Tetrapods Evolution

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This report aims to shed a little light on the evolution of immunoglobulins (Ig) in vertebrates as well as the hypothetical application of Ig in therapy against bovine tuberculosis. The discussion will entail several classes of animals. The simple scheme to the right explains the relation between the mentioned groups. For instance, it is evident that tetrapods include amphibians, reptiles, birds and mammals and that sharks are not teleost amongst other relations or lack thereof. Within all species we find some kind of immunological preparation to fight invaders. A few features are very wildly spread, like the event of antibody (Ab) gene duplication or deletion. This leads to a selection and evolutionary streamlining of immunological systems. http://academic.reed.edu/biology/professors/srenn/pages/teaching/web_2006/DJDAEC061204/images/phylogeny2003.png The vast Ab diversity is in part due to the genetic tricks, known as VDJ (or V(D)J) recombination. This takes place in lymphocytes and is a core concept to this report. The letters of the…show more content…
Immature B cells have constant μ type region, unlike T-Cell Receptors (TCR). The TCR has a V region has an α and δ part and there can can rearrange to 2 sets of (D)JC. This results in an δ or α chain. These 2 different kinds are in fact for 2 different TCR's corresponding to two types of T-cells. One for MHC class 2 (CD4+) and one for MHC class 1(CD8). Also tetrapods are the group with the the most diverse Ab. There are 5 prevalent classes in mammals, and each has specialized isotypes which serve to fine tune the immune response. By far for most mammalian Ig can be classified in 5 categories: IgM, IgD, IgG, IgE and IgA with their respective isotypes. Each isotype differs in its specific target and its ability to, for instance, activate the complement

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