Population assignment
Definition
A genetic method that compares a specimen's microsatellite or SNP profile to reference databases of known-origin individuals, assigning the specimen to the population it most probably belongs to. Used for ivory, rhino horn, and traded timber provenance.
- Primary markers
- Microsatellites and SNP profiles
- Common applications
- Ivory, rhino horn, and timber provenance in wildlife crime
- Method type
- Statistical comparison against reference databases
Common questions
What does population assignment tell you about a specimen?+
Population assignment tells you which geographic population a specimen most likely came from. Forensic scientists use genetic markers like microsatellites or SNPs to compare the specimen's profile against reference databases of known-origin materials, then calculate which population it matches best. It's particularly useful for wildlife products like ivory and rhino horn.
How does the statistical comparison work?+
The method compares your specimen's genetic or isotope profile to multiple reference populations and calculates the likelihood it originated from each one. The population with the highest likelihood becomes the assignment. This approach works because populations have distinct genetic signatures that reflect their geographic isolation and evolutionary history.
What types of evidence can population assignment use?+
The method works with genetic data (microsatellites and SNP profiles) as well as isotope profiles. Both types create distinctive signatures tied to a specimen's origin. This makes it flexible enough to handle ivory, rhino horn, timber, and other traded wildlife products where knowing geographic source matters for law enforcement.
Related terms
- Chloroplast microsatellite (cpSSR)
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- ICP-MS
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- Isoscape
- A map of isotope ratio variation across a geographic area, derived from systematic sampling of soil, water, plant, or mineral material; used...
- Lines of arrested growth (LAGs)
- Alternating dense and loose concentric rings in bone cortex visible in histological cross-section, analogous to tree rings. Each LAG marks a period...
- Radiocarbon dating (C-14)
- Age determination from the ratio of radioactive carbon-14 to stable carbon-12 in organic material. Atmospheric C-14 spiked during nuclear testing (1950s-1960s), allowing...
- Skeletochronology
- Age estimation from growth rings (lines of arrested growth, LAGs) in bone cross-sections. Reliable in reptiles and fish; less so in mammals....
- Stable isotope analysis
- Measurement of the ratios of stable isotopes (typically strontium-87/86, oxygen-18/16, carbon-13/12) in tissue. These ratios reflect local geology, hydrology, and diet, providing...
- Stable isotope ratio
- The ratio of a heavy to a light stable (non-radioactive) isotope of an element, expressed as delta (delta) in per-mil notation relative...
- Swietenia
- The mahogany genus (S. macrophylla, S. mahagoni, S. humilis), listed on CITES Appendix II. The subject of well-developed cpSSR population genetic reference...
- Tusk weight-age curve
- A species- and sex-specific regression of tusk mass against age, derived from known-age wild elephant records. Allows investigators to estimate the age...
Explained in these topics
- Ageing, Sexing, and Geographic Provenance of SpecimensA genetic method that compares a specimen's microsatellite or SNP profile to reference databases of known-origin individuals, assigning the specimen to the pop...
- DNA and Isotope Methods for TimberA statistical procedure that compares a specimen's genetic or isotope profile to reference populations and calculates the likelihood that the specimen originat...