IgH loci of American alligator and saltwater crocodile shed light on IgA evolution.

Immunoglobulin loci of two representatives of the order Crocodylia were studied from full genome sequences. Both Alligator mississippiensis and Crocodylus porosus have 13 genes for the heavy chain constant regions of immunoglobulins. The IGHC locus contains genes encoding four immunoglobulins M (IgM), one immunoglobulin D (IgD), three immunoglobulins A (IgA), three immunoglobulins Y (IgY), and two immunoglobulins D2 (IgD2).

Immunoglobulin light chains in medaka (Oryzias latipes).

The gene segments encoding antibodies have been studied in many capacities and represent some of the best-characterized gene families in traditional animal disease models (mice and humans). To date, multiple immunoglobulin light chain (IgL) isotypes have been found in vertebrates and it is unclear as to which isotypes might be more primordial in nature. Sequence data emerging from an array of fish genome projects is a valuable resource for discerning complex multigene assemblages in this critical branch point of vertebrate phylogeny.

Immunoglobulin genes of the turtles.

The availability of reptile genomes for the use of the scientific community is an exceptional opportunity to study the evolution of immunoglobulin genes. The genome of Chrysemys picta bellii and Pelodiscus sinensis is the first one that has been reported for turtles. The scanning for immunoglobulin genes resulted in the presence of a complex locus for the immunoglobulin heavy chain (IGH).

Snakes antibodies.

Immunoglobulins are basic molecules of the immune system of vertebrates. In previous studies we described the immunoglobulins found in two squamata reptiles, Anolis carolinensis and Eublepharis macularius. Snakes are squamata reptiles too but they have undergone an extreme evolutionary process.

Immunoglobulin heavy chains in medaka (Oryzias latipes).

Background: Bony fish present an immunological system, which evolved independently from those of animals that migrated to land 400 million years ago. The publication of whole genome sequences and the availability of several cDNA libraries for medaka (Oryzias latipes) permitted us to perform a thorough analysis of immunoglobulin heavy chains present in this teleost.

Results: We identified IgM and IgD coding ESTs, mainly in spleen, kidney and gills using published cDNA libraries but we did not find any sequence that coded for IgT or other heavy chain isotypes described in fish.