Of four species at different evolutionary distances to demonstrate the multistep process of comparative sequence analysis,Īnd discuss several of the public resources available for these studies. We also compare a small interval of human chromosome 7q31 with DNA sequences The algorithms commonly used in these studies. Here we review the basis for selecting DNA sequences of speciesĪt appropriate evolutionary distances for comparative analysis depending on the biological question being addressed, and describe By comparing the genomic sequences of species at differentĮvolutionary distances, one can identify coding sequences and conserved noncoding sequences with regulatory functions, andĭetermine which sequences are unique for a given species. Sequences tend to evolve at a slower rate than nonfunctional sequences. Such as transcriptional regulatory regions, noncoding RNA genes, and elements involved in chromosome structure and function.Ĭomparing the DNA sequences of different species is a powerful method for decoding genomic information, because functional Moreover, current annotation methods are largely unable to identify reliably other types of functional elements, In some cases only a fraction of the sequences comprising a gene are identified and some genes are missedĮntirely. The results of database similarity searches and gene-predicting algorithms to identify coding sequences with good but notĬomplete accuracy. The existing high-throughput sequence annotation pipelines combine To decode the information contained within these sequences. The present ability to sequence almost entire genomes outpaces in some aspects current computational and experimental methods Genomes of additional eukaryotes, including the chimpanzee, zebrafish, and bumblebee, are slated for sequencing in the next Other eukaryotic genomic sequences, including those of the mouse and rat, will be completed in the near future, and the To whole-genome sequences for over 85 microbial organisms (see ) as well as a handful of eukaryotic species, including a yeast ( Saccharomyces cerevisiae), a nematode ( Caenorhabditis elegans), a fruitfly ( Drosophila melanogaster), thale cress ( Arabidopsis thanliana), a variety of rice ( Oryza sativa japonica), a pufferfish ( Fugu ribripes) and humans ( Homo sapiens). The biosciences community currently has access The remarkable accomplishments of the past decade in genomic biology were achieved in large part by significant technologicalĪdvances in DNA sequencing as well as data and information processing systems. In this review, we outline the strategy for choosing DNA sequences fromĭifferent species for comparative analyses and describe the methods used and the resources publicly available for these studies. Comparative analysis of DNA sequences from multiple speciesĪt varying evolutionary distances is a powerful approach for identifying coding and functional noncoding sequences, as wellĪs sequences that are unique for a given organism. With the availability of whole-genome sequences for an increasing number of species, we are now faced with the challenge ofĭecoding the information contained within these DNA sequences.

Nucleotide sequence comparison