Wani sabon binciken DNA da aka gudanar ya kammala cewa kwarangwal ɗin ɗan adam mafi tsufa da aka samu a São Paulo, Brazil, Luzio, ana iya samo shi zuwa asalin mazaunan Amurkawa kusan shekaru 16,000 da suka gabata. Wannan rukunin mutane daga ƙarshe ya haifar da ƴan asalin Tupi na yanzu.
Wannan labarin yana ba da bayani game da bacewar tsofaffin mazauna yankin gabar tekun Brazil waɗanda suka gina sanannen “sambaquis,” waxanda suke da tarin harsashi da kasusuwan kifi da ake amfani da su azaman gidaje, wuraren binnewa, da alamomin iyakokin ƙasa. Masu binciken archaeologists akai-akai suna lakabi waɗannan tudun a matsayin tudun harsashi ko tsakiyar kicin. Binciken ya dogara ne akan mafi girman saiti na bayanan kayan tarihi na kayan tarihi na Brazil.
Andre Menezes Strauss, masanin ilimin kimiya na kayan tarihi MAE-USP kuma jagoran binciken, yayi sharhin cewa masu ginin sambaqui na tekun Atlantika sun kasance mafi yawan jama'a a cikin Amurka ta Kudu kafin mulkin mallaka bayan wayewar Andean. Tsawon shekaru dubbai da shekaru, ana ɗaukarsu 'sarakunan bakin teku', har sai da suka bace ba zato ba tsammani shekaru 2,000 da suka wuce.
Marubutan sun yi nazarin kwayoyin halittar burbushin halittu 34, akalla shekaru 10,000, daga yankuna hudu na gabar tekun Brazil. An ɗauko waɗannan burbushin daga wurare takwas: Cabeçuda, Capelinha, Cubatao, Limao, Jabuticabeira II, Palmeiras Xingu, Pedra do Alexandre, da Vau Una, waɗanda suka haɗa da sambaquis.
Levy Figuti, farfesa a MAE-USP, ya jagoranta, ƙungiyar ta gano kwarangwal mafi tsufa a Sao Paulo, Luzio, a cikin kogin Capelinha na tsakiyar kwarin Ribeira de Iguape. Kwankinsa ya yi kama da Luzia, burbushin halittu mafi tsufa da aka samu a Kudancin Amirka zuwa yanzu, wanda aka kiyasta ya kai kimanin shekaru 13,000. Da farko dai masu binciken sun yi hasashen cewa ya fito ne daga wata al'umma daban da na Amerindians na yanzu, wadanda suka mamaye Brazil kimanin shekaru 14,000 da suka wuce, amma daga baya aka tabbatar da cewa karya ce.
Sakamakon binciken kwayoyin halitta na Luzio ya tabbatar da cewa shi dan Amerindia ne, kamar Tupi, Quechua, ko Cherokee. Wannan ba ya nufin cewa sun yi kama da juna, duk da haka ta fuskar duniya, dukkansu sun samo asali ne daga ƙaura guda ɗaya da ta kai nahiyar Amirka fiye da shekaru 16,000 da suka wuce. Strauss ya bayyana cewa idan akwai wata al'umma a yankin shekaru 30,000 da suka wuce, ba ta bar zuriya a cikin wadannan kungiyoyin ba.
DNA na Luzio ya ba da haske ga wata tambaya. Middens na kogin ba su da kama da na bakin teku, don haka ba za a iya ɗaukan binciken ya kasance farkon babban sambaquis na gargajiya da ya bayyana daga baya ba. Wannan wahayin ya nuna cewa an yi ƙaura dabam-dabam guda biyu - zuwa cikin ƙasa da gefen teku.
Menene ya zama na masu yin sambaqui? Binciken bayanan kwayoyin halitta ya nuna bambancin al'ummomi masu kama da al'adu daban-daban amma bambance-bambancen halittu masu yawa, musamman tsakanin mazauna yankunan bakin teku na kudu maso gabas da kudu.
Strauss ya lura cewa bincike game da ilimin halittar jiki a cikin 2000s ya riga ya ba da shawarar rashin daidaituwa tsakanin waɗannan al'ummomin, wanda binciken kwayoyin halitta ya goyi bayan. An gano cewa yawancin mutanen bakin teku ba su keɓe ba, amma a kai a kai suna yin musayar kwayoyin halitta tare da ƙungiyoyin cikin gida. Dole ne wannan tsari ya kasance yana gudana cikin dubban shekaru kuma ana tunanin ya haifar da bambancin yanki na sambaquis.
A lokacin da ake gudanar da bincike kan bacewar wannan al'umma ta bakin teku, wacce ta kunshi mafarauta na farko da masu tarawa na Holocene, samfuran DNA da aka yi nazari sun nuna cewa, sabanin al'adar Neolithic na Turai na canza al'umma gaba ɗaya, abin da ya faru a wannan yanki shine canjin al'adu, wanda ya haɗa da raguwar ginin tsakiyar harsashi da ƙari na tukwane na masu ginin sambaqui. Misali, kwayoyin halitta da aka samu a Galheta IV (wanda ke cikin jihar Santa Catarina) - wurin da ya fi daukar hankali daga wannan lokacin - bai ƙunshi bawo ba, sai dai yumbu, kuma yana kwatankwacin sambaquis na yau da kullun a wannan batun.
Strauss ya bayyana cewa, sakamakon binciken da aka yi a shekara ta 2014 kan tukwane daga sambaquis ya yi daidai da ra'ayin cewa ana amfani da tukwane don dafa kifi, maimakon kayan lambu na gida. Ya bayyana yadda mazauna yankin suka yi amfani da wata dabara daga cikin gida wajen sarrafa abincinsu na gargajiya.
An fara buga binciken ne a mujallar Nature a kan Yuli 31, 2023.
