Evolutionary redefinition of immunoglobulin light chain isotypes in tetrapods using molecular markers

• DOI: 10.1073/pnas.0808800105
• Publication Date: 2008-10-22T00:45:53Z
• Authors: Sabyasachi Das; Nikolas Nikolaidis; Jan Klein; Masatoshi Nei
• Keywords: Isotype; Tetrapod (structure); Molecular evolution

The phylogenetic relationships of Ig light chain ( IGL ) genes are difficult to resolve, because these short and evolve relatively fast. Here, we classify the sequences from 12 tetrapod species into three distinct groups (κ, λ, σ isotypes) using conserved amino acid residues, recombination signal sequences, genomic organization as cladistic markers. From distribution markers conclude that earliest extant tetrapods, amphibians, possess isotypes: κ, σ. Of these, two (κ λ) also found in reptiles some mammals. λ isotype is all tetrapods tested date, whereas κ seems have been lost at least birds microbat. Conservation molecular suggests they associated with functional specialization isotypes. maps loci reveal multiple gene rearrangements occurred evolution species. These resulted interspecific variation lengths number order constituent genes, but overall has not changed.