Genes or proteins found in different species that are so similar in their nucleotide or amino acid sequences that they are assumed to have originated from a single ancestral gene. The beta globin chain genes in humans and chimpanzees would be examples of orthologs. If one compares the genome of Saccaromyces cerevisiae (q.v.) and Caenorhabditis elegans (q.v.), most orthologs have “core functions.” That is, they generate the proteins used in intermediary metabolism, DNA-, RNA-, and protein- metabolism, transport, secretion, and cytoskeletal structures. In contrast, the genes from C. elegans that function in intercellular signaling and gene regulation are not found in the yeast genome. See Chronology, 1975, King and Wilson; hemoglobin genes, Hox genes, Pan; contrast with paralogs.
Subjects: Genetics and Genomics — Chemistry.