Evolution of an extreme hemoglobin phenotype contributed to the sub-Arctic specialization of extinct Steller's sea cows.

ABSTRACT: The extinct Steller's sea cow (Hydrodamalis gigas; †1768) was a whale-sized marine mammal that manifested profound morphological specializations to exploit the harsh coastal climate of the North Pacific. Yet despite first-hand accounts of their biology, little is known regarding the physiological adjustments underlying their evolution to this environment. Here, the adult-expressed hemoglobin (Hb; α₂β/δ₂) of this sirenian is shown to harbor a fixed amino acid replacement at an otherwise invariant position (β/δ82Lys→Asn) that alters multiple aspects of Hb function. First, our functional characterization of recombinant sirenian Hb proteins demonstrates that the Hb-O₂ affinity of this sub-Arctic species was less affected by temperature than those of livi

SUBMITTER: Signore AV 

PROVIDER: S-EPMC10284601 | biostudies-literature | 2023 Jun

REPOSITORIES: biostudies-literature