Biology Reference
In-Depth Information
The Jirel data were further analyzed upon completion of the geno-
typing for all 1258 individuals.
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This new analysis resulted in the local-
ization of three significant quantitative trait loci. The linkage to
chromosomal region 13q33 remained in the larger sample, confirming
that TNFSF13B is likely involved in determining risk for Ascaris infection.
The LOD score plot for this QTL is shown in
Figure 12.1
. The peak
observed LOD was 3.37 occurring at 113 cM with a 1-LOD support
interval extending from 104 to 117 cM. The genome-wide (corrected for
multiple testing) p-value was 0.013. There is an additional significant
linkage to chromosomal
region 11p14 (LOD
¼
3.19, genome-wide
p
0.020) which encompasses 54 known genes in the QTL support
interval. A potential candidate in this area is CD59 which is a membrane-
bound inhibitor of the cytolytic membrane attack complex (MAC) of
complement.
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The third significant QTL linked to Ascaris egg counts was
found at chromosomal region 8q23 in a region encompassing over 300
known or predicted genes. Two possible candidate genes were suggested
for this region: first, a gene thought to be involved in mediation of viral
infection, MAL2
50
; and second, a member of the collectin family which is
involved in innate immunity, COLEC10.
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¼
FIGURE 12.1
Quantitative trait linkage analysis results showing a major QTL influ-
encing Ascaris burden on chromosome 13 in the Jirel population.
