Genome-Wide Prediction of Transcription Start Sites in Conifers

Classification of Promoter Sequences from Human Genome

We have developed a new method for promoter sequence classification based on a genetic algorithm and the MAHDS sequence alignment method. We have created four classes of human promoters, combining 17,310 sequences out of the 29,598 present in the EPD database. We searched the human genome for potential promoter sequences (PPSs) using dynamic programming and position weight matrices representing each of the promoter sequence classes. A total of 3,065,317 potential promoter sequences were found. Only 1,241,206 of them were located in unannotated parts of the human genome. Every other PPS found intersected with either true promoters, transposable elements, or interspersed repeats. We found a strong intersection between PPSs and Alu elements as well as transcript start sites. The number of false positive PPSs is estimated to be 3 × 10-8 per nucleotide, which is several orders of magnitude lower than for any other promoter prediction method. The developed method can be used to search for PPSs in various eukaryotic genomes.

The Complete Chloroplast Genome Sequence of Laportea bulbifera (Sieb. et Zucc.) Wedd. and Comparative Analysis with Its Congeneric Species

Laportea bulbifera (L. bulbifera) is an important medicinal plant of Chinese ethnic minorities, with high economic and medicinal value. However, the medicinal materials of the genus Laportea are prone to be misidentified due to the similar morphological characteristics of the original plants. Thus, it is crucial to discover their molecular marker points and to precisely identify these species for their exploitation and conservation. Here, this study reports detailed information on the complete chloroplast (cp) of L. bulbifera. The result indicates that the cp genome of L. bulbifera of 150,005 bp contains 126 genes, among them, 37 tRNA genes and 81 protein-coding genes. The analysis of repetition demonstrated that palindromic repeats are more frequent. In the meantime, 39 SSRs were also identified, the majority of which were mononucleotides Adenine-Thymine (A-T). Furthermore, we compared L. bulbifera with eight published Laportea plastomes, to explore highly polymorphic molecular markers. The analysis identified four hypervariable regions, including rps16, ycf1, trnC-GCA and trnG-GCC. According to the phylogenetic analysis, L. bulbifera was most closely related to Laportea canadensis (L. canadensis), and the molecular clock analysis speculated that the species originated from 1.8216 Mya. Overall, this study provides a more comprehensive analysis of the evolution of L. bulbifera from the perspective of phylogenetic and intrageneric molecular variation in the genus Laportea, which is useful for providing a scientific basis for further identification, taxonomic, and evolutionary studies of the genus.

Database of Potential Promoter Sequences in the Capsicum annuum Genome

In this study, we used a mathematical method for the multiple alignment of highly divergent sequences (MAHDS) to create a database of potential promoter sequences (PPSs) in the Capsicum annuum genome. To search for PPSs, 20 statistically significant classes of sequences located in the range from −499 to +100 nucleotides near the annotated genes were calculated. For each class, a position–weight matrix (PWM) was computed and then used to identify PPSs in the C. annuum genome. In total, 825,136 PPSs were detected, with a false positive rate of 0.13%. The PPSs obtained with the MAHDS method were tested using TSSFinder, which detects transcription start sites. The databank of the found PPSs provides their coordinates in chromosomes, the alignment of each PPS with the PWM, and the level of statistical significance as a normal distribution argument, and can be used in genetic engineering and biotechnology.

Plant Biology and Biotechnology: Focus on Genomics and Bioinformatics

The study of molecular mechanisms of plant stress response is important for agrobiotechnology applications as it was discussed at series of recent bioinformatics conferences [...].