An Exploratory Genomic and Transcriptomic Analysis Between Choloepus didactylus and Homo sapiens

Background/Objectives: Sloths, a group of xenarthran mammals currently comprising six recognized distinct species, have been the focus of much physiological animal research due to their extremely slow metabolisms, deliberate movements, and their status as a species relatively unchanged for over 26 million years. However, despite all the effort aimed at understanding these unique characteristics, the sloth genome remains largely unexplored. Due to the link between genetics and observed traits, such an investigation could potentially lead to insights regarding the genetic basis of unique sloth behaviors and characteristics, such as slow movement, low metabolism, and longevity. Methods: In this exploratory investigation, we performed whole genomic and transcriptomic analysis of a female Choloepus didactylus (Linnaeus's Two-Toed Sloth). Through whole genome sequencing (WGS), the genetic overlap between female two-toed sloths and female humans was estimated in line with evolutionary biology. Results: Transcriptome analysis of peripheral blood mononuclear cells (PBMCs) showed significant differences between gene expression levels in two-toed sloths and humans related to metabolism, body temperature control, cell cycle regulation, telomere maintenance, circadian rhythm regulation, and cancer prevention. Conclusions: The discovered differences imply a relationship to the low metabolisms, slow movements, and longevity displayed by sloths. Future exploratory research will include additional testing to determine if these findings are universal among all recognized sloth species, as well as to address the relationship between specific gene and protein functions and observed traits.