Phylogram of Spp and SppL ortholog sequences.

<p>Sequences are marked with an abbreviation for the species (i.e., <i>D. melanogaster</i> SppL, Dmel-SppL; see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033827#pone-0033827-t001" target="_blank">Table 1</a> for a list of species); accession identifiers for each sequence are in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033827#pone-0033827-t001" target="_blank">Table 1</a> or in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033827#s2" target="_blank">METHODS</a>. The magenta box groups the <i>Drosophila</i> Spp orthologs; light pink, other insect Spp orthologs; white, human SPP, SPPL2a, SPPL2b, SPPL2c, SPPL3; blue, <i>Drosophila</i> SppL orthologs; and light blue, other insect SppL orthologs. SppL proteins are more closely related to human SPPL3 than to SPP or SPPL2a, b, or c; and the SppL sequences retain a higher interspecies conservation than Spp sequences. (The apparently truncated sequence of the <i>D. virilis</i> SppL ortholog is not included in this analysis.).