Table 1.

Relative lengths (RL), centromeric indices (CI) and classification (C) of mussel chromosomes

	Mytilus edulis			Mytilus galloprovincialis			Mytilus trossulus			Mytilus californianus
Pair	RL	CI	C	RL	CI	C	RL	CI	C	RL	CI	C
1	9.21 ± 0.29	43.56 ± 0.91	m	9.31 ± 0.35	44.50 ± 1.19	m	9.41 ± 0.23	45.67 ± 0.82	m	9.66 ± 0.40	36.40 ± 0.70	sm
2	8.20 ± 0.25	38.68 ± 0.72	m/sm	8.08 ± 0.17	39.82 ± 0.86	m	8.09 ± 0.24	31.53 ± 1.45	sm	8.52 ± 0.27	34.89 ± 0.95	sm
3	8.05 ± 0.24	20.48 ± 0.90	st	7.91 ± 0.22	27.57 ± 0.91	sm	7.74 ± 0.19	27.95 ± 1.15	sm	8.00 ± 0.25	24.95 ± 0.94	st/sm
4	7.57 ± 0.28	25.35 ± 0.85	sm/st	7.42 ± 0.14	25.96 ± 1.14	sm/st	7.69 ± 0.22	45.48 ± 0.62	m	7.84 ± 0.19	45.63 ± 0.59	m
5	7.41 ± 0.29	45.08 ± 1.07	m	7.26 ± 0.19	46.31 ± 1.16	m	7.43 ± 0.17	45.52 ± 0.75	m	7.76 ± 0.12	41.67 ± 1.10	m
6	7.27 ± 0.19	44.20 ± 0.99	m	7,24 ± 0,18	46.40 ± 0.80	m	7.35 ± 0.27	44.17 ± 0.61	m	7.49 ± 0.16	24.41 ± 1.05	st/sm
7	7.18 ± 0.25	24.33 ± 1.29	st/sm	7.22 ± 0.17	21.71 ± 1.08	st	7.24 ± 0.17	27.22 ± 0.70	sm	7.34 ± 0.14	44.30 ± 1.39	m
8	7.18 ± 0.20	45.19 ± 1.08	m	7.20 ± 0.20	46.14 ± 0.86	m	7.11 ± 0.17	29.61 ± 0.83	sm	7.32 ± 0.22	30.40 ± 1.10	sm
9	6.96 ± 0.21	31.14 ± 1.31	sm	7.01 ± 0.14	31.02 ± 0.95	sm	6.95 ± 0.26	27.81 ± 0.62	sm	6.95 ± 0.21	26.79 ± 1.16	sm
10	6.86 ± 0.20	23.82 ± 1.25	st/sm	6.84 ± 0.22	26.92 ± 1.36	sm	6.81 ± 0.18	41.74 ± 0.83	m	6.72 ± 0.22	34.82 ± 1.20	sm
11	6.39 ± 0.22	26.29 ± 1.37	sm	6.68 ± 0.15	25.47 ± 0.98	sm/st	6.56 ± 0.20	30.76 ± 0.69	sm	6.20 ± 0.21	26.63 ± 0.85	sm
12	6.22 ± 0.20	41.58 ± 1.42	m	6.35 ± 0.20	44.12 ± 0.89	m	6.16 ± 0.13	43.38 ± 1.06	m	5.63 ± 0.23	44.86 ± 0.57	m
13	6.10 ± 0.22	29.98 ± 1.15	sm	5.77 ± 0.19	27.09 ± 0.79	sm	5.88 ± 0.20	33.18 ± 1.11	sm	5.61 ± 0.23	26.73 ± 0.48	sm
14	5.40 ± 0.31	33.13 ± 0.95	sm	5.68 ± 0.15	33.02 ± 0.79	sm	5.59 ± 0.18	42.19 ± 1.15	m	4.97 ± 0.16	31.63 ± 0.89	sm

m: metacentric; sm: submetacentric; st: subtelocentric.