Lactate Dehydrogenase as a Candidate Genomic Marker of Climate Change in Mammals?

Thomas Stocker 

Climate change imposes metabolic and thermal stress on mammals, yet genomic markers that track lineage specific adaptation remain limited. Lactate dehydrogenase (LDH), a central enzyme in lactate metabolism and anaerobic stress response, has not previously been evaluated for its evolutionary association with climate change induced selection. Here, comparative genomics across 14 mammalian species and population level reanalysis of American Pika and Bank Vole datasets were used to assess LDH gene family evolution under recent and historic climate change. LDHA, LDHB and LDHD exhibited lineage specific signatures of selection, with pinnipeds showing consistent gene family expansion and elevated dN/dS across all paralogs. Bank Vole transcriptome screening revealed high polymorphism density in LDHB and LDHD, placing both genes within the top 80th percentile of evolving transcripts and consistent with historic and recent climate driven genomic change. These findings identify LDH gene families as candidate genomic markers of mammalian climate adaptation. Functional validation is required to determine whether LDH polymorphisms causally contribute to climate linked physiological resilience.