Jonestype2

Jonestype2 is a fictional haplotype used in theoretical population genetics and computational simulations to illustrate how multi-locus haplotypes can change in frequency under the combined forces of natural selection, recombination, and migration. The term appears in instructional materials and thought experiments as a canonical example rather than a discovered allele in a real population. It is commonly paired with Jonestype1 to contrast simpler ancestral haplotypes with a derived two-locus variant.

In the Jonestype2 framework, the haplotype is defined by a specific two-locus combination, typically denoted as A1 at locus A and B1 at locus B, resulting in the JT2 haplotype. Fitness effects are assigned selectively; under certain environmental conditions, individuals carrying Jonestype2 may experience a relative fitness advantage, while in other contexts the advantage may be neutral or negative. The model also incorporates recombination rate r between the two loci, which can create or break apart JT2, and migration rate m that introduces JT2 into or withdraws it from subpopulations. The dynamics of JT2 are often explored through simulations and differential equations to demonstrate linkage disequilibrium, hitchhiking, and the balance between selection and gene flow.

See also: haplotype, population genetics, linkage disequilibrium, selection, recombination.