Assuntos
Amiloidose/patologia , Nefropatias/patologia , Adulto , Idoso , Amiloidose/metabolismo , Biópsia , Feminino , Humanos , Amiloidose de Cadeia Leve de Imunoglobulina , Cadeias kappa de Imunoglobulina/metabolismo , Cadeias lambda de Imunoglobulina/metabolismo , Mucosa Intestinal/patologia , Mucosa Intestinal/ultraestrutura , Rim/metabolismo , Rim/patologia , Rim/ultraestrutura , Nefropatias/metabolismo , Masculino , Pessoa de Meia-Idade , Reto/patologia , Reto/ultraestrutura , Estudos RetrospectivosRESUMO
How the structure and base composition of genes changed with the evolution of vertebrates remains a puzzling question. Here we analyzed 895 orthologous protein-coding genes in six multicellular animals: human, chicken, zebrafish, sea squirt, fruit fly, and worm. Our analyses reveal that many gene regions, particularly intron and 3' UTR, gradually expanded throughout the evolution of vertebrates from their invertebrate ancestors, and that the number of exons per gene increased. Studies based on all protein-coding genes in each genome provide consistent results. We also find that GC-content increased in many gene regions (especially 5' UTR) in the evolution of endotherms, except in coding-exons. Analysis of individual genomes shows that 3' UTR demonstrated stronger length and GC-content correlation with intron than 5' UTR, and gene with large intron in all six species demonstrated relatively similar GC-content. Our data indicates a great increase in complexity in vertebrate genes and we propose that the requirement for morphological and functional changes is probably the driving force behind the evolution of structure and base composition complexity in multicellular animal genes.
Assuntos
Composição de Bases/genética , Evolução Molecular , Homologia de Sequência de Aminoácidos , Vertebrados/genética , Regiões 3' não Traduzidas/genética , Regiões 5' não Traduzidas/genética , Animais , Biologia Computacional , Éxons/genética , Sequência Rica em GC/genética , Genoma , Humanos , Íntrons/genéticaRESUMO
Little is known about variation of nucleotide insertion/deletions (indels) within species. In Arabidopsis thaliana, we investigated indel polymorphism patterns between two genome sequences and among 96 accessions at 1215 loci. Our study identified patterns in the variation of indel density, size, GC content and distribution, and a correlation between indels and substitutions. We found that the GC content in indel sequences was lower than that in non-indel sequences and that indels typically occur in regions with lower GC content. Patterns of indel frequency distribution among populations were more consistent with neutral expectation than substitution patterns. We also found that the local level of substitutions is positively correlated with indel density and negatively correlated with their distance to the closed indel, suggesting that indels play an important role in nucleotide variation.