayye kuma cakuɗin ya karkata zuwa hannu ɗaya. A cikin sigar ƙirar ta gargajiya, wadda take tabbatacciya (deterministic), ko da ɗan rinjaye ƙanƙane a farko yana yanke wanda zai yi nasara, kowane lokaci.

Amma sinadarai na gaske suna faruwa ne sinadari ɗaya bayan ɗaya. Idan ƙwayoyin kaɗan ne — kamar yadda wataƙila ya kasance a muhallin kafin rayuwa — sa’a tana taka rawa. Kwaikwayon kwamfuta na baya sun yi nuni da cewa hannun da ya fara da rinjaye ba koyaushe yake yin nasara ba.

Sanya lambobi a kan sa’a

Leonardo Silva-Dias da Christoph Weber, na Jami’ar Augsburg a Jamus, sun ɗauki wata daidaitacciyar sigar ƙirar Frank (wato Kondepudi–Nelson model) kuma sun fitar da dabarun lissafi (analytical formulas) na tasirin bazuwar sa. Babban sauƙaƙawarsu: jimillar ƙwayoyin chiral tana daidaita da sauri fiye da daidaito tsakanin hagu da dama, don haka matsalar ta ragu zuwa canji ɗaya kawai — rashin daidaiton chiral.

Hoton da ya bayyana shi ne na wani ɗan dutse da ke birgima a cikin wani fili mai kwaruruka biyu — ɗaya ga kowane hannu — da wani tudu a tsakaninsu, wato yanayin 50/50. Bugun bazata yana tura ɗan dutsen nan da can. Sun duba kowace dabara da kwaikwayon kwamfuta na sinadaran, an ɗauki matsakaicin gudu 50,000 ga kowanne.

Tasiri uku na ƙananan lambobi

1. Marasa rinjaye za su iya yin nasara. Yiwuwar ƙarewa a wani hannu yana ƙaruwa a hankali tare da rinjayen farko, daga 0 zuwa 1, yana wuce rabi daidai idan farkon ya daidaita. Kullum akwai damar cewa hannun da ya fi ƙaranci a farko ya mamaye. A cikin ƙananan tsarurruka, wannan damar ta dogara ne kawai kan inda wurin farawa yake tsakanin kwaruruka biyun. A cikin manya, abin da ke da muhimmanci shi ne rinjayen idan aka kwatanta da girman da aka saba na girgizar bazata, wadda ke raguwa yayin da yawan ƙwayoyin ke ƙaruwa.

2. Sa’a tana gaggauta abubuwa. Lokacin da ake buƙata don zaɓar hannu yana ƙaruwa tare da girman tsarin kuma yana raguwa idan rinjayen farko ya ƙaru. Bugun bazata yana taimaka wa ɗan dutsen ya bar ƙwanƙolin tudu da sauri. Ga asalin rayuwa, wannan yana da muhimmanci: idan zaɓin yana buƙatar ci gaba da kwararar makamashi, dole ne wannan kwararar ta daɗe aƙalla tsawon lokacin zaɓin.

3. Zaɓin zai iya juyawa. Idan ana samar da ƙwayoyin da sauri daga albarkatunsu kuma gasa tsakanin hannayen biyu ba ta da ƙarfi, ɗan dutsen zai iya tsallake tudun — cakuɗin ya canza hannu. Tsayin tudun yana ƙaruwa daidai gwargwado da yawan ƙwayoyin, kuma yawan tsallakewar yana faɗuwa ta hanyar exponential tare da wannan tsayi. Don haka juyawar tana ɓacewa yayin da tsarurruka ke girma.

Da ƙwayoyi 1,000 cakuɗin yana canza hannu sau da sau; da 2,500 yana canzawa sau ɗaya; da 5,000 yana tsayawa a wurinsa. — Figure 7, Silva-Dias & Weber (2026), arXiv:2610.13523.

Batun girma

Marubutan sun kammala da cewa girgizar bazata tana taka rawa biyu daban-daban: tana tsara wane hannu za a fara zaɓa da saurin zaɓin, kuma daga baya za ta iya girgiza wannan zaɓin. Bincikensu kuma ya sanya wani sharaɗi ga hasashen asalin rayuwa: dole ne zaɓin ya faru yayin da yanayin da ke nesa da daidaito yake ci gaba.

Aikin ya shafi tsarin sinadari ɗaya ne, a cikin tsarin da aka gauraya sosai ba tare da tsarin wuri ba. Marubutan sun yi nuni da wasu hanyoyi zuwa chirality — misali polymer da ke rabuwa zuwa ɗigo-ɗigo kuma su samar da yanayin liquid crystal — kuma sun ba da shawarar faɗaɗa hanyar zuwa gare su.