Discrete processes of positive selection will have occurred in different species lineages, against a background of selective constraint that varies among genes in a manner that is apparently more homogeneous between different lineages.
This is consistent with historical purifying selection in both lineages against P->U changes.
The linearity for the relationship of log(number of lineages) against time can be visually inspected with a Lineage Through Time plot [ 131, 132].
Each newborn individual inherits maternal antibodies against all influenza strains or lineages against which his or her mother is immune at the time of birth; maternal antibodies protect the newborn individual against infection for some months.
Nonparametric Mantel tests for isolation as a function of environment were conducted using 9999 permutations of pairwise matrices of FST (within lineages) against absolute pairwise difference in values for environmental variables.
At the core of these discussions is the recognition of species as segments of population lineages against a view of species as operational units of a taxonomic rank [ 11].
As cell cultures in vitro have been widely used in experimentation, and are emerging for high-impact applications spanning from routine toxicological screenings to formulating artificial organs, it is essential to validate cultured cells (and lineages) against freshly isolated cells.
At the time, this was hypothesised to be an outbreak caused by a single strain, but we show that it was in fact two outbreaks triggered by two distantly related MDR K. pneumoniae lineages against a complex backdrop of sporadic endemic K. pneumoniae infections.
That a convincing Tree of Life cannot be recovered from molecular sequences should come as no surprise, nor should the fact that shallower relationships can indeed be interpreted to some extent as cohesive lineages against which ecological and phylogenetic hypotheses can be tested.
