The study presents a new method for identifying DNA fragments from archaic humans (Neanderthals and Denisovans) without the need for reference genomes of these populations. Instead, a hidden Markov model (HMM) is used to analyze the density of genetic variants not found in the reference population (the so-called outgroup), which is free of archaic admixture. The main conclusions of the study are: The novel method detects archaic fragments of the genome based on the number of "private" DNA variants in an individual - that is, those that members of the reference population do not have. It does not require archaic genome data, making it possible to detect admixtures also from unknown archaic populations. Validation with simulations shows the method's high sensitivity and precision for admixtures above 2%, and the optimal probability threshold for detecting an archaic segment is 0.8. Application to Papuans allowed accurate estimation of the timing and extent of archaic admixtures. In Papuans, a total of 4.1-4.4% of archaic DNA was detected, of which about 1.5-1.8% is material unique to them, and the rest is shared with other non-African populations (derived mainly from Neanderthals). The time of admixture has been estimated at 888-1254 generations ago, with Neanderthal events earlier (about 2000 generations ago) and Denisovan events later and unique to the ancestors of Papuans. Distinguishing admixture sources: by comparing variants detected in Papuans with those in other populations, the researchers identified that most of the unique fragments came from Denisovans, while fragments shared with other non-Africans came from Neanderthals. The Denisovan fragments are longer than Neanderthal fragments, indicating later Denisovan admixture. The new method detects more Denisovan fragments than methods based on the Denisovan reference genome, suggesting that earlier analyses did not take into account all of the Denisovan diversity (because the reference genome comes from a population separate from the one that intermingled with Papuans). Contribution of Denisovans to other populations: traces of Denisovan DNA have also been detected in Southeast Asian and South Asian populations, although to a much lesser extent than in Papuans. Ability to detect admixture from unknown sources: some archaic fragments have no counterparts in the known genomes of Denisovans or Neanderthals - they may come from other, unidentified archaic populations or from underrepresented lineages of known groups. Universal applicability: the method can also be applied to other species (e.g., chimpanzees, bears or elephants) if we have a reference population free of admixture and a study group with the potential influence of a distinct evolutionary lineage. In conclusion, the study introduces an accurate, robust method for detecting archaic admixture in the absence of reference genomes and significantly expands our knowledge of the Denisovan ancestry of Papuans, also showing the potential to detect traces of extinct or unrecognized archaic populations.