Next, by means of statistical transformation of the homozygosity weighted by loci index, we determine how heterozygosity contributes to population growth in Soay sheep by modelling individual contributions to population growth (pt(i)) as a function of several covariates, including sex, weight and faecal egg count – a surrogate of parasitic nematode burden in the gut.
Although the 3′-most coding region tag of MaSp1 is identical among all three loci (Index 0, Figure 3), the sequences of downstream tags are unique and can therefore be used to compare locus-specific expression levels.
Loci 1 and 3 share an observed tag 144 bases downstream of the stop codon that is not found in locus 2 (Index 1, Figure 3; mean cpm in MA glands = 1063).
Interestingly, high sub-ST strain resolution was obtained at the spa locus (discriminatory index of 0.957), and 11 (26.83%) of the 41 spa types identified contained persistent and intermittent carrier strains exhibiting identical X domain repeats.
For example, in the BIN1 locus, the index SNP (rs744373) influences the level of DNA methylation at 13 CpGs, 25% of the probes in the BIN1 region, suggesting that the SNP has a large effect on the methylation status of the region.
We computed three common estimates of individual multilocus heterozygosity, using 'Rhh' R package (Alho et al. 2010): the standardized heterozygosity stH (Coltman et al. 1999), the internal relatedness Ir (Amos et al. 2001) and the homozygosity by locus Hl index (Aparicio et al. 2006).
PopGen32 (Yeh et al. 1997) was used for the population-based approach using F statistics, gene diversity over loci, proportion of polymorphic loci, Shannon index and gene frequency (Nei 1987; McDermott and McDonald 1993).
Third, we examine how individual heterozygosity, estimated using the normalised homozygosity weighted by loci (HL) index, contributes to population growth in the unmanaged population of Soay sheep (Ovis aries L). in St Kilda, Scotland.
Using a statistical transformation of the homozygosity weighted by loci (HL) index, we show that the relative importance of heterozygosity in Soay sheep population growth differs markedly between sexes and age-classes.
To test for multilocus linkage disequilibrium (i.e. non random association) among the 7 MLST loci the index of association IA and the slightly modified statistic rBard were computed using the Multilocus version 1.3 software [54].
