Unusual structure of geranium chloroplast DNA: A triple-sized inverted repeat, extensive gene duplications, multiple inversions, and two repeat families
AUTOR(ES)
Palmer, Jeffrey D.
RESUMO
Physical and gene mapping studies reveal that chloroplast DNA from geranium (Pelargonium hortorum) has sustained a number of extensive duplications and inversions, resulting in a genome arrangement radically unlike that of other plants. At 217 kilobases in size, the circular chromosome is about 50% larger than the typical land plant chloroplast genome and is by far the largest described to date, to our knowledge. Most of this extra size can be accounted for by a 76-kilobase inverted duplication, three times larger than the normal chloroplast DNA inverted repeat. This tripling has occurred primarily by spreading of the inverted repeat into regions that are single copy in all other chloroplast genomes. Consequently, 10 protein genes that are present only once in all other land plants are duplicated in geranium. At least six inversions, occurring in both the inverted repeat and large single-copy region, must be postulated to account for all of the gene order differences that distinguish the geranium genome from other chloroplast genomes. We report the existence in geranium of two families of short dispersed repeats and hypothesize that recombination between repeats may be the major cause of inversions in geranium chloroplast DNA.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=304297Documentos Relacionados
- Spinacia oleracea chloroplast DNA sequence homology with ARS and ARC elements within the inverted repeat, upstream of the rDNA operon.
- Chloroplast genomes of two conifers lack a large inverted repeat and are extensively rearranged.
- Sequence of the trnH gene and the inverted repeat structure deletion site of the broad bean chloroplast genome.
- Transcription of two classes of rat growth hormone gene-associated repetitive DNA: differences in activity and effects of tandem repeat structure.
- Dynamics of cruciform extrusion in supercoiled DNA: use of a synthetic inverted repeat to study conformational populations.