Molecular evolution of the transferrin family and associated receptors

► Transferrins (TF) are an ancient family found in all metazoans. ► Multiple intragenic and gene duplications have created numerous variations. ► At least seven orthologs with different functions have been found in vertebrates. ► The number and types of TF receptors differ by ortholog and by family. ► Evolutionary comparisons provide clues to the function of individual residues.