페이지 정보작성자 관리자 댓글 0건 조회 943회 작성일 16-11-02 11:11
Background: The red algae (Rhodophyta) and green algae plus plants (Viridiplantae) diverged over one billion years ago within the kingdom Archaeplastida. These photosynthetic lineages provide an ideal model to study plastid genome reduction in deep time. To this end, we assembled a large dataset of plastid genomes yet available, including 48 from the red algae (17 complete and 3 partial genomes produced for this analysis) to elucidate the evolutionary history of these organelles.
Results: We find extreme conservation of plastid genome architecture in the major lineages of the multicellular Florideophyceae red algae. Only three minor structural types were detected in this group that are explained by recombination events of the duplicated rDNA operons. A similar high level of structural conservation (however, with different gene content) was found in seed plants. Three major plastid genome architectures were identified in representatives of 46 orders of angiosperms and 3 orders of gymnosperms.
Conclusion: Our results provide a comprehensive accounting of plastid gene loss and rearrangement events of genome architecture within Archaeplastida and lead to one over-arching conclusion. From an ancestral pool of highly rearranged plastid genomes in red and green algae, the aquatic (Florideophyceae) and terrestrial (seed plants) multicellular lineages display high conservation in plastid genome architecture. This phenomenon correlates with, and may be explained by the independent and widely divergent (separated by >400 million years) origins of complex sexual cycles and reproductive structures that led to the rapid diversification of these lineages.
등록된 댓글이 없습니다.