The phenotype often remains stable in spite of extensive variation in the genetic material [ 1, 2].
Because of the extensive variation within each of the taxa studied (Fig. 3), despite being collected within a relatively small area (Table 1), taxon-wise predictions about germination, as fractions, are not possible.
Because of the extensive variation among avian lineages in the number of Class I genes [for example, [ 34, 44, 65]], it remains unclear what the ancestral condition for Class I genes might be.
If an organism in a community has sequenced relatives only at higher taxonomic ranks, such as class, then classification to a more precise rank will be impossible, and even assignment to the correct phylum will be difficult because of the extensive variation in DNA residue composition and gene content within most phyla (Brady and Salzberg, 2009; Parks et al., 2011; Perry and Beiko, 2010).
The lateral line sensory system of aquatic vertebrates is a promising model for genetic investigations of sensory evolution because there is extensive variation within and between species, and this variation is easily quantified.
Because the extensive variation in substitution rates in the Geraniaceae is restricted to the mitochondrial genome and because nonsynonymous rates are proportionately less elevated than synonymous rates (Fig. 2, Additional File 1), the root cause of this rate variation is almost certainly changes in the mitochondrial mutation rate.
These results indicate that the number of T2R genes shows extensive variation among taxa.
First, trans variation may be relatively more deleterious than cis variation, potentially because of extensive pleiotropy (Brem et al. 2002; Yvert et al. 2003; Denver et al. 2005; Prud'homme et al. 2007; Wittkopp et al. 2008b; Gruber et al. 2012).
At nucleotide level, a notable characteristic of HADH2 genes was the extensive variation in GC3 content.
