Becher & Griffiths (2008) Genetic differentiation among local populations of the European hedgehog in mosaic habitats
Title: Genetic differentiation among local populations of the European hedgehog (Erinaceus europaeus) in mosaic habitats, Molecular Ecology: Short Communication 7;1599-1604. 1998
Authors: S. A. Becher & R. Griffiths
Background to study
An investigation using neutral genetic markers (microsatellites) into the genetic variability and gene flow between small populations of hedgehogs in agricultural landscapes.
- 160 tissue samples were obtained by ear biopsies taken from hedgehogs captured during nightly spotlight surveys between May and September 1990-1993.
- Hedgehog samples were obtained from eight habitat patches of grassland around Oxford, where estimated hedgehog abundance ranged from 12 to 105 individuals.
- DNA was extracted from each sample using standard methods and six microsatellite markers (variable regions of neutral DNA) were isolated. Diversity indices including the number of alleles and proportion of heterozygotes (individuals with two alleles per loci that are not identical by descent) were calculated, as was the genetic structure between populations (using Rousset’s parameter RhoST).
- Gene flow (i.e. the number of migrants that are exchanging genes between populations) was calculated using the frequency of private alleles (genetic variants that are unique to a population) and the relationship between gene flow and distance was investigated using a mantel test which permutes between two matrices of genetic differentiation and geographic distance.
- Between six and nine alleles were identified across the six microsatellite markers and private alleles were observed in six of the eight samples.
- Significant heterozygote deficiencies were observed in one population which may suggest a loss of diversity due to inbreeding or naturally low levels of genetic diversity at the genetic markers analysed in this study.
- The populations were significantly structured genetically which suggests that gene flow is not sufficient to prevent populations becoming genetically dissimilar from each other.
- Gene flow estimates suggested that 2.34 individuals on average were exchanged between populations per generation, however this varied from 0.36 individuals between two populations separated by 16.75 km and 9.58 individuals between two populations separated by 10.75 km.
- There was no significant correlation between the genetic differentiation between populations and geographical distance suggesting that factors other than distance influence the rate of gene flow between populations.
Key messages to landowners and managers derived from these results
- Further investigation using neutral genetic markers is recommended to ascertain other factors that may influence the dispersal behaviour of hedgehogs and extent of genetic exchange between populations.
- Investigations into habitats that facilitate dispersal of hedgehogs between populations and that determine the threshold distance between populations that result in their isolation is highly recommended.