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Cited by 117Morphological variations and asymmetryGenetic diversity and population structureEvolution and Genetic Dynamics

Investigating the case of human nose shape and climate adaptation

Open access
Zaidi, Arslan A., Mattern, Brooke C., Claes, Peter, McEcoy, Brian, Hughes, Cris, Shriver, Mark D.·2017·PLOS Genetics
DOI 10.1371/journal.pgen.1006616PMC PMC5354252
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Abstract

The evolutionary reasons for variation in nose shape across human populations have been subject to continuing debate. An import function of the nose and nasal cavity is to condition inspired air before it reaches the lower respiratory tract. For this reason, it is thought the observed differences in nose shape among populations are not simply the result of genetic drift, but may be adaptations to climate. To address the question of whether local adaptation to climate is responsible for nose shape divergence across populations, we use Qst-Fst comparisons to show that nares width and alar base width are more differentiated across populations than expected under genetic drift alone. To test whether this differentiation is due to climate adaptation, we compared the spatial distribution of these variables with the global distribution of temperature, absolute humidity, and relative humidity. We find that width of the nares is correlated with temperature and absolute humidity, but not with relative humidity. We conclude that some aspects of nose shape may indeed have been driven by local adaptation to climate. However, we think that this is a simplified explanation of a very complex evolutionary history, which possibly also involved other non-neutral forces such as sexual selection.

AI snapshot

Written from the paper’s full text.

TL;DR

This study uses Qst–Fst comparisons and climate associations to test whether human nose shape divergence reflects local adaptation to climate. It finds nares width and alar base width exceed neutral expectations, and nares width correlates with temperature and absolute humidity, though the authors conclude climate adaptation is likely only part of a complex evolutionary history.

Key findings

  • Nares width (Qst = 0.467, p = 2.80E-03) and alar base width (Qst = 0.440, p = 4.90E-03) show accelerated divergence across populations; skin pigmentation also does (Qst = 0.642, p = 1.00E-04), while height does not (Qst = 0.177, p = 0.1433).
  • Nares width is significantly correlated with temperature (slope = 0.107, p = 2.37E-03) and absolute humidity (slope = 0.149, p = 6.97E-03), but not relative humidity (p = 0.100); alar base width is only mildly correlated with absolute humidity (p = 0.038).
  • Skin pigmentation is strongly correlated with UVB (T = 6.23, LRT = 55.20, p = 1.09E-13), used as proof of principle.
  • Nose shape traits are heritable in Europeans (hg2 range 0.401–0.657, N = 1,718), and between-population heritability estimates in Cape Verdeans include nares width hy2 = 0.226 and alar base width hy2 = 0.212 (N = 409).

Methods

  • 3D facial images were captured with the 3dMD system; 7,150 quasi-landmarks were mapped, and 709 nose-region quasi-landmarks were used to compute five linear distances and two areas. Qst–Fst analyses used four population groups: West African (N = 40), North European (N = 236), East Asian (N = 127), and South Asian (N = 73).
  • Qst–Fst comparisons used a non-parametric bootstrap with 10,000 pseudo-samples; Fst was estimated from 118,420 autosomal SNPs using Weir and Cockerham’s θ, and sensitivity to c/h2 assumptions was evaluated.
  • Climate adaptation was tested in 140 females using linear mixed models correcting for age, BMI, and genetic similarity, with climate values from parents’ birthplaces; heritability was estimated with GCTA in 1,825 Europeans and with local ancestry in 409 Cape Verdeans.

Limitations

  • The paper states that sampling of populations is sparse, higher-latitude sampling is limited, and results need replication in a larger set of populations; climate analyses used only females because genotype data were unavailable for males from Ireland and Poland.
  • The paper notes that heritability estimates were limited to individuals with West African and European ancestry and do not reflect variation within and across other populations.
  • The text makes evident that Qst inference depends on the c/h2 assumption, that the climate signal is weaker than for skin pigmentation, and that alternative non-neutral forces such as sexual selection remain speculative.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1371/journal.pgen.1006616

Cites

81 of 81 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 66 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    E. Asians tend to have the smallest noses in terms of external surface area.

