A possible explanation for the selection of initial and mean EVLWi as significant variables associated with prognosis may be an effect of the inclusion criteria used in those previous studies [12],[14],[16],[21], where ARDS was diagnosed on the basis of the AECC criteria [37].
The likely explanation for the selection and maintenance of this strategy by CD8+ (and as our preliminary analysis suggests CD4+) T lymphocytes is the need to rapidly generate a large cohort of effector T cells directed to an invading pathogen from a very limited number of naïve pathogen-specific T cell precursors.
The most plausible explanation for the selection of such a large, ambiguous list is a lack of detailed information about the source of cDNA libraries, with the result that more general terms from higher up the ontology hierarchy are often used for annotation of the gene.
A possible explanation for the selection of initial and mean EVLWi as significant variables associated with prognosis may be an effect of the inclusion criteria used in those previous studies [ 12],[ 14],[ 16],[ 21], where ARDS was diagnosed on the basis of the AECC criteria [ 37].
It should be mentioned, though, that caution should be taken when considering sexual selection as a sole explanation for the positive selection here found, because fru also codes for non-sex-specific transcripts [ 12], so it is possible that the signal of adaptive selection may be the result of selection over phenotypes not related to sexual behavior.
Another potential explanation for the balancing selection between sexes on the Z-chromosomal loci is a form of frequency-dependence selection.
Thus, a possible explanation for the positive selection found in these OGCs is that these genes are subject to the relaxed constraints of purifying selection, and positive selection has helped them to fit the beneficial variants.
