ORTHOLOG--CONCEPT,BIOINFORMATIC INFERENCES AND DATABASES
ortholog ——— 概念、生物信息预测方法和数据库

Orthologs are genes in different species that originate from a single gene in the last common ancestor of these species. Orthologous genes are suggested to share similar functions,be regulated by similar biochemical pathways and play similar roles in different species. Thus, it is the best choice to use orthologous genes when annotating newly discovered genes. There are mainly two categories of algorithms for predictions of orthologs: phylogenetic algorithms and sequence comparison algorithms. Both of them are based on sequence similarities, whereas they have their own characteristics. Phylogenetic ways predict orthologs by reconstructing phylogenetic trees. As a result, they are conceptually accurate, but hard to automate, and demanding huge amount of computational resources. In contrast, the latter methods are conceptually less accurate but not as complex and require less computational resources, therefore, widely used.