title: Are lungfish living fossils? Observation on the evolution of the opioid/orphanin gene family.
abstract: This minireview considers the possibility that there is a correlation between the slow rate of morphological change and speciation events that has been occurred within the lungfish lineage since the Permian period, and the apparent slow rate of divergence in the amino acid sequences of lungfish opioid precursor sequences. The status of lungfish as "living fossils" is considered.
authors.affiliation: Division of Cardiology, University of Colorado Health Sciences Center, Denver, CO 80262, USA.
authors.forename: Jenny
authors.initials: J
authors.lastname: Lee
authors.forename: Jasem
authors.initials: J
authors.lastname: Alrubaian
authors.forename: Robert M
authors.initials: RM
authors.lastname: Dores
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019143:Evolution, Molecular; D005399:Fishes / Q000235:genetics*; D005580:Fossils; D008969:Molecular Sequence Data; D018847:Opioid Peptides / Q000235:genetics*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D000097629:Nociceptin
chemical_list: D018847:Opioid Peptides; D000097629:Nociceptin