Molecular clock and gene function.
Molecular phylogenies based on the molecular clock require the comparison of orthologous genes. Orthologous and paralogous genes usually have very different evolutionary fates. In general, orthologs keep the same functions in species, whereas, particularly over a long time span, paralogs diverge functionally and may become pseudogenes or get lost. In eukaryotic genomes, because of the degree of redundancy of genetic information, homologous genes are grouped in gene families, the evolution of which may differ greatly between the various organisms. This implies that each gene in a species does not always have an ortholog in another species and thus, due to multiple duplication events following a speciation, many orthologous clades of paralogs are generated. We are often dealing with a one-to-many or many-to-many relationship between genes. In this paper, we analyze the evolution of two gene families, the p53 gene family and the porin gene family. The evolution of the p53 family shows a one-to-many gene relationship going from invertebrates to vertebrates. In invertebrates only a single gene has been found, while in vertebrates three members of the family, namely p53, p63, and p73, are present. The evolution of porin (VDAC) genes (VDAC1, VDAC2, and VDAC3) is an example of a many-to-many gene relationship going from yeast to mammals. However, the porin gene redundancy found in invertebrates and possibly in some fishes may indicate a tendency to duplicate the genetic material, rather than a real need for function innovation.
Dipartimento di Biochimica e Biologia Molecolare, Università di Bari, via Orabona 4, 70126, Bari, Italy. saccone@area.ba.cnr.it
Cecilia
C
Saccone
Corrado
C
Caggese
Anna Maria
AM
D'Erchia
Cecilia
C
Lanave
Marta
M
Oliva
Graziano
G
Pesole
D000818:Animals; D004268:DNA-Binding Proteins / Q000235:genetics; D019143:Evolution, Molecular; D005796:Genes; D016147:Genes, Tumor Suppressor; D007448:Invertebrates / Q000235:genetics; D007473:Ion Channels / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins / Q000235:genetics; D005810:Multigene Family; D009687:Nuclear Proteins / Q000235:genetics; D010802:Phylogeny; D018272:Porins / Q000235:genetics* / Q000378:metabolism; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53 / Q000235:genetics*; D025521:Tumor Suppressor Proteins; D014714:Vertebrates / Q000235:genetics; D050995:Voltage-Dependent Anion Channel 1; D050996:Voltage-Dependent Anion Channel 2; D050994:Voltage-Dependent Anion Channels
C081876:CKAP4 protein, human; D004268:DNA-Binding Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D009687:Nuclear Proteins; D018272:Porins; C000606460:TP73 protein, human; C000606368:Trp73 protein, mouse; D000072160:Tumor Protein p73; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; C480078:Vdac3 protein, mouse; D050996:Voltage-Dependent Anion Channel 2; D050994:Voltage-Dependent Anion Channels; D050995:Voltage-Dependent Anion Channel 1