Tests for selection acting on marker loci were carried out using the FST outlier approach [ 40, 41] and were performed with the lositan software package [ 42].
Groups of SNPs often hang around together, acting as markers for entire blocks of DNA.
The technique for material preparation using the FIB consisted of first milling two crosses alongside the indented area, acting as markers and then depositing a 1-μm thick layer of Pt to protect the area of interest from Ga+ion beam damage and implantation.
As to what could be the cause of the associations detected for these SNPs, a possibility is that they are acting as markers of some nearby elements.
Our sequencing was not exhaustive therefore it is possible that these SNPs do not represent the functional variants but are acting as markers for functional polymorphisms that were not identified by our sequencing.
Of the 20 discriminating genes originally reported, a proportion were predicted simply to be acting as markers and only some to directly influence Gc action.
Ambient PM2.5 is produced by numerous emission sources, and individual PM2.5 components identified as having associations with health outcomes may be acting as markers for other components or a set of components with similar sources.
In an observational study, it is not possible to determine whether associations are causal, and there is continuing debate regarding the possibility that early-life factors, such as breastfeeding duration, are acting as markers of the postnatal environment (35, 36).
It has been proposed that the associations of physical performance and strength with mortality rates and cardiovascular disease 2,3,35 may be explained by the fact that performance and strength are acting as markers of lifetime physical activity.
Physical capability levels in later life could also be acting as markers of exposure to risk factors across life, with those people with lower capability levels expected to have been exposed to more adverse risk factors across life and so at increased risk of poor health later in life.
