3.2 Genetic diversity, inbreeding and mean kinship
Measures of the mean number of alleles, effective number of alleles,
expected and observed heterozygosity and allelic richness were all lower
in the three King Island scrubtit subpopulations than they were within
all of the Tasmanian scrubtit subpopulations, except the Tasman
Peninsula (Table 1, Figure S10). FIS confidence
intervals overlapped zero in all subpopulations (Figure S10). Mean individual level
inbreeding coefficients calculated using the modified Visscher’s method
were higher in the three King Island scrubtit populations than all of
the Tasmanian scrubtit populations, again except the Tasman Peninsula
(Figure 5a). The majority of King Island scrubtits plotted towards the
higher end of individual inbreeding estimates across the entire sample
(Figure 5b). The mean number of private alleles within the King Island
scrubtit subpopulations were within the range of those of the Tasmanian
scrubtit, but the number increased three-to-sixfold when King Island
scrubtits were analysed separately (Table 1). Within population mean
kinships for the King Island populations when analysed as the island
populations only, reflected on average a first cousin relationship
(~0.0625; Table 1). However, when within population mean
kinships for King Island populations were analysed with all the
Tasmanian mainland populations, the within populations mean kinship for
the King Island populations reflected on average a full-sibling
relationship/parent-offspring (~0.2500; Table 1).
Samples from the Tasman Peninsula also reflected a mean kinship of a
full-sibling/parent-offspring relationship, whilst the North East and
South Bruny Island samples reflect a mean kinship of a half-sibling
relationship (Table 1).
Table 1: Sample sizes by molecular sex (F/M) and population
genetic parameters for the King Island and Tasmanian scrubtit.
Parameters shown are number of alleles (A), number of effective alleles
(AE), SNP expected heterozygosity (HE),
SNP observed heterozygosity (HO), Wright’s inbreeding
coefficient (FIS ± 95 % CI), mean individual inbreeding
coefficient (IIC), allelic richness
(AR), mean private alleles (PA) and within population
mean kinship (mean ± SE) for King Island populations only, and for all
subpopulations. See Table S6 for estimates with standard errors.