marker trait

mark·er trait

a trait that may be of little importance in itself but which by association, linkage, or other means facilitates the detection, anticipation, or understanding of a disease or (for genetic diseases) the localization of the causative gene on the karyotype.

mark·er trait

(mahr'kĕr trāt)
A trait that may be of little importance in itself but which by association, linkage, or other means facilitates the detection, anticipation, or understanding of a disease or (for genetic diseases) the localization of the causative gene on the karyotype.