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Lineage-restricted retention of a primitive immunoglobulin heavy chain isotype within the Dipnoi reveals an evolutionary paradox
- Publication Year :
- 2003
- Publisher :
- National Academy of Sciences, 2003.
-
Abstract
- The lineage leading to lungfishes is one of the few major jawed vertebrate groups in which Ig heavy chain isotype structure has not been investigated at the genetic level. In this study, we have characterized three different Ig heavy chain isotypes of the African lungfish,Protopterus aethiopicus, including an IgM-type heavy chain and short and long forms of non-IgM heavy chains. Northern blot analysis as well as patterns of VHutilization suggest that the IgM and non-IgM isotypes are likely encoded in separate loci. The two non-IgM isotypes identified inProtopterusshare structural features with the short and long forms of IgX/W/NARC (referred to hereafter as IgW), which were previously considered to be restricted to the cartilaginous fish. It seems that the IgW isotype has a far broader phylogenetic distribution than considered originally and raises questions with regard to the origin and evolutionary divergence of IgM and IgW. Moreover, its absence in other gnathostome lineages implies paradoxically that the IgW-type genes were lost from teleost and tetrapod lineages.
- Subjects :
- DNA, Complementary
African lungfish
Lineage (evolution)
Molecular Sequence Data
Evolution, Molecular
Phylogenetics
biology.animal
Animals
Amino Acid Sequence
Cloning, Molecular
Phylogeny
Gene Library
Protopterus
Genetics
Multidisciplinary
Sequence Homology, Amino Acid
biology
Fishes
Vertebrate
Biological Sciences
Blotting, Northern
biology.organism_classification
Isotype
Protein Structure, Tertiary
Immunoglobulin M
biology.protein
RNA
Immunoglobulin heavy chain
Immunoglobulin Heavy Chains
Caltech Library Services
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Accession number :
- edsair.doi.dedup.....d5c0e02d619dc65fb5033bcb73c26306