A screening approach for selecting fossils for molecular analysis.

IBARRA DAMIÁN; BRAMBILLA L; HOFER C; BRUN LR

La Rioja

Simposio; VII Simposio Mioceno Pleistoceno del centro y norte de Argentina; 2023

Universidad Nacional de la Rioja (UNLAR).

Biological remains preserved in fossils, such as DNA and proteins, harbor a wealth of invaluable genetic information for establishing the phylogenetic position of extinct organisms. While DNA can yield more substantial insights, its lifespan is comparatively limited in contrast to that of proteins. Consequently, proteins present a viable avenue for scrutinizing ancient taxa. Here, we have devised an expeditious sampling method to discern materials with potential for these molecules preservation, aimed at future molecular analyses. We scrutinized the osteoderms of Panochthus tuberculatus MMCNP P2019-07 and Glyptodon reticulatus MMCNP P2019-04 from the Pachamama Museum in Santa Clara del Mar. We proceeded by sectioning the osteoderms and subjecting them to direct staining using Coomassie Blue which exhibits notable affinity for protein. The recently exposed surfaces of the osteoderms were immersed in a solution of this dye in concentration 0.15% p/v) diluted in 50:10:40 ratio of methanol:acetic acid:water for 10 minutes. Then, the surface was submerged in the same solvent mixture without the dye for a decolorization step aimed at uncovering regions with preserved proteins. As a result, we observed that the P. turbeculatus specimen exhibited protein preservation proximal to its internal side, while in contrast, G. reticulatus specimen displayed protein preservation in its mid-region of spongy tissue and localized áreas near exposed surface. Both samples evinced heterogeneous protein preservation patterns, and this method expedited the determination within minutes as to whether specimens retained proteins, thereby facilitating their selection for subsequent analyses.