    “E. Asians also tend to have the smallest noses in terms of external surface area.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Skin pigmentation shows a strong signal of accelerated divergence across populations (Qst = 0.642, p-value = 1.00E-04).

    “As expected, skin pigmentation shows a strong signal of accelerated divergence across populations (Qst = 0.642, p-value = 1.00E-04).”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The ratio c/h2 is equal to 1, i.e., the proportion of phenotypic variance due to additive genetic effects is the same among- and within-populations.
  • Findingown data

    Males tend to have bigger nostrils than females.

    “Males, on average, tend to have wider nares, longer nasal ridges, more outwardly protruding nasal tips, bigger nostrils, and a larger overall external surface area, compared to females (Fig 2, Table 1).”
    Quote in the paperNot a substantial claim
  • Findingown data

    All nasal measurements are significantly different across populations.

    “All nasal measurements are also significantly different across populations (S1 Table).”
    Quote in the paperNot a substantial claim
  • Findingown data

    Males tend to have longer nasal ridges than females.

    “Males, on average, tend to have wider nares, longer nasal ridges, more outwardly protruding nasal tips, bigger nostrils, and a larger overall external surface area, compared to females (Fig 2, Table 1).”
    Quote in the paperNot a substantial claim
  • May combine two claims. 28
  • Classified as probably not a substantial claim. 29

  • May combine two claims.

    Findingown data

    Nares width is largest in W. Africans and smallest in N. Europeans.

    “For example, nares width and alar base width are largest in W. Africans and smallest in N. Europeans.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Width of the nares is correlated with temperature and absolute humidity, but not with relative humidity.

    “We find that width of the nares is correlated with temperature and absolute humidity, but not with relative humidity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Alar base width is largest in W. Africans and smallest in N. Europeans.

    “For example, nares width and alar base width are largest in W. Africans and smallest in N. Europeans.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Nasal tip protrusion is greatest in N. Europeans and smallest in W. Africans and E. Asians.

    “Nasal tip protrusion is greatest in N. Europeans and smallest in W. Africans and E. Asians.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The positive slopes for nares width indicate that individuals from warm-humid climates tend to have wider nares, while individuals from cool-dry climates tend to have narrower nares.

    “The positive slopes indicate that individuals from warm-humid climates, on average, tend to have wider nares whereas individuals from cool-dry climates tend to have narrower nares.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The climate at the parents' birthplaces is a good proxy for the individual's ancestral climate.

  • May combine two claims.

    Findingnone given

    Both within- and between-population variation in nose shape are heritable.

    “In addition, we demonstrate that both within- and between-population variation in nose shape are heritable.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    The heritability for height in Europeans (hg2 = 0.394; N = 1,825) is similar to previously reported estimates.

    “The heritability for height in Europeans (hg2 = 0.394; N = 1,825) is similar to previously reported estimates [18].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [18] J Yang, 2010, Common SNPs explain a large proportion of the heritability for human height, Nat Genet source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Skin pigmentation has a critical value of c/h2 of 0.25, much lower than 1.

    “Skin pigmentation, which shows a very high Qst value, has a critical value of 0.25, which is much lower than 1 (Fig 4 and Table 2).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The ratio c/h2 is equal to 1, i.e., the proportion of phenotypic variance due to additive genetic effects is the same among- and within-populations.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Findingnone given

    All aspects of nose shape studied here are sexually dimorphic.

    “We mentioned earlier that all aspects of nose shape studied here are sexually dimorphic”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The measurements from Observer2 are slightly more internally consistent than Observer1.

    “The measurements from Observer2 are slightly more internally consistent than Observer1.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Both parents usually come from nearby regions, at least on a continental scale, and the climate values for the parents are quite similar.

