Mid ka mid ah faraqa ugu da'da weyn ee hidde-yaqaannada ee u dhexeeya bini'aadamka iyo chimpanzees ayaa laga yaabaa inay caawiyeen hominids qadiimiga ah, iyo hadda bini'aadamka casriga ah, waxay ku guulaystaan masaafo dheer. Si loo fahmo sida isbeddelku u shaqeeyo, saynisyahannadu waxay baareen murqaha jiirarka ee hidde ahaan wax laga beddelay si loo qaado isbeddelka. Jiirka leh isbeddelka, heerarka ogsajiinta ayaa kordhay ilaa murqaha shaqada, kordhinta dulqaadka iyo yaraynta daalka guud ee muruqa. Cilmi-baarayaashu waxay soo jeedinayaan in isbeddelku uu si la mid ah ugu shaqeyn karo bini'aadamka.
Qaar badan oo la qabsiga jireed ayaa ka caawiyay inay bini'aadamku ku sii xoogaystaan orodka fogaanta: kobcinta lugaha dhaadheer, awoodda dhididka, iyo luminta dhogorta ayaa dhammaantood gacan ka geystay kor u kaca dulqaadka. Cilmi-baadhayaashu waxay rumaysan yihiin in ay "heleen aasaaska molecular ee ugu horreeya isbeddelladan aan caadiga ahayn ee bini'aadamka," ayuu yidhi cilmi-baadhaha caafimaadka iyo qoraaga hormuudka ah Ajit Warki.
Hidde-sidaha CMP-Neu5 Ac Hydroxylase (CMAH ee gaaban) ayaa ku beddelmay awoowayaasheen qiyaastii laba ama saddex milyan oo sano ka hor markii hominids ay bilaabeen inay ka baxaan kaynta si ay u quudiyaan oo uga ugaarsadaan savannah ballaaran. Tani waa mid ka mid ah farqiga ugu horreeya ee hidde-sidaha ee aan ka naqaanno bini'aadamka casriga ah iyo chimpanzees. 20-kii sano ee la soo dhaafay, Varki iyo kooxdiisa cilmi-baarista waxay aqoonsadeen hiddo-sideyaal badan oo la xiriira orodka. Laakin CMAH waa hiddo-wadaha ugu horreeya ee tilmaamaya hawl la soo saaray iyo karti cusub.
Si kastaba ha ahaatee, dhammaan cilmi-baarayaashu kuma qanacsana doorka hidda-socodka ee horumarka aadanaha. Bayooloji Ted Garland, oo ku takhasusay physiology evolutionary at UC Riverside, ayaa ka digay in xiriirku wali yahay "malo-awaal saafi ah" marxaladan.
"Aad ayaan uga shakisanahay dhinaca bini'aadamka, laakiin shaki iigama jiro inay wax u qabato murqaha," ayuu yidhi Garland.
Bayoolajigu waxa uu rumaysan yahay in si fudud u eegida wakhtiga isku xigxiga markii uu isbeddelkani kacay aanay ku filnayn in la yidhaahdo in hidde-sidahan gaarka ahi uu door muhiim ah ka qaatay horumarka orodka.
Isbeddelka CMAH wuxuu u shaqeeyaa isagoo beddelaya dusha sare ee unugyada ka kooban jidhka bini'aadamka.
"Qof kasta oo jidhka ka mid ah waxa uu si buuxda ugu daboolan yahay kayn wayn oo sonkor ah," ayuu yidhi Varki.
CMAH waxay saamaysaa dushan iyada oo deddejinaysa sialic acid. Isbeddelkan dartiis, aadanuhu waxay leeyihiin hal nooc oo sialic acid kaynta sonkorta ee unugyadooda. Naaslay kale oo badan, oo ay ku jiraan chimpanzees, waxay leeyihiin laba nooc oo aysiidh ah. Daraasadani waxay soo jeedinaysaa in isbeddelka asiidhka ee dusha sare ee unugyada uu saameeyo habka ogsijiinta loo geeyo unugyada muruqa ee jirka.
Garland waxay u malaynaysaa inaynaan u qaadan karin in isbeddelkan gaarka ahi uu muhiim u yahay bini'aadamka si ay ugu koraan orodyahannada fogaanta. Fikraddiisa, xitaa haddii isbeddelkan uusan dhicin, isbeddello kale ayaa dhacay. Si loo caddeeyo xidhiidhka ka dhexeeya CMAH iyo horumarka aadanaha, cilmi-baarayaashu waxay u baahan yihiin inay eegaan adkaanta xayawaanka kale. Fahamka sida uu jidhkeenu ugu xidhan yahay jimicsiga kaliya kama caawin karto ka jawaabista su'aalaha ku saabsan wixii hore, laakiin sidoo kale in la helo habab cusub oo lagu wanaajiyo caafimaadkeena mustaqbalka. Cudurro badan, sida sonkorowga iyo wadne xanuunka, ayaa lagaga hortagi karaa jimicsiga.
Si aad u ilaaliso wadnahaaga iyo xididdada dhiiggaaga inay shaqeeyaan, Ururka Wadnaha ee Maraykanku wuxuu ku talinayaa 30 daqiiqo oo dhaqdhaqaaq dhexdhexaad ah maalin kasta. Laakiin haddii aad dareento dhiirigelin oo aad rabto in aad tijaabiso xadkaaga jireed, ogow bayolojigu waa dhinacaaga.