TheBacho Kiro cave (Bulgarian:пещера "Бачо Киро") is situated 5 km (3.1 mi) west of the townDryanovo,Bulgaria, only 300 m (980 ft) away from theDryanovo Monastery. It is embedded in the canyons of the Andaka andDryanovo River. It was opened in 1890 and the first recreational visitors entered the cave in 1938, two years before it was renamed in honor ofBulgarian National Revival leader, teacher and revolutionaryBacho Kiro. The cave is a four-storey labyrinth of galleries and corridors with a total length of 3,600 m (11,800 ft), 700 m (2,300 ft) of which are maintained for public access and equipped with electrical lights since 1964. An underground river has over time carved out the many galleries that contain countless stalactone,stalactite, andstalagmitespeleothem formations of great beauty. Galleries and caverns of a 1,200 m (3,900 ft) long section have been musingly named as a popular description of this fairy-tale underground world. The formations succession:Bacho Kiro's Throne, The Dwarfs, The Sleeping Princess, The Throne Hall, The Reception Hall, The Haidouti Meeting-Ground, The Fountain and the Sacrificial Altar.[1][2]
The site has yielded the oldest human remains ever to be found in Bulgaria. At one of the earliest knownAurignacian burials (layer 11), two pierced animal teeth were found and ordered into the distinctBachokiran artifact assemblage.Radiocarbon dated to over 43,000 years ago, they currently represent the oldest known ornaments in Europe.[3] With an approximate age of 46,000 years,[4] human fossils consist of a pair of fragmentedmandibles including at least onemolar. Whether these early humans were in factHomo sapiens orNeanderthals was disputed[5][6] until morphological analysis of a tooth and mitochondrial DNA of bone fragments established that remains were those ofHomo sapiens. In samples F6-620 and AA7-738 identifiedmitochondrial haplogroup M, in samples WW7-240 and CC7-335 determined themitochondrial haplogroup N, in sample CC7-2289 identifiedmitochondrial haplogroup R, in sample of BK-1653 identifiedmitochondrial haplogroup U8.[7][8]
ThreeInitial Upper Paleolithic individuals (c. 44,000 to 40,000 years ago) from Bacho Kiro cave were each found to have relatively high levels of Neanderthal ancestry, with their genomes suggesting a recent Neanderthal ancestor in all three individuals perhaps six or seven generations back.
In the single dispersalOut of Africa theory, it is believed that populations related to the Initial Upper Palaeolithic population of Bacho Kiro cave contributed ancestry to later Asian populations, because of genetic similarity and to some early West Europeans such as the c. 35,000 year old individual from theGoyet Caves, Belgium, known as 'GoyetQ116-1'. Populations related to these earlier individuals did not contribute detectable ancestry to later European populations.
TheInitial Upper Paleolithic individuals from Bacho Kiro were closer to theTianyuan man, and to modern-day East Asians, Central Asians and Native Americans, than to Europeans or Africans.[9]
Phylogenetic position of ancient Upper Paleolithic Eurasian specimens.
However, in the multiple dispersalOut of Africa theory, East Asians are found to have a more distant split time from East African populations (73-88kya) compared to modern Europeans (57-76 kya)[10] which could mean that the Bacho Kiro remains could be from a migration ofanatomically modern humans from Asia.[11][12]
In 2022, a study determined that the IUP-affiliated Bacho Kiro remains were part of anInitial Upper Paleolithic wave (>45kya) "ascribed to a population movement with uniform genetic features and material culture" (Ancient East Eurasians), and sharing deep ancestry with other ancient specimens such as theUst'-Ishim man and theTianyuan man, as well as ancestors of modern-dayPapuans (Australasians). The Bacho Kiro population was also closely related to thePeștera cu Oase specimens, which both were associated with the IUP material culture in Europe, and got absorbed by the later Upper Paleolithic migration wave associated withWest Eurasians (represented by theGoyetQ116-1 andKostenki-14 remains).[13] The IUP-affiliated populations however contributed some ancestry to later Upper Paleolithic Europeans associated with theAurignacian culture and less to theGravettian culture.[14][13][15] Around 19% ancestry of the GoyetQ116-1 individual is derived from a Bacho Kiro IUP-like source, while up to 39% ancestry of theTianyuan man is derived from an IUP-affiliated source distantly related to the Bacho Kiro IUP remains, explaining the unusual affinity between GoyetQ116-1 and Tianyuan.[9]
Following that, later individuals from the Bacho Kiro cave, such as the c. 35,000 year old 'BK1653' were more closely related to modern European populations than to East Asians.[16][13]
^Milisauskas, Sarunas (1974).European Prehistory: A Survey. Springer.ISBN978-1-4419-6633-9. Retrieved8 June 2012.One of the earliest dates for an Aurignacian assemblage is greater than 43,000 BP from Bacho Kiro cave in Bulgaria ...
^Fewlass, Helen; Talamo, Sahra; Wacker, Lukas; Kromer, Bernd; Tuna, Thibaut; Fagault, Yoann; Bard, Edouard; McPherron, Shannon P.; Aldeias, Vera; Maria, Raquel; Martisius, Naomi L.; Paskulin, Lindsay; Rezek, Zeljko; Sinet-Mathiot, Virginie; Sirakova, Svoboda; Smith, Geoffrey M.; Spasov, Rosen; Welker, Frido; Sirakov, Nikolay; Tsanova, Tsenka; Hublin, Jean-Jacques (11 May 2020). "A 14C chronology for the Middle to Upper Palaeolithic transition at Bacho Kiro Cave, Bulgaria".Nature Ecology & Evolution.4 (6):794–801.doi:10.1038/s41559-020-1136-3.hdl:11585/770560.PMID32393865.S2CID218593433.