    “Both parents usually come from nearby regions, at least on a continental scale (Fig 6), and the climate values for the parents are quite similar (S5 Fig).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For Observer1, nasal tip protrusion was the least precise distance measure with 95% of the standard deviations falling between 0.791mm and 1.165mm, with error for the remaining distances well under 1mm.

    “For Observer1, nasal tip protrusion was the least precise distance measure with 95% of the standard deviations falling between 0.791mm and 1.165mm, with error for the remaining distances well under 1mm.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    With the exception of nasal tip protrusion (ICC = 0.819), the ICCs for all other measures were quite high (ICC > 0.95).

    “With the exception of nasal tip protrusion (ICC = 0.819), the ICCs for all other measures were quite high (ICC > 0.95).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Temperature is only weakly correlated with nares width, especially compared with the correlation between skin pigmentation and UVB.

    “In fact, we show that temperature is only weakly correlated with nares width, especially when compared with the correlation between skin pigmentation and UVB.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The climate at the parents' birthplaces is a good proxy for the individual's ancestral climate.

  • Classified as probably not a substantial claim. May combine two claims.

    Premisecitation

    Several studies have found that most aspects of the skull seem to be evolving neutrally, while the shape of the nasal aperture appears to be more differentiated across human populations than expected under genetic drift.

    “Several studies have used this approach and found that while most aspects of the skull seem to be evolving neutrally, the shape of the nasal aperture appears to be more differentiated across human populations than expected under genetic drift [9,12,13].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [9] CC Roseman, 2004, Multivariate apportionment of global human craniometric diversity, Am J Phys Anthropol source

      Not checked in the free run.

    • cites [12] CC Roseman, 2004, Detecting interregionally diversifying natural selection on modern human cranial form by using matched molecular and morphometric data, Proc Natl Acad Sci U S A source

      Not checked in the free run.

    • cites [13] M Hubbe, 2009, Climate signatures in the morphological differentiation of worldwide modern human populations, Anat Rec source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Both height and skin pigmentation exhibit substantial variation within and across human populations, and are thought to be under positive selection in various populations.

    “Both height and skin pigmentation exhibit substantial variation within and across human populations, and are thought to be under positive selection in various populations [19–22].”
    Quote in the paperNot a substantial claim0 of 4 sources checked
    • cites [19] MC Turchin, 2012, Evidence of widespread selection on standing variation in Europe at height-associated SNPs, Nat Genet source

      Not checked in the free run.

    • cites [20] NG Jablonski, 2004, the Evolution of Human Skin and Skin Color, Annu Rev Anthropol source

      Not checked in the free run.

    • cites [21] RL Lamason, 2005, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, Science source

      Not checked in the free run.

    • cites [22] HL Norton, 2007, Genetic evidence for the convergent evolution of light skin in Europeans and East Asians, Mol Biol Evol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Inhaled air reaches 90% of the required temperature and humidity levels before reaching the nasopharynx, implicating the nasal cavity as the major conditioning apparatus in the respiratory tract.

    “In fact, inhaled air reaches 90% of the required temperature and humidity levels before even reaching the nasopharynx, implicating the nasal cavity as the major conditioning apparatus in the respiratory tract [4,5].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [4] LM Hanna, 1986, A Theoretical Model of Localized Heat and Water Vapor Transport in the Human Respiratory Tract, J Biomech Eng source

      Not checked in the free run.

    • cites [5] S Naftali, 2005, The Air-Conditioning Capacity of the Human Nose, Ann Biomed Eng source

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given

    Most previous studies of Qst-based craniofacial divergence employed anticonservative heritability assumptions that overestimate genetic differentiation and can lead to incorrect conclusions about selection versus drift.

    “While this might be true, most of these studies employed anticonservative heritability assumptions, which overestimate the genetic differentiation underlying a trait, and thus, lead to incorrect conclusions regarding the relative roles of selection and drift in driving phenotypic differences among populations.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    When Qst is much greater than Fst, trait divergence exceeds neutral expectations and can be attributed to divergent selection.

