sterol: any of a group of natural steroid alcohols derived from plants or animals; they are waxy insoluble substances
steroid: any of several fat-soluble organic compounds having as a basis 17 carbon atoms in four rings; many have important physiological effects
linkage: (genetics) traits that tend to be inherited together as a consequence of an association between their genes; all of the genes of a given chromosome are linked (where one goes they all go)