Phenotypic differences between highlanders and lowlanders in Papua New Guinea

Abstract

Objectives Altitude is one of the most demanding environmental pressures for human populations. Highlanders from Asia, America and Africa have been shown to exhibit different biological adaptations, but Oceanian populations remain understudied [Woolcock et al., 1972; Cotes et al., 1974; Senn et al., 2010]. We tested the hypothesis that highlanders phenotypically differ from lowlanders in Papua New Guinea, as a result of inhabiting the highest mountains in Oceania for at least 20,000 years. Materials and methods We collected data for 13 different phenotypes related to altitude for 162 Papua New Guineans living at high altitude (Mont Wilhelm, 2,300–2,700 m above sea level (a.s.l.) and low altitude (Daru, <100m a.s.l.). Multilinear regressions were performed to detect differences between highlanders and lowlanders for phenotypic measurements related to body proportions, pulmonary function, and the circulatory system. Results Six phenotypes were significantly different between Papua New Guinean highlanders and lowlanders. Highlanders show shorter height (p-value = 0.001), smaller waist circumference (p-value = 0.002), larger Forced Vital Capacity (FVC) (p-value = 0.008), larger maximal (p-value = 3.20e -4) and minimal chest depth (p-value = 2.37e -5) and higher haemoglobin concentration (p-value = 3.36e -4). Discussion Our study reports specific phenotypes in Papua New Guinean highlanders potentially related to altitude adaptation. Similar to other human groups adapted to high altitude, the evolutionary history of Papua New Guineans appears to have also followed an adaptive biological strategy for altitude.

Chronology of natural selection in Oceanian genomes

“…Future genomic work with Indigenous Australians and ancient Oceanian genomics will complement this analysis on the adaptive strategies of the first settlers. Moreover, functional genomics analyses and genetic association with adaptive phenotypic traits will be necessary to validate the identified candidate genes ( André et al., 2021 ; Dannemann and Romero, 2022 ). Our work reporting a chronology of natural selection in Oceanian genomes does however highlight the initial settlement of the north of Sahul as a major evolutionary PAGE in human history.…”

Positive selection in the genomes of two Papua New Guinean populations at distinct altitude levels

“…These additional datasets increased our sample size to a total of 262 PNG whole genomes with 60 individuals from Mount Wilhelm (PNG highlanders), 80 individuals from Daru (PNG lowlanders) and 122 individuals sampled in Port Moresby from different origins (PNG diversity set I) (Note S1, Tables S1-S2). We measured phenotypes associated with body proportion, pulmonary capacities and cardiovascular components in this PNG dataset 15 (Note S2, Table S3).…”

“…We used Genome-wide Efficient Mixed Model Association (GEMMA) (v0.98.4) 52 to detect if the candidate SNPs are associated with any phenotypes that we measured in the PNG highlanders, lowlanders and PNG diversity set I datasets (Note S16). As we did previously 15 , we corrected the haemoglobin concentration, blood pressure, heart rate and BMI for age and gender and the chest depth, waist circumference, weight, and pulmonary function measurements (FEV1, PEF and FVC) for age, gender and height using a multiple linear regression approach.…”

“…To increase our sample size, we included S1-S2). We measured phenotypes associated with body proportion, pulmonary capacities and cardiovascular components in this PNG dataset 15 (Note S2, Table S3). We combined these 262 sequences with published Papuan genomes (n=81, PNG diversity II) 30,[32][33][34][35] and high-coverage genomes from the 1000 Genomes project from Africa (n=207), East Asia (n=202) and Europe (n=190) 36 (Note S1).…”

“…CC-BY 4.0 International license perpetuity. It is made available under a preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in The copyright holder for this this version posted December 15, 2022. ; https://doi.org/10.1101/2022.12.15.520226 doi: bioRxiv preprint of highly correlated phenotypes 15 , we used a threshold for significance of 0.01 (0.05/5) to correct for the number of phenotypes tested.…”