A preprint published on August 11th, 2026 proposes an alternate explanation to the teeth protein shared by Denisovans and Homo erectus, suggesting different scenarios that could result in the same outcome and not require admixture or introgression from erectus into Denisovans.
This article was published in the non-peer-reviewed bioRxiv: No signal of a super-archaic origin of the Denisovan AMBN gene, a comment on the protein affinity of Homo erectus and Denisovan enamel proteins, Ioannis Patramanis, Frido Welker, Laurits Skov. bioRxiv 2026.08.11.744165; doi: https://doi.org/10.64898/2026.08.11.744165 and disputes the claims put forward by Quiamei Fu, et al., 2026, Enamel proteins from six Homo erectus specimens across China, Nature, https://doi.org/10.1038/s41586-026-10478-8
Background
Last May, I posted about the original paper by Fu et al., that reported that a variant of a tooth enamel protein (AMBN) found in 400,000 year-old Homo erectus specimens, known as (M273V) was also found in Denisovans, suggesting a "super-archaic introgression, some of which later passed to modern humans, are likely to have originated from H. erectus. Late Middle Pleistocene H. erectus may have coexisted with Denisovans in parts of East Asia, where these interactions are presumed to have occurred." However, this new research suggests other alternatives.
The image below is from the original paper (Fig. 4) and it shows "a possible model of gene flow related to AMBN(M273V) among H. erectus associated with the populations of Zhoukoudian, Hexian and Sunjiadong, Denisovans and modern humans." The red hexagon represents AMBN(M273V), which passes (right to left) from erectus into Denisovans, and through them, into modern humans.
The image also shows a new allele found only in erectus (yellow pentagon), called AMBN(A253G) absent in all other hominins (Denisovans, Neanderthals, Dmanisi, Homo antecessor, and modern humans).
Now those findings are disputed
The new paper by Patramanis et al., says that the erectus admixutre explanation of Fu et al., is based on an assumption: that the AMBN (M273V) variant found in Denisovans has a super-archaic origin (via erectus). The authors suggest that it isn't super-archaic. Instead, they say, there are four different possible explanations for the presence of that variant in both Denisovans and modern humans.
Below is Fig. 1 from Patramanis, 2026, with the alternatives B, C, D, and E, that could explain the presence of the allele. Alternative (A) is the one shown further up, in Fu et al.
These are the four possible alternatives:
- (B). In this case, the variant appears, by chance in Denisovans, who in turn pass it on to H. erectus and modern humans. In this case, the allele is relatively recent, and not super archaic. The erectus also carry their specific variant, AMBN(A253G).
- (C). The allele is Denisovan. That have admixed with erectus and received AMBN(A253G). This group is mistaken by Fu et al. to be erectus. They are actually admixed Denisovans.
- (D). This model is one where Homo erectus did not admix at all with Denisovans. The Denisovans are a structured population, and some carry the AMBN(A253G), others carry the AMBN (M273V), some carry the two or none.
- (E). This alternative excludes admixtures. The variant was present in the common ancestors of Denisovans, Neanderthals, erectus), but through incomplete lineage sorting (ILS), by chance this variant was only inherited by erectus and Denisovans, but not by Neanderthals or Homo sapiens. Later admixing passed it from Denisovans into modern humans.
I favor the original theory. Denisovans lived in East Asia, and had plenty of time to admix with erectus there. Let's wait for Fu et al.'s reply to this paper, and see what future research finds.
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