The plastid genome of the cryptophyte alga, Guillardia theta:: Complete sequence and conserved synteny groups confirm its common ancestry with red algae
The plastid genome of the cryptophyte alga, Guillardia theta:: Complete sequence and conserved synteny groups confirm its common ancestry with red algae
复制标题
DOI：
10.1007/pl00006462
复制
发表时间：
1999-02-01
影响因子：
3.9
通讯作者：
Penny, SL
中科院分区：
文献类型：
--
作者：
Douglas, SE;Penny, SL
隐芽藻类Guillardia theta的质体基因组(121,524个碱基)已经完成测序。基因组为33%的G+C，包含一个编码两个rRNA顺反子的不完全相同的短重复序列(4.9kb)。大、小单复制区分别为96.3kb和15.3kb。共鉴定出46个光合作用相关基因、5个生物合成功能相关基因、5个复制和分裂相关基因、30个tRNA基因、44个核糖体蛋白基因(26个大亚基和18个小亚基)、3个翻译因子、8个转录机制基因(包括3个假想叶绿体框架)和26个额外的ycf。有8个ORF大于50个氨基酸，其中3个在紫菜、紫菜(Reith和Munholland，1995年)和/或集胞藻基因组(Kaneko等人)的质体基因组上有同源物。1996)，并且可以被指定为新的YCF。基因间隔区非常短，没有检测到内含子，几个基因重叠，所有这些都导致了非常紧凑的基因组。此外，大的基因簇(如核糖体蛋白的基因)被组织成单一的转录单位(Wang等人。1997)，再次产生了经济上有组织的基因组。隐芽叶绿体基因组几乎完全由紫菜上发现的基因簇组成，证实了它与红藻的共同祖先。此外，涉及tRNA基因和rRNA顺反子的重组事件似乎对隐甲体基因组的结构负责，包括反向重复的形成。
The plastid genome of the cryptophyte alga Guillardia theta (121,524 bp) has been completely sequenced. The genome is 33% G+C and contains a short, nonidentical inverted repeat (4.9 kb) encoding the two rRNA cistrons. The large and small single-copy regions are 96.3 and 15.3 kb, respectively. Forty-six genes encoding proteins for photosynthesis, 5 genes for biosynthetic function, 5 genes involved in replication and division, 30 tRNA genes, 44 ribosomal protein genes (26 large subunit and 18 small subunit), 3 translation factors, 8 genes encoding components of the transcriptional machinery including 3 ycfs (hypothetical chloroplast frames), and 26 additional ycfs have been identified. There are eight ORFs larger than 50 amino acids, 3 of which have homologues on the plastid genome of the rhodophyte, Porphyra purpurea (Reith and Munholland 1995) and/or the Synechocystis genome (Kaneko et al. 1996) and can be designated new ycfs. Intergenic spacers are very short, no introns have been detected, and several genes overlap, all resulting in a very compact genome. In addition, large clusters of genes (such as those for the ribosomal proteins) are organized into single transcriptional units (Wang et al. 1997), again resulting in an economically organized genome. The cryptophyte plastid genome is almost completely comprised of clusters of genes that are found on the rhodophyte Porphyra purpurea, confirming its common ancestry with red algae. Furthermore, recombination events involving both tRNA genes and the rRNA cistrons appear to have been responsible for the structure of the cryptophyte plastid genome, including the formation of the inverted repeat.