ISSN:
1432-0983
Keywords:
T. aestivum
;
Chloroplast DNA
;
Repeat DNA
;
Evolution
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Low-stringency hybridisation between recombinant plasmids representing the complete T. aestivum chloroplast genome has revealed small repeated DNA segments dispersed through the molecule. Thirty-two repeated DNA segments were detected, and they could be divided into 12 unrelated sets; no repeat was detected as multiple copies. The longest of the small repeats mapped just within the large inverted repeat in spinach and mung-bean ctDNAs. It was found to have been duplicated after the divergence of a cereal progenitor to generate a third, dispensible copy, 0.2 kbp downstream of rbcL. In maize at least, this copy has also become integrated, with rbcL, in the mitochondrial genome. Another of the repeats is thought to have mediated a chloroplast DNA inversion (Howe 1985). Thus the diverse collection of small repeats probably represents some consequences and causes of past recombination events as well as a mechanism for further intramolecular ctDNA recombination. Their possible significance in the restructuring and evolution of chloroplast genomes is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00398291