    “Thus, when Qst is much greater than Fst, trait divergence exceeds neutral expectations and can be attributed to divergent selection [11].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] MC Whitlock, 2009, Testing for spatially divergent selection: comparing QST to FST, Genetics source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    The efficacy of the conditioning process depends on the flow dynamics of the inspired air, which depend on the geometry of the nasal cavity and inlets.

    “Studies have shown that the efficacy of the conditioning process depends on the flow dynamics of the inspired air, which in turn, depend on the geometry of the nasal cavity and inlets [5,7].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [5] S Naftali, 2005, The Air-Conditioning Capacity of the Human Nose, Ann Biomed Eng source

      Not checked in the free run.

    • cites [7] SE Churchill, 2004, Morphological variation and airflow dynamics in the human nose, Am J Hum Biol source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Divergence in the shape of the external nose, at least between Europeans and Han Chinese populations, exceeds neutral expectations.

    “More recently, it was also reported that the divergence in the shape of the external nose, at least between Europeans and Han Chinese populations, also exceeds neutral expectations [14].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [14] J Guo, 2014, Variation and signatures of selection on the human face, J Hum Evol source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Skin pigmentation is known to have evolved in response to a geospatially varying selection pressure: exposure to ground level ultraviolet B radiation (UVB).

    “Skin pigmentation is also a good example of a phenotype which is known to have evolved in response to a geospatially varying selection pressure: exposure to ground level ultraviolet B radiation (UVB) [23].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [23] NG Jablonski, 2000, The evolution of human skin coloration, J Hum Evol source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Low humidity in the respiratory tract leads to impaired mucociliary function and increases the risk of both upper and lower respiratory tract infections.

    “Low humidity in the respiratory tract leads to impaired mucociliary function and increases the risk of both upper and lower respiratory tract infections [6].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [6] SH Randell, 2006, Effective mucus clearance is essential for respiratory health, Am J Respir Cell Mol Biol source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationown data

    The conclusion that additive genetic variance between populations might be less than within populations is limited because heritabilities were estimated in individuals with W. African and European ancestry only and do not reflect variation within and across other populations.

    “However, we are cautious of over-stating this conclusion since the heritabilities were estimated in individuals with W. African and European ancestry only and do not reflect the variation within and across other populations.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Interpretationreasoning

    If the true value of c/h2 is drastically lower than 1, phenotype-derived estimates of the among-population genetic variance and Qst will be inflated, resulting in false-positive conclusions regarding the role of selection in driving phenotypic differentiation.

    “If the true value of c/h2 is drastically lower than 1, phenotype-derived estimates of the among-population genetic variance, and hence, Qst will be inflated, resulting in false-positive conclusions regarding the role of selection in driving phenotypic differentiation.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    The opposite case (c/h2 < 1) is more plausible because environmental variation is expected to be large across geographically distant populations.

    “If anything, the opposite case (c/h2 < 1) is more plausible as we expect environmental variation to be large across geographically distant populations.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: Environmental variation is large across geographically distant populations.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Height seems to be under positive selection within European and African populations separately.

    “While height seems to be under positive selection within European and African populations separately [19,34], it does not appear to be driven by divergent selection pressures across the populations considered here.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [19] MC Turchin, 2012, Evidence of widespread selection on standing variation in Europe at height-associated SNPs, Nat Genet source

      Not checked in the free run.

    • cites [34] GH Perry, 2014, Adaptive, convergent origins of the pygmy phenotype in African rainforest hunter-gatherers, Proc Natl Acad Sci U S A source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationreasoning

    Assuming c/h2 > 1 is an anticonservative approach because it assumes that heritability across populations is higher than heritability within populations.

