Nazarin DNA na dadadden fitilar fitila mara kifi wanda ba shi da muƙamuƙi ya bai wa masanan kimiyyar halittar Rasha damar samun amsar tambayar yadda magabatanmu suka sami hadadden kwakwalwa da kwanyar da ake buƙata.
An gano gano wata kwayar halitta ta musamman, wacce halittarta ta baiwa kakanninmu kwalliya da kwakwalwa, a cikin mujallar Kimiyyar Kimiyya. A cewar Andrei Zaraisky, wanda ke wakiltar Cibiyar nazarin kimiyyar halittu ta Kwalejin Kimiyya ta Rasha, an gano kwayar halittar Anf / Hesx1 a cikin fitilar, wacce ita ce mafi tsufa da ke zaune a kashin baya. Mai yiwuwa, bayyanar wannan kwayar halitta ce ta zama jujjuyawa bayan bayyanar bayyanar kwakwalwa a cikin kashin baya ya zama mai yiwuwa.
Ofaya daga cikin mahimman fasali wanda ya banbanta fauna da kashin baya na dabba da invertebrates shine kasancewar hadadden, ingantaccen kwakwalwa. Dangane da haka, don kare kyawawan laushin jijiyoyin daga lalacewar da za ta iya faruwa, kwalliyar kariya mai ƙarfi ta kafa. Amma yadda wannan harsashi ya bayyana, da abin da ya bayyana a baya - cranium ko kwakwalwa - har yanzu ba a san shi ba kuma har yanzu batun rikici ne.
Da fatan samun amsa ga wannan tambayar, masana kimiyya sun lura da ci gaba, aiki da wanzuwar ƙwayoyin halittar ƙwayoyi da kuma fitila, waɗanda sune kifaye masu dadadden tarihi. A cewar masana kimiyya, wadannan kifin da ba su da muƙamuƙi suna da kamanceceniya da ƙananan vertebrates na farko waɗanda suka rayu a cikin babban teku na Duniya kusan shekaru miliyan 400-450 da suka wuce.
Nazarin aikin kwayoyin halitta a cikin amfanonin fitila, Zaraisky da abokan aikinsa sun sami damar yin karin haske kan halittar halittar kashin baya, wanda, kamar yadda aka sani, mutane suke. Masu binciken yanzu suna tantance ko wadanne kwayoyin halitta ne a cikin DNA na kashin baya da kuma wadanda basa cikin invertebrates.
A cewar masanan kimiyyar halittar kasar Rasha, a shekarar 1992, sun sami damar gano wata kwayar halitta mai ban sha'awa (Xanf) a cikin DNA din halittar kwaron kwado, wanda ya tabbatar da ci gaban gaban amfrayo, gami da fuska da kwakwalwa. Bayan haka an ba da shawarar cewa wannan kwayar halitta ce za ta iya saita ci gaban kwakwalwa da kwanyar mutum da kashin baya. Amma wannan ra'ayi bai sami goyan baya ba, tunda wannan kwayar halittar bata cikin mayuka da kuma fitila - mafi mahimmancin kashin baya.
Amma daga baya an samo wannan kwayar halittar a cikin DNA na kifin da aka ambata, kodayake a dan canza yanayin. Ya ɗauki ƙoƙari sosai don samun damar fitar da Hanf wanda ba shi da rai daga cikin amfrayo kuma ya tabbatar da cewa yana aiki kamar misalinsa a cikin DNA na mutane, kwadi da sauran ƙwayoyin dabbobi.
A karshen wannan, masana kimiyya sun ɗaga tayi na fitilar Arctic lampreys. Bayan haka, sun jira har zuwa lokacin da kawunansu ya fara haɓaka, sannan kuma suka samo tarin kwayoyin RNA daga ciki. Wadannan kwayoyin ana samar dasu ne ta kwayoyin halitta lokacin da suke "karanta" kwayoyin halitta. Sannan wannan tsari ya juya kuma masana kimiyya sun tattara gajerun sassan DNA. A hakikanin gaskiya, su kwafin kwayoyin halitta ne wadanda suke aiki sosai a cikin amfrayo.
Ya zama mafi sauƙin nazarin irin jerin DNA ɗin. Yin nazarin waɗannan jerin ya ba masana kimiyya damar gano nau'ikan nau'ikan nau'ikan kwayar Xanf guda biyar, kowanne ɗayansu yana da umarni na musamman don haɗin furotin. Wadannan nau'ikan guda biyar kusan basu bambanta da wadanda ake samu a jikin kwadi ba a cikin shekarun 90 na nesa.
Aikin wannan kwayar halittar a cikin fitilar ya zama daidai yake da na harajinsa akan DNA din wasu kasusuwa wadanda suka bunkasa. Amma akwai bambanci guda ɗaya: wannan kwayar halittar an haɗa ta cikin aikin sosai daga baya. A sakamakon haka, kwanya da kwanyar fitila kanana ne.
A lokaci guda, kamannin tsarin halittar kwayar halittar fitilar Xanf da kuma “kwayar” kwayar halitta Anf / Hesx1 tana nuna cewa wannan kwayar halittar, wacce ta bayyana kimanin shekaru miliyan 550 da suka gabata, tana tabbatar da wanzuwar kasusuwa sosai. Wataƙila, shi ne ɗayan manyan injunan haɓakar ƙwayoyin dabbobi gabaɗaya kuma musamman mutane.
