The effects on gene expression that depend on the location of a gene with respect to its neighboring genes and region of chromosome. Stable position effects are sequence dependent. Variegated position effects depend on whether the gene is located in or adjacent to HETEROCHROMATIN or EUCHROMATIN.
Eye Color
Color of the iris.
Chromosome Mapping
Any method used for determining the location of and relative distances between genes on a chromosome.
Chromosomes
In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)
Transgenes
Genes that are introduced into an organism using GENE TRANSFER TECHNIQUES.