Although only numerous publications are concerned with QTL detection in tilapia (Palti et al., 2002; Shirak et al., 2002; Streelman and Kocher, 2002), several studies have indicated that linkage group LG23 contains loci-affecting fitness traits. The results of this and several other unrelated studies in different tilapia species identified linkage group 23 of the tilapia genome as an interesting and promising chromosomal segment for QTL detection and fine mapping of traits with biological and economical interest.
However, since tilapia has 22 chromosomes and the current genome maps still have more linkage groups than chromosomes, LG23 is not a permanent number.
Indeed, the latest updated tilapia map published on the Hubbard Center for Genome Studies’ web site (http://hcgs.unh.edu/comp/) lists this linkage group as LG9.