Characterization of immunoglobulin gamma 1 from a monotreme, Tachyglossus aculeatus

Katherine Belov, Lars Hellman, Desmond W. Cooper

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

A full-length immunoglobulin gamma clone from the echidna (Tachyglossus aculeatus) was isolated from a spleen cDNA library. The clone was 1,664 base pairs long and encoded the entire open reading frame, incorporating the V, D, J and C regions. The echidna clone had approximately 41% identity and 67% similarity at the amino acid level with both marsupial and eutherian IgG molecules. The presence of IgG in the monotremes confirms that the appearance of IgG occurred prior to the separation of the three extant mammalian lineages, but after their separation from the reptilian lineage, pinpointing the date to between 310 and 170 million years ago. Phylogenetic analyses using the immunoglobulin sequence data strongly support the 'Theria' hypothesis, with the monotreme lineage diverging prior to the separation of the marsupial and eutherian lineages.
Original languageEnglish
Pages (from-to)1065-1071
Number of pages7
JournalImmunogenetics
Volume53
Issue number12
DOIs
Publication statusPublished - Mar 2002

Keywords

  • monotreme
  • immunoglobulin
  • evolution
  • IgG
  • IgY

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