Do Biological Distances Reflect Genetic Distances? A Comparison of Craniometric and Genetic Distances at Local and Global Scales

Now a standard part of the bioarchaeological toolkit, biological distance (biodistance) analyses are conducted to reveal intra-and inter-population relationships as well as to infer the microevolutionary events responsible for their formation and maintenance. A common rationale for the use of biodistances is that they highly correlate with selectively neutral genetic distances. We test this presumed correlation at two scales (local and global) with limitations of bioarchaeological analyses in mind. Bioarchaeological studies often rely on fragmentary cranial or decayed genetic material to estimate biological or genetic distances, respectively. We explore inter-individual relationships between cranial and genetic distances using individuals from an archaeological mortuary site, and inter-population relationships using matched, globally-distributed population samples. Our findings suggest that fragmentary data sources often used in distance analyses, skeletal or genetic, should be utilized with caution. However, the more complete the specimen or well-preserved the DNA, the greater its reliability for inferring biological relatedness.