    “While this might be true for some traits (for example, see skin pigmentation in Table 3), this is an anticonservative approach in our opinion, because it assumes that the heritability across populations is higher than the heritability within populations.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Interpretationown data

    The effect of Northern European removal might be indicative of positive selection for lighter skin pigmentation and narrower nares in higher latitude populations.

    “This effect might be indicative of positive selection for lighter skin pigmentation and narrower nares in higher latitude populations.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The climate at the parents' birthplaces is a good proxy for the individual's ancestral climate.

  • May combine two claims.

    Interpretationown data

    Both phenotype-climate correlations (skin pigmentation vs UVB and nares width vs temperature) are driven primarily by the inclusion of Northern Europeans.

    “suggesting that both phenotype-climate correlations are driven primarily by the inclusion of N. Europeans.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The climate at the parents' birthplaces is a good proxy for the individual's ancestral climate.

  • May combine two claims.

    Premisecitation

    In a randomly mating admixed population, ancestry segments segregate randomly with respect to the environment, which decouples the between-population genetic effects on the phenotype from the environmental effects, allowing for the estimation of the genetic variance underlying a phenotype.

    “In a randomly mating admixed population, ancestry segments segregate randomly with respect to the environment, which decouples the between-population genetic effects on the phenotype from the environmental effects, allowing for the estimation of the genetic variance underlying a phenotype.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [39] A Darvasi, 2005, The beauty of admixture, Nat Genet source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Prior studies have shown that nasal aperture and nasal cavity shapes are correlated with temperature and humidity, with individuals from cold-dry climates having narrower nasal cavities than individuals from warm-humid climates.

    “Previously, several studies have shown that the shapes of the nasal aperture and nasal cavity are correlated with climate variables related to temperature and humidity such that individuals from cold-dry climates exhibit narrower nasal cavities compared to individuals from warm-humid climates [41,42].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [41] TR Yokley, 2009, Ecogeographic variation in human nasal passages, Am J Phys Anthropol source

      Not checked in the free run.

    • cites [42] ML Noback, 2011, Climate-related variation of the human nasal cavity, Am J Phys Anthropol source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Differences in skin pigmentation across human populations have evolved primarily in response to ultraviolet radiation.

    “multiple lines of evidence suggest that differences in skin pigmentation across populations have evolved primarily in response to ultraviolet radiation [17,20–22].”
    • Also stated in: § Discussion · boosted
      “Substantial evidence has accumulated supporting the hypothesis that differences in skin pigmentation across human populations have evolved largely in response to selection pressures imposed by exposure to ultraviolet radiation [20].”
    Quote in the paperSubstantial claim0 of 4 sources checked
    • cites [17] S Beleza, 2013, Genetic architecture of skin and eye color in an African-European admixed population. Spritz RA, editor, PLoS Genet source

      Not checked in the free run.

    • cites [20] NG Jablonski, 2004, the Evolution of Human Skin and Skin Color, Annu Rev Anthropol source

      Not checked in the free run.

    • cites [21] RL Lamason, 2005, SLC24A5, a putative cation exchanger, affects pigmentation in zebrafish and humans, Science source

      Not checked in the free run.

    • cites [22] HL Norton, 2007, Genetic evidence for the convergent evolution of light skin in Europeans and East Asians, Mol Biol Evol source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    The top four genetic PCs were included as covariates in the model to correct for population structure, which can inflate heritability estimates.

    “The top four genetic PCs were included as covariates in the model to correct for population structure, which can inflate heritability estimates [18,69,70].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [18] J Yang, 2010, Common SNPs explain a large proportion of the heritability for human height, Nat Genet source

      Not checked in the free run.

    • cites [69] SR Browning, 2011, Population structure can inflate SNP-based heritability estimates, Am J Hum Genet source

      Not checked in the free run.

    • cites [70] ME Goddard, 2011, Response to browning and browning, Am J Hum Genet source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Non-independence among observations due to genetic similarity was taken into account by allowing the observations to be correlated according to the SNP-based genome-wide kinship matrix.

