I came across a very interesting article (Lumila Paula Menéndez, (2025), The antiquity and ancestral origin of humans in the americas: a five hundred year inquiry from a biological anthropology perspective. Journal of Anthropological Sciences Istituto Italiano di Antropologia, Review Vol. 102 (2024), pp. 7-67, doi7p.10.4436/jass10201) that summarizes all the theories about the peopling of America over the past centuries.
It makes good reading. In particular, it points out the shortcomings of scientific papers about this subject due to different sources of bias, lack of research, and the inconsistencies that can arise from DNA studies based on the "settings" or "initial parameters" defined by each author when using DNA analitical tools and software, a concept that I agree with 100%.
"It is essential to acknowledge that the results we have today are not without bias and may not fully represent the past. Some biases are intrinsic due to the preservation of old samples, while others are methodological, associated with different methods used, and there are geographic and geopolitical biases. Disciplinary bias arises when, for example, only cultural evidence is discussed without incorporating human biological data (and vice-versa). Geographic sampling bias occurs when, despite continental coverage in some studies, samples from South America and Central America are typically underrepresented. Studies often include a few early Holocene individuals to infer biological relationships among populations or test dispersion models (Hubbe et al. 2009; Galland and Friess 2016; von Cramon-Taubadel et al. 2017). Due to this geographical bias, archaeological sites from Latin American countries are not frequently mentioned in the literature (or the same few ones are cited over and over), perpetuating geopolitical imbalances between researchers coming from central and peripheral countries (Yañez et al. 2023). Moreover, early Holocene individuals in these studies often derive from the same few archaeological localities, potentially underestimating the wide regional variation during that period. This sample bias may impact the perception of early Holocene variation due to incomplete sampling of a highly structured population across time. After the surge of aDNA studies, some misconceptions have emerged, such as the expectation that genetic results can answer more questions about human history than realistically possible. Contrary to common belief, interpretations based on genetic results should be approached catiously. These interpretations often rely on a small number of poorly preserved samples (i.e., aDNA molecules being usually short and damaged), constituting less than 1% of Native Americans’ variation. Additionally, various decisions made during the workflow, including molecular clock calibration, reference genomes used for sequence alignment, genotype imputation, and the selection of outgroups, significantly impact the obtained results (Axelsson et al. 2008; Orlando et al. 2021). While genetic data, in combination with other information sources like archaeology can contribute to models determining approximate population divergence (Raff 2022), it is crucial to recognize that genetic results can be misleading (Steeves 2023)..."
We all believe what we want to believe and ignore the facts that we don't like.
The Ancient DNA from Mengzi Ren
This is an example of how DNA data lead to wrong conclusions. This case went from proving Amerindians were linked to people living in Yunnan 14,000 years ago, to contamination by modern Han Chinese who manipulated the ancient remains! It took 3 years for someone to set the record straight.
A paper published in 2022 found affinities between the 14.000-year-old remains of a woman from Southern China, and Native Americans ( Zhang, X., Ji, X., Li, C., Yang, T., Huang, J., Zhao, Y., Wu, Y., Ma, S., Pang, Y., Huang, Y., et al. (2022). A Late Pleistocene human genome from Southwest China. Curr Biol 32, 3095–3109 e3095. doi:10.1016/j.cub.2022.06.016.)
The authors found that "14,000-years-ago human remains (Mengzi Ren, MZR) unearthed in Southwest China. MZR represents an early diversified human lineage in eastern Asia where they detect a clear genetic stratification of ancient populations. MZR deeply links to the East Asian ancestry that contributed to First Americans."
However, earlier this year, it was later found to be based on dubious data (Tabin, D., Patterson, N., Mah, M., and Reich, D. (2025). Concerns about ancient DNA sequences reported from a Late Pleistocene individual from Southeast Asia. Current Biology 35, R212–R213. doi:10.1016/j.cub.2024.10.012).
A final critique of the original paper was published by the same authors shortly after, and reported that the "ancient" DNA "data have specific affinity to modern Han Chinese and other related populations. This is a priori surprising given the date and location of the MZR individual. This affinity is so strong that MZR can be well modeled as entirely Han with added noise. Neither of these traits are shared with other ancient Southeast Asians and both raise additional concerns regarding the reliability of the MZR data. Contamination seems more plausible than a population with Han-like ancestry existing in Yunnan province 14 thousand years ago." (Tabin D, Patterson N, Mah M, Reich D. Addendum to Ancient DNA data from Mengzi Ren, a Late Pleistocene individual from Southeast Asia, cannot be reliably used in population genetic analysis. bioRxiv. 2025 Mar 26:2025.03.24.645126. doi: 10.1101/2025.03.24.645126. PMID: 40196503; PMCID: PMC11974788.).
Ancient DNA analysis involves complex procedures, and each step of the process, from extracting the sample, to sequencing it can affect the accuracy of the outcome. The following article: Anastasia V. Poznyak, Tatyana Vladimirovna Kirichenko et al., (2024). Ancient DNA studies: Common limitations and Genotyping, Journal of Angiotherapy, 8(6), 1-8, 9750, gives an enlightening overview of the process and its risks.
Patagonian Monsters - Cryptozoology, Myths & legends in Patagonia Copyright 2009-2025 by Austin Whittall ©
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