Gene Flow
Definition
The movement of alleles between populations through migration and reproduction. High gene flow homogenises populations; low gene flow allows them to differentiate genetically over time.
- Definition
- Movement of alleles between populations via migration and reproduction
- High gene flow effect
- Homogenises populations genetically
- Low gene flow effect
- Allows populations to differentiate over time
Common questions
Why does gene flow matter when using insects to estimate a body's geographic origin or movement?+
Populations of a species with low gene flow between regions can carry distinguishable genetic signatures, so matching an insect specimen's genetic profile to a regional population can help indicate where a body or item originated or travelled from, while high gene flow between regions weakens that regional signal.
How does gene flow differ from genetic drift as a force shaping population genetics?+
Gene flow moves alleles between populations through migration and interbreeding, actively counteracting differentiation, while genetic drift is random change in allele frequency within an isolated population over generations; low gene flow allows drift's effects to accumulate and populations to diverge.
What limits the precision of gene-flow-based geographic assignment in casework?+
Human-assisted transport of insects, overlapping regional populations, and incomplete reference databases for regional genetic variation all reduce the confidence with which a specimen can be assigned to a specific geographic origin using gene flow patterns alone.
Related terms
- Body Movement Inference
- The forensic application: using the population-genetic signature of insects collected from a body to estimate where colonisation occurred, and therefore potentially where...
- Genetic Structure
- The degree to which populations within a species are genetically differentiated from each other. Measured by statistics like Fst (fixation index). High...
- Haplotype
- A specific set of genetic variants inherited together, typically used here for mitochondrial DNA variants. Different geographic populations of the same species...
- Phylogeography
- The study of the geographic distribution of genetic lineages within and among closely related species. Provides the reference maps that forensic population...
- Reference Population Panel
- A georeferenced dataset of sequences from known collection localities, used as the comparison baseline when the provenance of a forensic specimen is...