The paradigm of γδ high (artiodactyls and chickens) and γδ low (human and mice) species is still unresolved. Previous comparative analyses defined the peculiarity of the organization of ovine and bovine T cell receptor gamma (TRG1 and TRG2) loci in cassettes, each containing the basic recombinational unit. The two TRG loci in cattle and sheep as compared to the single human locus revealead that Bovidae and human loci, although not correlated in general structure, share extensive colinearity in the regulatory and intergenic as well as in the coding regions. On the other hand the phylogenetic conservation of the nine enhancer-like elements found in ovine and bovine compared with the single copy present in the human indicates that they play a key role in the functional organization of the Bovidae TRG loci. In this context the distribution of the “similarity peaks” (>70%) through the mVISTA program by analyzing variable (TRGV), joining (TRGJ) and constant (TRGC) genes as shared markers is applied to human, mouse, cattle, sheep and dog comparative maps to impute the ancestral mammalian immuno-subgenome. Distances between species dominated by duplications, deletions and inversions are presented in a first multispecies attempt, using ordered mapping data to reconstruct the evolutionary exchanges that preceded modern mammal organization of TRG regions.
Multispecies comparative immunogenomics: TRG loci as markers in reconstructing the evolutionary patway from ancestral to modern mammal genomes.
CICCARESE, Salvatrice Maria
2008-01-01
Abstract
The paradigm of γδ high (artiodactyls and chickens) and γδ low (human and mice) species is still unresolved. Previous comparative analyses defined the peculiarity of the organization of ovine and bovine T cell receptor gamma (TRG1 and TRG2) loci in cassettes, each containing the basic recombinational unit. The two TRG loci in cattle and sheep as compared to the single human locus revealead that Bovidae and human loci, although not correlated in general structure, share extensive colinearity in the regulatory and intergenic as well as in the coding regions. On the other hand the phylogenetic conservation of the nine enhancer-like elements found in ovine and bovine compared with the single copy present in the human indicates that they play a key role in the functional organization of the Bovidae TRG loci. In this context the distribution of the “similarity peaks” (>70%) through the mVISTA program by analyzing variable (TRGV), joining (TRGJ) and constant (TRGC) genes as shared markers is applied to human, mouse, cattle, sheep and dog comparative maps to impute the ancestral mammalian immuno-subgenome. Distances between species dominated by duplications, deletions and inversions are presented in a first multispecies attempt, using ordered mapping data to reconstruct the evolutionary exchanges that preceded modern mammal organization of TRG regions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
