Phenotype & Genetics of the Atacama Specimen
Garry Nolan (Invited Speaker)
Nolan Lab
Stanford University School of Medicine
The genetic provenance of the Atacama mummy was recently raised. The complexity of the case concerns the unusual morphologic features of the specimen balanced against the size of the specimen. Radiographic analysis of the specimen by a renowned expert in pediatric bone disorders showed features consistent with an age of 6-7 years, which is at obvious variance with the size of the specimen. DNA was prepared from a bone marrow specimen taken under controlled conditions with chain of custody specimen control. DNA sizing showed an average 200 base pairs, consistent with a “young” age of the specimen (likely less than 100 years leading to minimal degradation of DNA), and not “ancient” (where the DNA size could be as small as 35-50 base pairs). Whole genome analysis was undertaken with two successive genome runs for a total of ~30 fold over sequencing of the genome. Each run gave statistically identical variant calls, with the combined genomes matching well against the human reference genome (hg19_refGene). Phenotype-genotype analysis was undertaken on causal variants after standard population filtering. 54 potentially deleterious gene mutations were found, but after phenotype enrichment using the Human Phenotype Ontology system, 3 gene mutations of these 54 were found that are referenced in the known databases as correlated with short stature, abnormalities in bone ossification, and 10 ribs. Thus, the observed phenotype in the visual and radiographic analysis matches the genetic abnormalities found to a remarkable degree of accuracy. The conclusion can be suggested that the genetics of the specimen matches the observed morphology, and that explanations of misidentified diagnosis are likely incorrect. The genetic analysis undertaken does not allow us to conclude age at time of death.