Characterization of a novel Tc1-like transposon from bream (Cyprinidae, Megalobrama) and its genetic variation in the polyploidy progeny of bream-red crucian carp crosses.
Crossing the cyprinids diploid blunt snout bream Megalobrama amblycephala (BSB) and Carassius auratus red var. (RCC) generated sterile triploid (3nRB) and fertile tetraploid (4nRB) hybrid offspring. Utilizing inverted terminal repeats (ITRs) of transposon Tdr1 from Danio rerio as PCR primer, the results showed that evident change in the number of Tc1-like transposons in 4nRB relative to BSB occurred, whereas such change did not arise in 3nRB compared to BSB. No Tc1-like transposon was found in RCC. A novel transposon was isolated from both BSB and 3nRB and designated as Tma1, which consisted of multiple copies after dot-blot hybridization. Based on the analysis of PCR amplified flanking sequence, characterization of Tma1 indicated that this element flanked by a duplicated TA dinucleotide and harbored an ITR of about 224 bp. Tma1 also harbored an incomplete transposase gene. Another novel transposon designated as Tte1 was detected in 4nRB, which harbored an ITR of roughly 130 bp and consisted of multiple copies, but had no transposase gene. The analysis of PCR amplification and Southern blot hybridization showed that DNAs of 4nRB, which were hybridized to DIG-labeled pTma1, did not give band by PCR with Tma1 primer, on the other hand, 7 of 15 DNA samples from BSB, which were hybridized to DIG-labeled pTte1, did not produce band by PCR with Tte1 primer. These results suggest that Tte1 may be a recent invasion in BSB population and burst in 4nRB offspring. Our data provide clues as to the possible role of transposons as a driving mechanism for genomic evolution.
Liu
Dong
D
Key Laboratory of Protein Chemistry and Fish Developmental Biology of the Education Ministry of China, College of Life Sciences, Hunan University, Changsha, 410081, People's Republic of China. liudong66@163.com
You
Cuiping
C
Liu
Shaojun
S
Liu
Liangguo
L
Duan
Wei
W
Chen
Song
S
Yan
Jinpeng
J
Liu
Yun
Y
D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D003433:Crosses, Genetic; D003530:Cyprinidae / Q000235:genetics*; D004251:DNA Transposable Elements / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D016678:Genome / Q000235:genetics; D006054:Goldfish / Q000235:genetics*; D006238:Haploidy; D006824:Hybridization, Genetic; D008297:Male; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011123:Polyploidy; D020079:Terminal Repeat Sequences / Q000235:genetics
D004251:DNA Transposable Elements