genetic marker a gene having alleles that are all expressed in the phenotype, that is, they are codominant, and which can be used to study inheritance. The various blood group systems and serum or red blood cell proteins easily detected by electrophoresis or immunodiffusion are commonly used markers.
Snowshoe has several commercial areas, with the most prominent being The Village at Snowshoe, located at the summit of the mountain (rather than at its base).
Very few living members of the Night's Watch have traveled as far north as the Fist, and fewer still beyond it. Hardhome is an abandoned town located north-east of the Wall. Hundreds of years before the events of Game of Thrones, Hardhome was the only real settlement north of the Wall. A sudden and mysterious event resulted in the complete depopulation of the town though, and it has been considered cursed ever since.