    “We took non-independence among observations due to genetic similarity into account by allowing the observations to be correlated according to the SNP-based genome-wide kinship matrix.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Ecological selection and sexual selection could reinforce each other, accelerating phenotypic divergence across populations in spite of continued gene flow.

    “Indeed, ecological selection and sexual selection could reinforce each other, accelerating phenotypic divergence across populations in spite of continued gene flow [54].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [54] GS van Doorn, 2009, On the origin of species by natural and sexual selection, Science source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    The seven landmarks used for linear distances have been defined previously.

    “These landmarks have been defined previously [1,26] and their approximate positions are shown in Fig 1.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] LG Farkas, 1986, Geography of the nose: a morphometric study, Aesthetic Plast Surg source

      Not checked in the free run.

    • cites [26] VF Ferrario, 2007, Three-dimensional computerized anthropometry of the nose: Landmark representation compared to surface analysis, Cleft Palate-Craniofacial J source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Sex, age, and BMI were also included as covariates in the c estimation.

    “Sex, age, and BMI were also included as covariates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Quality-control steps sufficiently remove potential batch effects due to genotyping platform, as evidenced by a multidimensional scaling plot clustering individuals by ancestry and not by platform.

    “This sufficiently removes any potential batch effects due to platform as evidenced by the observation that in a multidimensional scaling plot, individuals cluster by ancestry and not by platform (S1 Fig).”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductcitation

    A spatially dense mesh of 7,150 quasi-landmarks was mapped onto each image and its reflection, resulting in homologous vertices and triangles across individuals.

    “A spatially dense mesh of 7,150 quasi-landmarks (QLs) was mapped onto each image and its reflection. As a result of this mapping, the vertices and triangles are homologous across individuals [80].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [80] P Claes, 2015, An investigation of matching symmetry in the human pinnae with possible implications for 3D ear recognition and sound localization, J Anat source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Study design and conductown data

    Data collection was carried out with informed consent of participants and with approval from institutional review boards.

    “Data collection was carried out with informed consent of participants and with approval from the institutional review boards (IRBs) at The Pennsylvania State University (IRB# 32341, IRB# 45727, IRB# 44929) and at The University of Illinois Urbana-Champaign (IRB# 13103).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisereasoning

    Sexual selection has likely played an important role in human evolution, as evidenced by sexual dimorphism in many physical traits.

    “Sexual selection has likely played an important role in human evolution, as evidenced by the presence of sexual dimorphism in many physical traits (e.g., height, waist-hip ratio, facial hair, and breasts to name a few).”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    A linear mixed model was used to test the relationship between phenotype and climate variables, while correcting for age and BMI.

    “We used a linear mixed model to test the relationship between phenotype and climate variables, while correcting for age and BMI.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Inhaled air reaches 90% of the required temperature and humidity levels before reaching the nasopharynx, implicating the nasal cavity, especially the turbinates, as the major conditioning apparatus in the respiratory tract.

    “Inhaled air reaches 90% of the required temperature and humidity levels before even reaching the nasopharynx, implicating the nasal cavity, especially the turbinates, as the major conditioning apparatus in the respiratory tract [4,5].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [4] LM Hanna, 1986, A Theoretical Model of Localized Heat and Water Vapor Transport in the Human Respiratory Tract, J Biomech Eng source

      Not checked in the free run.

    • cites [5] S Naftali, 2005, The Air-Conditioning Capacity of the Human Nose, Ann Biomed Eng source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Sensitivity curves were used to evaluate the behavior of Qst to cases where c < h2.

    “However, we used sensitivity curves to evaluate the behavior of Qst to cases where c < h2.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Within-population heritability equals among-population heritability (c = h2) when calculating Qst from phenotype data.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Study design and conductown data

    Sex, age, and BMI were included as covariates in the model for hg2 estimation.

    “Also included in the model were sex, age, and BMI.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductnone given

    Procrustes coordinates of original and reflected images were averaged to remove effects of bilateral asymmetry.

