Quantitative genetics of phosphorus content in the freshwater herbivore, <i>Daphnia pulicaria</i>

Phosphorus (P) is essential for growth of all organisms, and P content correlated with in most taxa. Although was initially considered to be a trait fixed at the species level, there growing evidence considerable intraspecific variation. Selection on such variation can thus alter rates which fluxes through food webs. Nevertheless, prior work describing sources extent were not genetically explicit, confounded by unknown genetic background evolutionary history. We constructed an F2 recombinant population dominant freshwater grazer, Daphnia pulicaria mitigate issues. recombinants exhibited rate, (0.49%–1.97%), use efficiency (PUE; 51–208 mg biomass/mg P), traits as hatching time resting eggs, common garden conditions. These results clearly demonstrate scope recombination generating ecologically relevant traits. The absence environmental selection likely component driving observed natural settings. phosphoglucose isomerase (PGI) genotype significantly associated contrary less rigorous designs, allelic PGI locus did explain PUE Daphnia, indicating that quantitative are under polygenic control. Together, these suggest although key traits, use, strong stabilizing selection, due rate size. Importantly, our observations anthropogenic alterations supply eutrophication could thereby rapidly altering role plays cycle lakes.