overexpression
/ˌəʊv(ə)rɪkˈsprɛʃn/ /ˌəʊv(ə)rɛkˈsprɛʃn/noun
1The excessive or exaggerated expression of feelings, an opinion, etc.
2 Genetics. The production of abnormally large amounts of a substance which is coded for by a particular gene or group of genes; the appearance in the phenotype to an abnormally high degree of a character or effect attributed to a particular gene.
Origin
Mid 19th century; earliest use found in The Spectator. From over- + expression.