Addendum to Figure 1: Conditional Model 2A – Solutrean → Pleistocene-Adapted Homo sapiens “Ice Age Sasquatch”: Ray Harwood

Addendum to Figure 1: Conditional Model 2A – Solutrean → Pleistocene-Adapted Homo sapiens “Ice Age Sasquatch” APA In-Text Integration Example: "...as shown in the conditional phylogeny (Figure 1), a Solutrean-derived Sasquatch would branch with Western European Upper Paleolithic populations and lack Denisovan introgression, whereas a Beringian relict would branch with Native Americans and show elevated Denisovan alleles. If one further hypothesizes a Solutrean population underwent strong directional selection during the Last Glacial Maximum [LGM, ∼26.5–19 kya], the resulting lineage could exhibit Pleistocene-specific adaptive alleles while remaining within H. sapiens [Model 2A]." 1. Updated Cladogram Description for Model 2A Add the following terminal branch under Branch 3b3b: Model 2 - Solutrean Sasquatch from the previous cladogram: Code └── Branch 3b3b: Model 2 - Solutrean Sasquatch │ └── Branch 3b3b1: Model 2A - LGM-Adapted Solutrean Sasquatch Label: "Hypothetical Sasquatch - Solutrean LGM-Adapted" Subtext 8pt: "Y-DNA R/I; mtDNA U/H; Denisovan ~0%; Neanderthal ~2%; Fixed alleles: UCP1-2L, FGF5-L374F, EDAR-V370A, GHRHR-E72X, SLC24A5-A111T" Line style: dashed blue, bolded, add "[Unconfirmed]" in blue 3 lines hidden Visual Encoding Update: Use bolded dashed blue line to distinguish Model 2A “LGM-adapted” from baseline Model 2 “Solutrean.” Add to legend: Bold dashed blue = Solutrean LGM-Adapted Model [Unconfirmed]. 2. Conditional Genetic Model: Solutrean → Pleistocene “Ice Age Sasquatch” Premise: If a small Solutrean population became geographically isolated in periglacial refugia of Europe or crossed the Atlantic ∼20–18 kya, and if subsequent LGM selective pressure fixed a suite of cold-adaptive, large-bodied, and hypertrichosis-related alleles, then the genome would remain H. sapiens but phenotypically distinct. This is a “plasticity-to-fixation” scenario, not speciation. 2.1 Candidate Loci for Dominant Pleistocene Adaptation Gene/Locus Function Hypothetical Derived Allele Phenotype if Fixed Evidence in H. sapiens UCP1 Brown adipose thermogenesis UCP1-2L promoter duplication Increased non-shivering heat, cold tolerance UCP1 variants in Arctic populations FGF5 Hair follicle cycle regulator FGF5-L374F loss-of-function Longer anagen phase = hypertrichosis LOF in long-haired dog breeds, woolly mammoth EDAR Ectodysplasin receptor EDAR-V370A + enhancer Thick hair shafts, increased eccrine glands Fixed in East Asians, Inuit; ancestral in Pleistocene GHRHR Growth hormone releasing hormone receptor GHRHR-E72X nonsense Constitutional gigantism via GH axis Pathogenic in humans; similar truncations in woolly mammoth SLC24A5 Skin pigmentation SLC24A5-A111T reversion Darker skin for UV protection in low-sun + snow glare Ancestral allele; fixed in Africans EPAS1 Hypoxia response Introgressed Denisovan haplotype High-altitude performance Seen in Tibetans; could introgress if Denisovan contact AMPD1 Muscle metabolism AMPD1-Q12X common null Shift to slow-twitch, endurance in cold ∼15% in Europeans Note: All above are H. sapiens genes. Fixation would not create a new species, but a locally adapted ecotype. This parallels Siberian, Inuit, and Tibetan adaptations. 2.2 Population Genetics Requirements Bottleneck: Effective population size Ne < 500 for >200 generations to drive rapid fixation via drift + selection. Isolation: No gene flow with post-LGM Europeans after ∼15 kya, preserving allele suite. mtDNA/Y-DNA: Would remain U/H and R/I, matching Upper Paleolithic Europeans. No Denisovan introgression unless contact occurred. Heterozygosity: Extremely low, with long runs of homozygosity [ROH > 10 Mb] expected. 3. Testing the Model with DNA If authentic “Sasquatch” tissue were recovered and sequenced, Model 2A would predict: Test Model 2A Prediction Result if Modern Contamination mtDNA haplogroup U5, U8, H1 – basal to modern Europeans H1, H3 common in lab personnel Y-DNA R1b-L278* or I-M170* basal branches R1b-M269 common in Europeans Denisovan % ∼0% ∼0% Neanderthal % ∼2% but in different haplotypes ∼2% modern European pattern ROH 500 Mb total, Ne < 500 Low ROH like modern Europeans Fixed derived alleles Homozygous for table 2.1 alleles Heterozygous or absent Ancient damage C→T deamination if >10 ky old No damage if modern Critical Distinction from Beringian Model: Model 2A lacks Denisovan alleles and carries European Y/mtDNA. Model 1 would show Q Y-DNA, A-D mtDNA, and Denisovan >0.1%.[Beringian] 4. Mainstream Scientific Caveats Solutrean Hypothesis Status: Genomic data from Anzick-1, USR1, and all pre-Clovis remains show closer affinity to Siberians/East Asians than to Europeans [Raghavan et al., 2014; Moreno-Mayar et al., 2018]. No R1b or U5 has been recovered from pre-Columbian Americas. “Mass Mutation” Implausibility: Fixation of multiple loss-of-function + gain-of-function alleles requires thousands of generations. The LGM lasted ∼7 ky, or ∼280 generations. Strong selection could fix 1–2 alleles, but not a full suite without severe inbreeding depression. Archaeological Record: No Solutrean laurel-leaf technology is dated after ∼17 kya in Europe. Clovis appears ∼13.5 kya. The 3,500-year gap and Atlantic distance make transmission unlikely. Fossil Absence: No large-bodied Pleistocene H. sapiens with hypertrichosis exists in the North American fossil record. Therefore, Model 2A remains a conditional thought experiment. It illustrates how comparative genomics would test a H. sapiens Pleistocene-adapted hypothesis if biological material were ever authenticated. 5. Updated APA Figure Caption Figure 1. Conditional cladogram of Homo sapiens populations and hypothetical Sasquatch lineages. Solid black branches = confirmed genomes. Dashed red = Model 1 Beringian relict. Dashed blue = Model 2 Solutrean. Bold dashed blue = Model 2A Solutrean LGM-adapted with fixed UCP1-2L, FGF5-L374F, EDAR-V370A, GHRHR-E72X alleles. All Sasquatch branches are unconfirmed and included for hypothesis testing only. Branch lengths illustrative. Node dates from Reich et al. and Raghavan et al..[2012][2014] References Moreno-Mayar, J. V., et al. (2018). Science, 362, eaav2621. Raghavan, M., et al. (2014). Nature, 505, 87–91. Reich, D., et al. (2012). Nature, 488, 370–374. Stanford, D. J., & Bradley, B. A. (2012). Across Atlantic Ice. Univ. of California Press.[6419][7481][7412]