Biology Reference
In-Depth Information
We used the exact same standard Sanger-style sequencing procedures and
primer designs as detailed in Fenstad et al.
53
Two kb of the proximal
promoter (upstream of the translation start site) and all six exons (trans-
lated or untranslated) of the 13q QTL candidate gene, TNFSF13B
(NM_006573.3) were sequenced. We found 13 variants as a result of this
sequencing. The linkage disequilibrium plot detailing the squared
correlations among these variants is shown in
Figure 12.3
. In this plot,
dark red blocks document variants that are in high linkage disequilibrium
with one another and are, therefore, redundant. Variants that show little
correlation with other variants (such as rs60972017) are effectively inde-
pendent. When we performed association analysis using these 13 vari-
ants, only the G17226A variant in intron 3 was significantly correlated
with Ascaris egg count (p
ΒΌ
0.0357).
FIGURE 12.3
Observed linkage disequilibrium (measured by the squared correlation
coefficient between genotypes) in the chromosome 13 Ascaris burden positional candidate
gene, TNFSF13B, in 200 unrelated individuals of the Jirel ethnic group.
