VNTR LOCI REVEAL DIFFERENTIATION BETWEEN AND STRUCTURE WITHIN POPULATIONS OF THE EASTERN BARRED BANDICOOT PERAMELES-GUNNII

The Eastern Barred Bandicoot Perameles gunnii has declined in abundanc e within mainland south-eastern Australia, to a relict wild population of less than 100 individuals in Hamilton, Victoria. It is more common , but is also declining in Tasmania. Genomic DNA variability was compa red within and between surviving populations of P. gunnii using variab le number of tandem repeat (VNTR) markers in one of two ways. First, a verage percentage differences (APDs) were determined between profiles for two VNTR probe-endonuclease combinations. Secondly, because one of these combinations revealed two multiallelic VNTR loci, genotypes wer e assigned and analysed for homogeneity of allele frequencies among su bpopulations, for deviation of heterozygosity from Hardy-Weinberg equi librium within populations and for genetic structuring among individua ls from different subpopulations. The results of both the APD and defi ned locus approaches showed consistent trends within and between popul ations. Genetic variability was higher among mainland P. gunnii than i n Tasmanian populations (higher APDs, number of alleles, and heterozyg osity at one locus), despite the known decline and subdivision of the Hamilton population. Eleven per cent of the variability detected in Ha milton was attributed to genetic differentiation between east and west subdivisions of the population. Departure from random mating indicati ng local inbreeding within collecting localities was evident for one l ocus in both north and south Tasmania, particularly at one locality. A ll alleles at both loci were unique to either Hamilton or Tasmanian P. gunnii. The initial captive colony contains high heterozygosity for t hese loci. It is concluded that VNTR markers can be of benefit for use in studies of population differentiation and for conservation managem ent.