Ortoloogi

Ortoloogi is a term used in Estonian to refer to the study of orthology in biology, or more generally to the professionals who work in this field. In molecular biology, orthology describes the relationship between genes in different species that originated by a speciation event. Orthologous genes, or orthologs, often retain similar functions across species, though this is not guaranteed. They are contrasted with paralogs, which arise by gene duplication within a single species. Studying orthology helps researchers infer gene function in less well-characterized organisms by leveraging information from model species and to understand how genomes evolve over time.

History and scope: The formal concept of orthology emerged in the late 20th century and has become a central pillar of comparative genomics and phylogenomics. Orthology is typically inferred from sequence similarity, phylogenetic analyses, or reciprocal best-hit approaches, and is implemented in specialized databases and software tools.

Applications: Practical uses include transferring functional annotations between species, annotating newly sequenced genomes, and reconstructing evolutionary histories of gene families. Orthology analysis supports comparative studies of gene repertoires across taxa and informs studies of conserved versus lineage-specific functions.

Tools and resources: Common methods and platforms include OrthoFinder, OrthoMCL, eggNOG, and OrthoDB, which provide curated sets of orthologous genes across multiple species. Researchers must account for complications such as gene duplications, loss, horizontal transfer, and varying evolutionary rates when interpreting orthology results.

See also: Comparative genomics, paralogy, phylogenomics, genome annotation.

Note: In everyday Estonian usage, ortoloogi may also refer informally to a professional working in this domain.