Maximum likelihood tree of published spidroin C-termini and homologous black widow unique assembled transcripts (UATs). The C-terminal regions of known L. hesperus (Lh) spidroins are shown in orange, other known spidroins are shown in grey, and translated UATs are black. Accession numbers for published spidroins are in [33, 44]. The tree is midpoint rooted and all bootstrap values greater than 50 are shown. Expression rank and FPKM (fragments per thousand base pairs per million mapped fragments) are shown on the right. Rank is based on FPKM in the silk glands out of all UATs expressed in silk glands. Clades corresponding to different gland specific expression are in colored rectangles.