Table 1 Glossary
From: The population genetics of parasitic nematodes of wild animals
Term | Definition |
|---|---|
Census size (N) | The number of individuals in a population |
Effective population size (Ne) | Effective population size (Ne): The number of individuals needed in an idealised population to explain the rate of change in allele frequency, or to explain the observed degree of inbreeding, observed in a real population [180] |
Environmental DNA (eDNA) | DNA released by organisms into the environment [174] |
Fixation | When only a single allele remains at a formerly-polymorphic locus |
Gene flow | Movement of alleles among populations [181]. Tends to reduce genetic differentiation |
Genetic drift | Stochastic change in allele frequencies within a population across generations [180]. Tends to increase genetic differentiation |
Hardy-Weinberg equilibrium | The situation in which the number of heterozygotes observed matches the number of heterozygotes expected given the allele frequencies in the population [182] |
Idealised population | A theoretical population in which each individual produces an infinite number of gametes, any gamete may fuse with any other of the opposite sex with equal probability, sex ratios are even, and there is no overlap in generations [180] |
Infrapopulation | All the parasites of one species within one host individual [21] |
Isozymes | Different, usually allelic, forms of an enzyme, which can be detected by differences in electrophoretic charge [183] |
Linkage disequilibrium | The joint inheritance of particular alleles at different loci more often than would be expected by chance, usually due to their close physical proximity on a chromosome [184] |
Phylogeography | Historical drivers of the current geographical distribution of a species [185] |
Polymorphic | Sequence variation at a locus, classically with multiple alleles present at frequencies of 5% or greater [186] |
Population (of a parasite) | A group of parasite infrapopulations that may exchange individuals freely [21] |
Population bottleneck | Loss of a large, random portion of the population, resulting in reduced genetic diversity |
Random amplified polymorphic DNA (RAPD) | DNA fragments amplified by a defined set of arbitrary PCR primers, polymorphic due to inter-individual differences in primer binding sites [187] |
Ribosomal internal transcribed spacers (ITS) | Putatively non-functional stretches of DNA between the ribosomal RNA-encoding genes in eukaryotes. [188]. The first and second ITS are denoted ITS1 and ITS2 respectively |
Selective sweep | An increase in the frequency of a set of alleles owing to their genetic linkage to an allele undergoing positive selection [189] |