    “The Procrustes coordinates of the original and reflected image for each participant were then averaged to remove effects of bilateral asymmetry.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Global ancestry was included as a covariate to correct for ancestry stratification and any environmental variables that might covary with ancestry.

    “Global ancestry, calculated from the mean of local ancestry across all SNPs, was included as a covariate to correct for ancestry stratification and any environmental variables that might covary with ancestry [16,72].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [16] EJ Parra, 2004, Implications of correlations between skin color and genetic ancestry for biomedical research, Nat Genet source

      Not checked in the free run.

    • cites [72] I Halder, 2003, Measuring and using admixture to study the genetics of complex diseases, Hum Genomics source

      Not checked in the free run.

  • May combine two claims.

    Study design and conductown data

    The use of inverse melanin index does not affect conclusions; untransformed melanin index produces similar results.

    “Statistical testing was performed using the inverse of melanin index since it is more normally distributed (S7 Fig) but the use of untransformed melanin index produces similar results and does not affect our conclusions.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Generalized Procrustes Superimposition was carried out on original and reflected images to remove differences in position and orientation.

    “Generalized Procrustes Superimposition [24] was carried out on both sets of images (original and reflected) to remove differences in position and orientation.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [24] JC Gower, 1975, Generalized procrustes analysis, Psychometrika source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductown data

    The association between phenotypes and climate variables was tested using linear mixed models that correct for age, BMI, and genetic similarity.

    “The association between phenotypes and climate variables was tested using linear mixed models, which correct for age, BMI, and genetic similarity (Methods).”
    Quote in the paperSubstantial claim
51 of 51

  • The authors state this as an assumption.

    The ratio c/h2 is equal to 1, i.e., the proportion of phenotypic variance due to additive genetic effects is the same among- and within-populations.

    “We estimated Qst under the assumption that c/h2 = 1. In other words, we assume that the proportion of between-population variance in the trait due to additive genetic effects is the same as the proportion of within-population variance due to additive genetic effects.”

  • The paper relies on this without support.

    Most genetic variation in humans exists within populations.

    “which agrees with the fact that most of the genetic variation in humans exists within populations.”

  • The paper relies on this without support.

    Environmental variation is large across geographically distant populations.

    “as we expect environmental variation to be large across geographically distant populations.”

  • The paper relies on this without support.

    The nose functions to warm and humidify inspired air.

    “The choice of these climate variables follows from the functional importance of the nose in warming and humidifying inspired air.”

  • The paper relies on this without support.

    The climate at the parents' birthplaces is a good proxy for the individual's ancestral climate.

    “This was done to assign to each individual, a climate value that was most similar to their ‘ancestral’ climate.”

  • The authors state this as an assumption.

    Within-population heritability equals among-population heritability (c = h2) when calculating Qst from phenotype data.

    “studies often calculate Qst directly from phenotype data under the assumption that the within-population heritability (h2) is equal to the among-population heritability (c).”
    “Our approach is similar to previous studies in that we also estimated Qst assuming c = h2.”

  • The paper relies on this without support.

    Genetic variation between populations is less than genetic variation within populations for most phenotypes.

    “In fact, genetic variation between-populations is likely to be less than the genetic variation within-populations for most phenotypes.”

  • The paper relies on this without support.

    High values of Qst–Fst are indicative of divergent selection.

    “High values of Qst–Fst are indicative of divergent selection, and the empirical p-value for this test was determined by calculating the proportion of Qst–Fst values that are less than zero.”

  • The paper relies on this without support.

    The climate at the parents' birthplace represents the ancestral climate for each individual.

    “We used climate values at the parents’ birthplace to represent the ancestral climate for each individual.”

  • The paper relies on this without support.

    The Fst distribution from the 118,420 SNPs represents neutral genetic divergence.

