Heritability complex traits

Since the first publication in 2005, GWAS studies have successfully identified hundred of genetic variants associated with complex diseases and important phenotypes. Despite the early success, most identified variants individually or in combination confer relatively small increments in risk and explain only a small proportion of heritability. For example, in the genetics analyses of height, a classic complex trait with an estimated heritability of 80 %, at least 40 loci showed significant association however, in total they only explain about 5 % of phenotypic variance in analyses of tens of thousands of people [103]. One possible contributor to the small genetic effect sizes observed so far is that researchers have incompletely... 

Taken as a whole, these observations show that parasite lines differ in an immune-dependent manner in their infection/expulsion kinetics. Furthermore, there is heritable variation in survival and fecundity in previously exposed hosts and quantitative variation in the immune response that selected parasite lines elicit. Again, taken as a whole, these observations have the necessary corollary that variation in these traits exists not only in laboratory-maintained isolates but also in helminth species in nature. The phenotypes under consideration here (infection/expulsion kinetics, survival, fecundity) are multifactorial life-history traits. Understanding the basis of variation in the components and interplay of these complex, immune-responsive phenotypes must be of crucial relevance to understanding the immunology of infections of parasitic nematodes. This is of particular relevance in view of current attempts to develop immunological methods of nematode control. 

While the heritability of flavor precursor accumulation in onions has not been determined, it is most likely a quantitatively inherited trait. As described earlier, the biosynthetic pathway is complex with many peptide intermediates. n addition, 11 proposed enzymes regulate compound synthesis in the flavor pathway U7). Further empirical evidence to support quantitative inheritance of the flavor... 

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