Position effect is referred to the effect on gene expression when the gene is translocated from the location it is on a chromosome to another location.
As it relates to gene silencing and euchromatic gene repositioning, Position effect variegation best explains it.
Position effect variegation occurs when a gene in some cells is silenced as a result of rearrangement of chromosomes which translocate or reposition euchromatic genes close to vicinity of heterochomatin. It is this abnormal chromosomal juxtaposition that leads to the gene silencing in stochastic pattern.
