ABSTRACT
Alphaglobin and carbonic anhydrase I coding sequences and part of their flanking untranslated regions were isolated from a cDNA library of the opossum Monodelphis domestica. This paper describes their characteristics and presents a brief phylogenetic analysis of these sequences and related ones.
Subject(s)
Carbonic Anhydrase I/genetics , DNA, Complementary/genetics , Immunoglobulins, Intravenous/genetics , Opossums/genetics , Animals , Polymerase Chain Reaction , Sequence Analysis, DNA , Vertebrates/geneticsABSTRACT
The neuromodulatory effects of dopamine on the central nervous system of craniates are mediated by two classes of G protein-coupled receptors (D1 and D2), each comprising several subtypes. A systematic isolation and characterization of the D1 and D2-like receptors was carried out in most of the Craniate groups. It revealed that two events of gene duplications took place during vertebrate evolution, before or simultaneously to the emergence of Gnathostomes. It led to the conservation of two-to-four paralogous receptors (subtypes), depending on the species. Additional duplication of dopamine receptor gene occurred independently in the teleost fish lineage. Duplicated genes were maintained in most of the vertebrate groups, certainly by the acquisition of a few functional characters, specific of each subtypes, as well as by discrete changes in their expression territories in the brain. The evolutionary scenario elaborated from these data suggests that receptor gene duplications were the necessary conditions for the expansion of vertebrate forebrain to occur, allowing dopamine systems to exert their fundamental role as modulator of the adaptive capabilities acquired by vertebrate species.
Subject(s)
Evolution, Molecular , Gene Duplication , Receptors, Dopamine/genetics , Animals , Nervous System Physiological Phenomena , Phylogeny , Receptors, Dopamine/classification , Receptors, Dopamine/physiology , Vertebrates/genetics , Vertebrates/physiologyABSTRACT
During the evolution of Metazoa, the mitochondrial genome has remained practically unchanged as indicated by its small size and constant gene content in each lineage, although several evolutionary processes have taken place. In contrast, the nuclear genome of Metazoa has undergone dramatic changes, as is demonstrated by some entire genomes completely sequenced so far. The expansion of gene families and the appearance of new functions and new regulatory circuits are among the most prominent features. Here, we report a description of the evolution of the p53 gene family as an example of expansion of both genetic complexity and gene expression of the nuclear genome.
