The exon numbers and lengths vary in different eukaryotic species. With increasing completed genomic sequences, it is indispensable to reanalyze the gene organization in diverse eukaryotic genomes. We performed a larg...The exon numbers and lengths vary in different eukaryotic species. With increasing completed genomic sequences, it is indispensable to reanalyze the gene organization in diverse eukaryotic genomes. We performed a large-scale comparative analysis of the exon-intron structure in 72 eukaryotic organisms, including plants, fungi and animals. We confirmed that the exon-intron structure varies massively among eukaryotic genomes and revealed some lineage-specific features of eukaryotic genes. These include a teleost-specific exon-intron structure pattern, relatively small introns and large exons in fungi and algae, and a gradual expansion of introns in vertebrates. Furthermore, the conservation analysis of exon-intron boundaries indicates that several bases near splice site junctions are different in introns with variable length among different species. After comparison, we identified a trend showing increases in intron densities and lengths in diverse species from fungi, plants, invertebrates to vertebrates, while it was the opposite in relation to exon lengths. The statistical properties of eukaryotic genomic organization suggest that genome-specific features are preserved by diverse evolutionary processes, which paves way for further research on the diversification of eukaryotic evolution.展开更多
Four different Sox genes in Amur sturgeon Acipenser schrenckii and five Sox genes in chum salmon Oncorhynchus keta were identified for the first time in this paper, and there was no sexual difference for these genes i...Four different Sox genes in Amur sturgeon Acipenser schrenckii and five Sox genes in chum salmon Oncorhynchus keta were identified for the first time in this paper, and there was no sexual difference for these genes in these two fishes. For Amur sturgeon, the encoded amino acid sequences exhibited 98%, 98%, 98%, 86% of sequence homology with those reported for human SOX HMG box, respectively, and for chum salmon, the encoded amino acid sequences exhibited 93%,98%,98%,98%,96% of sequence homology with those reported for human SOX HMG box, respectively. Two different forms of Sox9 gene in chum salmon were found, and Sox9 contained a 303 bp and 258 bp introns in the HMG box for chum salmon respectively while 572 bp for Amur sturgeon. No clear similarity was observed between the introns in the Sox9 HMG box of different fishes, but the introns occur in the HMG box region between the second and third bases of the codon for arginine at residue 42 in HMG box for the three fishes, and obey the rule of “GT AG”. and the encoded amino acid sequences in the three Sox9 genes HMG box are very conservative in the two fishes (100% identification). Identification of these genes is a potential step in understanding development regulations including sex determination in Amur sturgeon.展开更多
文摘The exon numbers and lengths vary in different eukaryotic species. With increasing completed genomic sequences, it is indispensable to reanalyze the gene organization in diverse eukaryotic genomes. We performed a large-scale comparative analysis of the exon-intron structure in 72 eukaryotic organisms, including plants, fungi and animals. We confirmed that the exon-intron structure varies massively among eukaryotic genomes and revealed some lineage-specific features of eukaryotic genes. These include a teleost-specific exon-intron structure pattern, relatively small introns and large exons in fungi and algae, and a gradual expansion of introns in vertebrates. Furthermore, the conservation analysis of exon-intron boundaries indicates that several bases near splice site junctions are different in introns with variable length among different species. After comparison, we identified a trend showing increases in intron densities and lengths in diverse species from fungi, plants, invertebrates to vertebrates, while it was the opposite in relation to exon lengths. The statistical properties of eukaryotic genomic organization suggest that genome-specific features are preserved by diverse evolutionary processes, which paves way for further research on the diversification of eukaryotic evolution.
文摘Four different Sox genes in Amur sturgeon Acipenser schrenckii and five Sox genes in chum salmon Oncorhynchus keta were identified for the first time in this paper, and there was no sexual difference for these genes in these two fishes. For Amur sturgeon, the encoded amino acid sequences exhibited 98%, 98%, 98%, 86% of sequence homology with those reported for human SOX HMG box, respectively, and for chum salmon, the encoded amino acid sequences exhibited 93%,98%,98%,98%,96% of sequence homology with those reported for human SOX HMG box, respectively. Two different forms of Sox9 gene in chum salmon were found, and Sox9 contained a 303 bp and 258 bp introns in the HMG box for chum salmon respectively while 572 bp for Amur sturgeon. No clear similarity was observed between the introns in the Sox9 HMG box of different fishes, but the introns occur in the HMG box region between the second and third bases of the codon for arginine at residue 42 in HMG box for the three fishes, and obey the rule of “GT AG”. and the encoded amino acid sequences in the three Sox9 genes HMG box are very conservative in the two fishes (100% identification). Identification of these genes is a potential step in understanding development regulations including sex determination in Amur sturgeon.
