Threonine nitrogen isotopes reveal hidden physiological dimensions of mammalian ecology
Tejada, J. V.
Show abstract
Stable nitrogen isotopes of amino acids are widely used to reconstruct trophic position. Most applications rely on only two amino acids despite routinely measuring many others. Here, comparative amino acid {delta}15N values from 88 mammal species reveal that threonine records a physiological dimension beyond trophic position. Adding threonine to the canonical glutamate-phenylalanine framework reveals ecological differentiation obscured by broad dietary categories and opposite isotopic relationships between herbivores and secondary consumers. A mechanistic model links this variation to preferential intestinal utilization of threonine for mucin synthesis and predicts experimentally testable patterns of isotope partitioning. These findings show that amino acid {delta}15N values encode complementary dimensions of organismal ecology, expanding amino acid isotope analysis beyond trophic reconstruction to reveal physiological and ecological variation associated with dietary specialization.
Matching journals
The top 4 journals account for 50% of the predicted probability mass.
Similar papers in this journal
"Similar papers" are the closest papers from that journal in the model's embedding space. They show what the match is built on, but the ranking comes mostly from a classifier over the whole training set, not from these examples alone.