生物技术专业英语part2.pptVIP

Major Research Areas of Bioinformatics Sequence analysis Since the Phage Φ-X174 was sequenced in 1977, the DNA sequences of hundreds of organisms have been decoded and stored in databases. These data are analyzed to determine genes that code for proteins, as well as regulatory sequences. A comparison of genes within a species or between different species can show similarities between protein functions, or relations between species (the use of molecular systematics to construct phylogenetic trees). With the growing amount of data, it long ago became impractical to analyze DNA sequences manually. Today, computer programs are used to search the genome of thousands of organisms, containing billions of nucleotides. These programs can compensate for mutations (exchanged, deleted or inserted bases) in the DNA sequence, in order to identify sequences that are related, but not identical. A variant of this sequence alignment is used in the sequencing process itself. 生物信息学的主要研究领域 序列分析 自从1977年Φ-X174噬菌体被测序以来，数百个生物体的DNA序列已经被译解并储存在数据库中。人们分析这些数据来确定编码蛋白质的基因，以及调控序列。在一个物种内或不同物种间进行基因比较，可以显示蛋白功能的相似性，或物种间的亲缘关系（用分子系统学来构建系统树）。随着数据的日益增长，人工分析DNA序列很久以前就是不可能的了。如今，计算机程序被用来有哪些信誉好的足球投注网站成千上万的生物含数十亿的核苷酸的基因组。这些程序可以补偿DNA序列中的突变（碱基的替换、删除或插入）， 以便找出那些相近但不相同的序列。此序列比对的一个变种已用于测序过程。 The so-called shotgun sequencing technique (which was used, for example, by The Institute for Genomic Research to sequence the first bacterial genome, Haemophilus influenza) does not give a sequential list of nucleotides, but instead the sequences of thousands of small DNA fragments (each about 600-800 nucleotides long). The ends of these fragments overlap and, when aligned in the right way, make up the complete genome. Shotgun sequencing yields sequence data quickly, but the task of assembling the fragments can be quite complicated for larger genomes. In the case of the Human Genome Project, it took several months of CPU time to assemble the fragments. Shotgun sequencing is the method of choice for virtually all genomes sequenced today,