[The distribution and homology of mitochondrial plasmid-like DNAs in different cucumber varieties].
Four kinds of mitochondrial plasmid-like DNA, designated pC1, pC2, pC3 and pC4, have been found in cucumber (Jinyan No. 4). Their distribution in 14 Cucumber varieties was analyzed. Plasmid-like DNAs were detected in Jinchun No. 2, Jinchun No. 5, Jinxinmici, Jinlu No. 4 and Jinyan No. 4, and the rest 9 varieties contained no plasmid-like DNAs, suggesting that their distribution is irregular. There was homology among the same plasmid-like DNA family in different varieties. pC4 showed homology to the nuclear DNA of Jinyan No. 4, in addition to the nuclear genomes of other 7 varieties either with plasmid-like DNAs or without. The homologous sequences of pC4 in the cucumber nuclear DNA were repetitive. Sequences homologous to pC4 were also found in the nuclear genomes of towel gourd and pumpkin (other cucurbitaceous plant). Therefore, we propose that mitochondrial plasmid-like DNA occurred before cucumber diverged from cucurbit and had integrated into the nuclear DNA. The varieties without plasmid-like DNAs might lost them during evolution.
Li
J Y
JY
Institute for Molecular Biology, Nankai University, Tianjin 300071, China.
Wen
Y D
YD
Fu
J
J
Bai
Y L
YL
Zhang
X M
XM
Gao
C C
CC
D018553:Cucumis sativus / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000737:chemistry; D010957:Plasmids; D017385:Sequence Homology
D004272:DNA, Mitochondrial