Genome size expansion and the relationship between nuclear DNA content and spore size in the Asplenium monanthes fern complex (Aspleniaceae)

Table 4 A summary of the genome size and spore size data obtained for specimens belonging to the Asplenium monanthes clade and related lineages

Species	Mean 2C-value (pg)	Mean CV%	Inferred Ploidy (x)	Holoploid 1C-value (pg)	1C-value SE	Monoploid 1C x-value (pg)	1C x-value SE	Mean spore length
A.formosum	13.61 ± 0.10	2.97	2	6.81	0.09	6.81	0.09	32.07
*A.resiliens* clade
A.resiliens	13.99 ± 0.08	2.87	3	7.00	0.09	4.66	0.06	43.29
A.aff.heterochroum RD9a	18.67 ± 0.08	3.11	4	9.34	-	4.67	-	38.62
A.aff.heterochroum RD75	14.38 ± 0.05	2.39	3	7.19	-	4.79	-	37.43
*A.monanthes* clade
A.hallbergii	26.11 ± 0.11	3.46	3	13.06	0.03	8.70	0.02	45.24
MO1 I	30.17 ± 0.41	4.09	3	15.09	0.15	10.06	0.10	40.11
MO1 II	28.00 ± 0.13	3.06	3	14.00	0.02	9.33	0.01	44.47
MO1 III	26.86 ± 0.21	3.88	3	13.43	0.05	8.95	0.03	43.72
MO2 I	27.06 ± 0.14	4.28	3	13.53	0.16	9.02	0.11	44.51
MO2 II	18.58 ± 0.09	3.00	2	9.29	-	9.29	-	42.11
Spec.nov.1	17.67 ± 0.19	4.26	2	8.84	-	8.84	-	30.87
Spec.nov.2	22.20 ± 0.28	3.54	2	11.10	-	11.10	-	29.71

Mean 2C DNA content (pg) and mean spore length (μm) were only calculated for sub-clades distinguished by low genome size variation (Figure 1). This resulted in separate inferences of genome size and ploidy for the two A.aff.heterochroum specimens (RD75 and RD9a), and A.monanthes subclades: MO1 (I); MO1 (II); MO1 (III); MO2 (I), and MO2 (II) (Figure 1). Published chromosome counts (A.formosum, 2n = 2x = 72; A.monanthes, 2n = 3x = 108; A.resiliens, 2n = 3x = 108) were used to estimate ploidy and hence calculate monoploid genome size (i.e. 2C-value divided by ploidy level). For lineages with unknown ploidy levels, monoploid genome size and ploidy level were estimated according related species. Estimates of ploidy underlined in bold are based on the spore number and spore measurements [29].

ISSN: 1471-2229