There are two broad reasons why a trait of interest (in this case vector-transmission) might not evolve.
In many cases a trait of interest cannot be reliably tracked by a single SNP.
Because it conflates the notions of design and function, it becomes necessary to mark the distinction between cases of selection with modification (function/design) and cases where a trait of an organism is coopted for a use for which it is not modified (exaptation).
The alternative, called a soft sweep, is that many genes influence a trait, in this case the rate of maturation, and that the growth-accelerating versions of each of these genes become just a little more common.
Indeed, a trait, in this case, the activity of the transferred gene that mediates antibiotic resistance, is acquired under a direct influence of the environment and is clearly advantageous, even essential in this particular niche.
Unlike previous studies, we have not investigated association of SNPs with BMI as a quantitative trait in cases of T2D [ Frayling et al., 2007; Timpson et al., 2009].
Gene cloning and especially cloning genes underlying QTL can provide a deeper molecular understanding of a trait and in the case of breeding, markers linked directly with the causative DNA mutation/changes.
Examination of a single trait shared by cases of a disorder (e.g., impaired social cognition in ASD) reduces outcome heterogeneity and may allow for identification of a more specific exposure-related biologic pathway.
Achondroplasia is inherited as an autosomal dominant trait; about 80 percent of cases of the disorder result from new genetic mutations rather than from the parental transmission of defective genes.
A high number of ASDs are hereditary cases [2], and there is mounting evidence that childhood cancer has likewise a higher fraction of cases with genetic traits than previously expected [3].
In order to track cumulative increases in complexity in the population, each trait xs is assigned a "trait fitness" of zx which describes that trait's effectiveness (in the case of technological inventions) or veracity (in the case of scientific theories).
