LOSS OF GENETIC DIVERSITY AND FITNESS IN COMMON TOAD (BUFO-BUFO) POPULATIONS ISOLATED BY INIMICAL HABITAT

Citation
Sp. Hitchings et Tjc. Beebee, LOSS OF GENETIC DIVERSITY AND FITNESS IN COMMON TOAD (BUFO-BUFO) POPULATIONS ISOLATED BY INIMICAL HABITAT, Journal of evolutionary biology, 11(3), 1998, pp. 269-283
Citations number
40
Categorie Soggetti
Ecology,"Genetics & Heredity","Biology Miscellaneous",Biology
ISSN journal
1010061X
Volume
11
Issue
3
Year of publication
1998
Pages
269 - 283
Database
ISI
SICI code
1010-061X(1998)11:3<269:LOGDAF>2.0.ZU;2-H
Abstract
Measures of genetic diversity (including heterozygosity), survival and developmental homeostasis were found to be significantly lower in sma ll, urban populations of the Common Toad (Bufo bufo) than in larger, r ural populations of the same region. The autecology and genetic analys is of this relatively sedentary species suggested that the causal mech anism was genetic drift, arising from barriers to migration created by urban development. The pre-metamorphic survival of larvae cultured in identical conditions increased positively with the mean number of all eles at a locus and the percentage of polymorphic loci. Observed heter ozygosity in urban garden and rural populations was correlated inverse ly with the number of observed physical abnormalities (used as st meas ure of developmental homeostasis) in the developing tadpoles. Genetic distances between town sites of mean 2.2 km separation were significan tly higher than those between rural sites of mean 37 km separation. Ge netic data were based on allozyme analysis of 27 loci in 8 urban and 4 rural populations. A subset of these sites (3 urban, 2 rural) were al so assessed at 3 minisatellite loci and a positive correlation found b etween the average number of alleles per locus detected by the two met hods. Estimates of Nei's 1972 genetic distance, derived separately fro m the DNA and protein data, were not, however, correlated. The reducti on in genetic diversity and fitness observed in these urban toads prov ides an example of the effect on population persistence that longer te rm depletion in numbers and habitat fragmentation can have in the wide r environment.