Bidirectional best hits

Bidirectional Best Hits is a method of bioinformatics to orthologous genes to identify.

Action

In order to find an orthologous gene for a given gene in the organism , a blast search is first carried out in the entire genome of the organism for the gene . The result is a list of sequence alignments sorted according to the quality of the hits. ${\displaystyle A_{x}}$ ${\displaystyle B}$ ${\displaystyle B}$ ${\displaystyle A_{x}}$

In order to identify the bidirectional best hits, the hit (i.e. the sequence from the organism ) is now used to perform a search in the entire genome of the organism (i.e. the original organism ). The best hit should now be the original gene. If so, the two genes are BBHs. ${\displaystyle B}$ ${\displaystyle A}$ ${\displaystyle A_{x}}$

BBHs are very similar to each other. It is believed that they are orthologues.

These methods can be carried out both with protein sequences and with nucleotide sequences.

criticism

This procedure is based on the assumption that no two genes are more similar than two orthologues. This assumption may be true in most cases, but certainly not always.

literature

• Ross Overbeek et al .: The use of gene clusters to infer functional coupling . In: PNAS . tape 96 , no. 6 , March 1999, PMC 15866 (free full text).

Web links

• "BBH" at the National Microbial Pathogen Data Resource (USA)