Fast evolving 18S rRNA sequences from Solenogastres (Mollusca) resist standard PCR amplification and give new insights into mollusk substitution rate heterogeneity

Table 1 Sequence composition within selected taxa (no = number of specimens) characterized using the disparity index (I_D), compositional distance (Dc), percent GC content, gene length in base pairs (bp) and average branchlengths (brls) with standard deviation (σ).

Taxa	No	I _D	Dc	GC	bp	Brls*10	σ*10
Outgroup	41	0.42	0.52	48.5	1682.9	0.60	0.41
Polyplacophora	32	0.08	0.11	49.9	1739.8	0.46	0.08
Monoplacophora	1	n/c	n/c	50.4	1767.0	0.38	n/c
Scaphopoda	22	0.14	0.21	53.5	1835.8	1.47	0.19
Caudofoveata	3	0.00	0.01	55.8	1785.0	1.82	0.08
Solenogastres	3	0.18	0.23	63.9	2100.0	5.27	0.24
Cephalopoda
Coleoidea	74	0.19	0.28	60.3	2275.3	7.48	1.37
Nautiloidea	3	0.31	0.34	52.9	2360.0	5.40	0.35
Gastropoda
Vetigastropoda	31	0.03	0.08	51.2	1784.9	2.10	0.12
Neritimorpha	5	0.00	0.02	50.6	1736.0	0.43	0.05
Neomphalida	3	0.09	0.14	51.3	1790.7	1.48	0.02
Cocculinida	1	n/c	n/c	50.1	1749.0	4.11	n/c
Patellogastropoda	9	0.42	0.50	57.2	2011.9	5.99	0.05
Caenogastropda	116	0.01	0.02	50.7	1745.7	0.86	0.05
Heterobranchia	183	1.86	1.96	55.3	1796.5	2.18	1.54
Bivalvia
Protobranchia	18	0.12	0.17	50.6	1751.6	0.46	0.24
Paleoheterodonta	13	0.02	0.05	49.6	1750.5	0.47	0.08
Pteriomorpha	111	0.06	0.10	49.6	1742.1	0.48	0.38
Heterodonta (ex. Anom.)	160	0.25	0.34	52.2	1760.2	2.01	0.48
Anomalodesmata	41	0.11	0.20	51.7	1874.7	2.86	0.27

* Brls and σ values were multiplied with 10 for better readability. We used all sequences available for the Mollusca, Sipuncula and Kamptozoa with a length over 1,600 bp, supplemented by some other Lophotrochozoa and Priapulus caudatus.
Sequence composition of Mollusca within selected taxa measured using the disparity index (I_D), compositional distance (CD), GC content [%], gene length in base pairs (bp) and average branch lengths (brls) and their standard deviation (σ). Brls and σ values were multiplied with 10 for better readability. We used all sequences available for the Mollusca, Sipuncula and Kamptozoa above 1,600 bp supplemented by several other Lophotrochozoa and Priapulus caudatus.

ISSN: 2730-7182