Chloroplast DNA sequence of the green alga Oedogonium cardiacum (Chlorophyceae): Unique genome architecture, derived characters shared with the Chaetophorales and novel genes acquired through horizontal transfer

Table 1 General features of Oedogonium and other chlorophycean cpDNAs

Feature	Oedogonium	Stigeoclonium	Scenedesmus	Chlamydomonas
Size (bp)
Total	196,547	223,902	161,452	203,827
IR	35,492	-^a	12,022	22,211
SC1^b	80,363	-^a	72,440	81,307
SC2^c	45,200	-^a	64,968	78,088
A+T (%)	70.5	71.1	73.1	65.5
Sidedness index	0.74	0.95	0.88	0.87
Conserved genes (no.) ^d	99	97	96	94
Introns
Fraction of genome (%)	17.9	7.9	8.6	6.8
Group I (no.)	17	16	7	5
Group II (no.)	4	5	2	2
Intergenic sequences ^e
Fraction of genome (%)	22.6	46.7	34.3	49.2
Average size (bp)	370	1026	517	937
Short repeated sequences
Fraction of genome (%) ^f	1.3	17.8	3.0	15.8

^a Because Stigeoclonium cpDNA lacks an IR, only the total size of this genome is given.
^b SC region with the larger size.
^c SC region with the smaller size.
^d Conserved genes refer to free-standing coding sequences usually present in chloroplast genomes. Genes present in the IR were counted only once.
^e The Oedogonium orf485 and the ORFs encoding the maturase domain of reverse transcriptase in Oedogonium and Scenedesmus (orf1252 and orf932, respectively) were considered as gene sequences.
^f Non-overlapping repeated elements were identified as described in the Methods.

ISSN: 1471-2164