RESUMO
Transposable Elements (TEs) play important roles in the evolution of eukaryotic organisms. TEs widely distribute depending on their properties present in the genome. This study elucidated the molecular characteristics of TEs in land plants and animals using bioinformatics and in silico mutational approach. We discovered that the GC-rich class I TEs is the predominant class of TEs in animal, but the AT-rich class II TEs is prevalent in plants. The GC-rich class I TEs appears to be evolved within the animals. On contrary, the preserved in AT-rich in class II TEs is believed to be contributed in host defence systems.
Assuntos
Mapeamento Cromossômico/métodos , Elementos de DNA Transponíveis/genética , Evolução Molecular , Genoma de Planta/genética , Modelos Genéticos , Plantas/genética , Animais , Composição de Bases/genética , Sequência de Bases , Simulação por Computador , Dados de Sequência MolecularRESUMO
We analyzed 314,254 soybean expressed sequence tags (ESTs), including 29,540 from our laboratory and 284,714 from GenBank. These ESTs were assembled into 56,147 unigenes. About 76.92% of the unigenes were homologous to genes from Arabidopsis thaliana ( Arabidopsis). The putative products of these unigenes were annotated according to their homology with the categorized proteins of Arabidopsis. Genes corresponding to cell growth and/or maintenance, enzymes and cell communication belonged to the slow-evolving class, whereas genes related to transcription regulation, cell, binding and death appeared to be fast-evolving. Soybean unigenes with no match to genes within the Arabidopsis genome were identified as soybean-specific genes. These genes were mainly involved in nodule development and the synthesis of seed storage proteins. In addition, we also identified 61 genes regulated by salicylic acid, 1,322 transcription factor genes and 326 disease resistance-like genes from soybean unigenes. SSR analysis showed that the soybean genome was more complex than the Arabidopsis and the Medicago truncatula genomes. GC content in soybean unigene sequences is similar to that in Arabidopsis and M. truncatula. Furthermore, the combined analysis of the EST database and the BAC-contig sequences revealed that the total gene number in the soybean genome is about 63,501.