Recovery of proteins preserved over time is challenging. Here we present the challenges unique to extracting information from samples preserved in tropical humid environments from ~ 2000 years B.P (iron-age teeth sample) collected from Long Long Rak rock shelter in Northwest Thailand; and from two ~35, 000 years B.P (late Pleistocene skull and mandible sample) from anatomically modern humans inhabiting West Mouth of Niah Caves in Borneo.
Evidence for lifestyles in challenging environments such as tropical rain forests is essential for understanding the adaptations of early anatomically modern humans. Tropical rain forests are considered difficult surroundings to inhabit long term and require biological and cultural adaptations to survive. The uniquely crystalline structures of these samples has preserved sufficient proteomic content to explore protein pathways, potential illness and the association of diets and lifestyle consequences.
We demonstrate that human proteomes can be successfully recovered from individuals inhabiting a tropical setting extending well into the Late Pleistocene. We also show the two important amelogenin protein isoforms allowing the determination of sex from preserved teeth samples. We describe a novel MRM method using the isoforms of both X-related and Y-related forms of the amelogenin protein. Together, these different samples provide valuable insight into societies living in pre-history.