    “Values of Fst were simulated by randomly sampling from the Fst of 118,420 SNPs (S3 Fig).”
10 of 10

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • The variation due to local ancestry that local-ancestry-based heritability estimation leverages has no clear relationship with between-group trait differences.

    “We show that the variation due to local ancestry that they leverage has no clear relationship with between-group trait differences.”

    From Heritability within groups is uninformative about differences among groups: Cases from behavioral, evolutionary, and statistical genetics (2024) · cites this paper as [16]

    The Results section (“Investigating heritability of nose shape within- and among-populations”; page unavailable) says local-ancestry variation represents genetic variation between populations. It explicitly treats the phenotypic variance explained by local ancestry as conceptually equivalent to the genetic contribution to between-population phenotypic variation, rather than having no clear relationship to it. (LLM, conf=0.87)

    Checked by a reasoning model — may be wrong.

    Experimental — accuracy not yet measured

  • Skin pigmentation is strongly associated with absolute latitude; populations further from the equator have lighter skin pigmentation.

    “As previously observed (Byard, 1981; Jablonski and Chaplin, 2010; Zaidi et al., 2017), we find that skin pigmentation is strongly associated with absolute latitude (R2=0.53, β=−1.18 on M index scale, p<2e-16); populations further from the equator have lighter skin pigmentation.”

    From An Unexpectedly Complex Architecture for Skin Pigmentation in Africans (2017) · cites this paper as Zaidi et al., 2017

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Table 1 labels area measurements in millimeters rather than square millimeters

    Minor

    Table 1 gives both area columns units of mm, but the methods specify mm2 for these measurements.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 1

  1. A Nucara, 2012, Handbook of Anthropometry, Handb Anthr, 91

Cited by

Sorted by citations

Related

Authors
Zaidi, A. A., Mattern, B. C., Claes, P., McEcoy, B., Hughes, C., & Shriver, M. D.
Affiliations
  • Pennsylvania State University (US)
  • KU Leuven (BE)
  • Trinity College Dublin (IE)
  • University of Illinois Urbana-Champaign (US)
Corresponding author
  • Zaidi, Arslan A.
  • Shriver, Mark D.
ORCID
Venue
PLOS Genetics
Publisher
Public Library of Science (PLoS)
Published
2017-03-16
Volume
13
Issue
3
Pages
e1006616
ISSN
  • 1553-7390 (ISSN-L)
  • 1553-7404
DOI
10.1371/journal.pgen.1006616
PMC
PMC5354252
OpenAlex
W2596158197
Semantic Scholar
0cb1254a036cffa43635d7a10c1fbd441ecc33df
Cited by
117
References
81
Citations by year
2026: 12 · 2025: 11 · 2024: 8 · 2023: 15 · 2022: 12 · 2021: 19 · 2020: 15 · 2019: 11 · 2018: 13 · 2017: 1
FWCI
15.16
Type
journal article
Language
en
Update notices
correction (2018-01-31)
Open access
Licence
Locations
  • PLoS Genetics (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Lirias (KU Leuven) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
  • Figshare (submittedVersion, cc-by)
Funders
  • U.S. Department of Defense
  • University of Pennsylvania
  • Pennsylvania State University
  • Vlaamse regering
  • University of Illinois at Urbana-Champaign
Topics
  • Physical Sciences › Mathematics › Geometry and Topology › Morphological variations and asymmetry
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Genetic diversity and population structure
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Genetics › Evolution and Genetic Dynamics
Keywords
climate change adaptation, local adaptation, nasal cavity, alar base width, genetic differentiation, air conditioning, absolute humidity, temperature, relative humidity, sexual selection, human evolution
MeSH terms
Adaptation, Physiological, Africa, Asia, Climate, Europe, Female, Genetics, Population, Geography, Humans, Humidity, Male, Nose, Selection, Genetic, Temperature, Genetic Drift, Black People, White People, Asian People

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-10.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-10.

Statistics and arithmetic are recomputed, not judged.

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