trihybrid

An organism that is heterozygous for three genes, e.g. AaBbCc. Trihybrid crosses, especially of the type AaBbCc x aabbcc, are commonly used devices in chromosome mapping. By comparing the frequencies of the phenotypes, the chromosomal arrangements of the three genes A/a, B/b, and C/c can be deduced. This is technically easier than setting up three dihybrid crosses AaBb x aabb, AaCc x aacc, and BbCc x bbcc, which would only achieve the same result.