Do dental nonmetric traits actually work as proxies for neutral genomic data? Some answers from continental- and global-level analyses.

Objectives: Crown and root traits, like those in the Arizona State University Dental Anthropology System (ASUDAS), are seemingly useful as genetic proxies. However, recent studies report mixed results concerning their heritability, and ability to assess variation to the level of genomic data. The aim is to test further if such traits can approximate genetic relatedness, among continental and global samples.

Materials And Methods: First, for 12 African populations, Mantel correlations were calculated between mean measure of divergence (MMD) distances from up to 36 ASUDAS traits, and F distances from >350,000 single nucleotide polymorphisms (SNPs) among matched dental and genetic samples. Second, among 32 global samples, MMD and F distances were again compared. Correlations were also calculated between them and inter-sample geographic distances to further evaluate correspondence.

Results: A close ASUDAS/SNP association, based on MMD and F correlations, is evident, with r -values between .72 globally and .84 in Africa. The same is true concerning their association with geographic distances, from .68 for a 36-trait African MMD to .77 for F globally; one exception is F and African geographic distances, r = 0.49. Partial MMD/F correlations controlling for geographic distances are strong for Africa (.78) and moderate globally (.4).

Discussion: Relative to prior studies, MMD/F correlations imply greater dental and genetic correspondence; for studies allowing direct comparison, the present correlations are markedly stronger. The implication is that ASUDAS traits are reliable proxies for genetic data-a positive conclusion, meaning they can be used with or instead of genomic markers when the latter are unavailable.