[Theoretical analysis of the correspondence between the stages of evolutionary divergence and the functioning of multigene families of the immune system].
By means of phylogenetic comparison of main immunoglobulin-like multigene families (MF) and of different C-domain sequences representing them, the order of divergences of these MF in the process of evolution of the system was analysed. The order proved to be in good agreement with the ordered fashion of MF's involvement into recombinational rearrangements during the immune cell development. Indeed, according to topology of the tree for 34 C-domains, all MHC antigens are separated from the rest of Ig-like sequences, at first. Secondly, beta-chain of T-receptor is branched off the main stem of divergences, then there is a serium of divergences of CH-domains for different Ig-classes, and at last, kappa- and lambda-chains are separated. It is mu-chain of IgM which first of all branched off within an each group of isofunctional CH-sequences in the tree (CH1, CH2, CH3, CH4). The same order of events could be seen in ontogeny of the immune system. The results suggest that the appearance of a new MF of Ig-like type (or a new cluster of genetic segments within the MF) in the course of evolution could mean the addition of a new step in the regulatory system of immunologic gene expression already involved. In other words, this is unique example of recapitulation at the molecular-genetical level.
Rzhetskiĭ
A Iu
AIu
Rodin
S N
SN
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000235:genetics; D005075:Biological Evolution; D006801:Humans; D007107:Immune System / Q000276:immunology*; D007136:Immunoglobulins / Q000235:genetics; D008214:Lymphocytes / Q000276:immunology; D005810:Multigene Family; D010802:Phylogeny; D011995:Recombination, Genetic
D000596:Amino Acids; D007136:Immunoglobulins
Teoreticheskiĭ analiz sootvetstviia mezhdu étapami évoliutsionnoĭ divergentsii i funktsionirovaniia mul'tigennykh semeĭstv immunnoĭ sistemy.