We are based in the Department of Biology at Duke University. Evolutionary trees allow us to identify the members of a gene family, which can aid in the functional prediction of an orthologue.
Many genes belong to multigene families.
Within the vertebrates, nearly all loci are part of multigene families, due to apparently genome-wide duplications during the early evolutionary history of the group. Individual gene duplications and losses occur within all eukaryotic organisms, and there is no way to know ahead of time when to expect such events. The most basic difficulty is know knowing which member of a gene family you are studying. This information is essential if you wish to utilize data on genes from other species, compare your results to those obtained from another species, or to identify evolutionarily conserved structural features as a clue to function. Second, particular patterns of nucleotide substituion can lead to superficially similar sequences.