Although multiple substitutions were previously thought to occur only for ancient divergences, variation in evolutionary rates across sites due to different functional constraints can produce multiple hits even for recent divergences [ 25- 27].
The ADOs from Synechocystis sp. PCC 6803 and Prochlorococcus marinus MIT9313, and the corresponding variant A134F displayed less divergence, although variation between chain-length preferences could be observed.
Mutation rates vary among chromosomes [39] and the human-chimpanzee genetic divergence shows variation between autosomes [40].
However, its vast geographical distribution accompanied by morphological differences suggests potential taxonomic divergence and variation in venom composition.
We analysed the relationship between amino acid sequence divergence and variation in GC3, to test the effect of evolutionary divergence on codon usage.
Patterns consistent with recent positive selection were also detected in TLR21 of L. v. graecus: an excess of divergence, low variation, and six replacement substitutions fixed by selection as inferred by gammamap.
Here, we have combined divergence and variation measures to identify genes containing adaptive substitutions in the human lineage, but not in chimpanzees or the common ancestor or both species.
This planned sequencing of Azolla will provide initial and much-needed genomic resources for ferns, but given the deep divergence times, variation in life-history characteristics, and diversity within this clade, one fern genome is simply not enough to address the full range of outstanding genomic questions in ferns and across land plants.
Although the species described here (especially O. coquereli, A. goodmani and A. boltoni) contain large CO1 divergences, such variation is always geographically segregated, as one might expect from a species where the queens (when known) are ergatoid.
