Where does marker collide?

In sociology a marker is an observable sign that signals a person's social standing, group membership, or identity to other people. Goffman's 1951 Symbols of Class Status analysed how possessions, manners, and speech serve as status symbols that people use to place one another in a social order, and how such signs can be borrowed or misread. Barth's 1969 Ethnic Groups and Boundaries extended the idea to identity markers such as dress, language, and custom that keep one community distinct from another. The referent is a social cue read by other people, not a morpheme in a sentence, a spot on a chromosome, or a layer of rock in the ground.[1][2]

Unit

One observable sign that others read as indicating status or group membership

Recovery means

Not applicable

Measured by

Studied through observation, interviews, and surveys of how people display and interpret such signs

In molecular biology and genetics a marker is a gene or DNA sequence with a known chromosomal location whose variation can be followed through inheritance and used to locate nearby genes. Botstein, White, Skolnick, and Davis's 1980 Construction of a genetic linkage map in man using restriction fragment length polymorphisms showed how naturally varying DNA sequences could serve as a dense set of such markers for mapping the human genome. Using a heritable trait as a marker predates this work in classical linkage genetics, but the 1980 paper established the DNA marker that underlies modern mapping. The referent is a measurable biological indicator sitting on a chromosome, not a grammatical form, a social sign, or a bed of rock.[3]

Unit

One heritable locus or DNA variant used to track inheritance

Recovery means

Not applicable

Measured by

Detected by genotyping methods such as restriction fragment analysis, PCR, or sequencing

In geology and stratigraphy a marker bed, or marker horizon, is a thin, distinctive rock layer that formed over a geologically brief span and can be recognised across widely separated locations, so it ties those sequences to the same moment in time. Alvarez, Alvarez, Asaro, and Michel's 1980 Extraterrestrial Cause for the Cretaceous-Tertiary Extinction identified a worldwide iridium-rich layer that acts as such a marker at the boundary between two geological periods. The Glossary of Geology (Neuendorf, Mehl, and Jackson, 2005) defines the marker bed as a unit of distinctive composition that permits correlation of strata across separate areas. The referent is a physical layer in the rock record used to correlate and date, not a morpheme, a chromosomal locus, or a social sign.[4][5]

Unit

One distinctive stratigraphic layer traceable across locations

Recovery means

Not applicable

Measured by

Correlated by field mapping and identified through composition, fossils, or geochemistry such as an iridium anomaly