Liang Li-qun

Mapping QTLs related to head length, eye diameter and eye cross of common carp (Cyprinus carpio L.).

A common carp gynogenetic line including 44 individuals derived from the cross Barbless carp x Hebao-cold tolerance red carp was used to construct a linkage map using 445 markers (265 AFLP markers, 127 SSR markers, 37 EST-SSR markers and 16 RAPD markers). Quantitative traits loci (QTLs) associated with head length, eye diameter, and eye cross were identified by composite interval mapping of the software WinQTLCart2.5. Five QTLs were identified for head length on the linkage group of LG2, LG3, LG40, and LG4, which explained 12.39% to 34.29% of the total variation of the head length. All of their additive effects were negative. Two QTLs were associated with eye diameter on the linkage groups of LG39 (qED-39-1) and LG40 (qED-40-1), which explained 9.77% and 5.62% of the total variation of the eye diameter, respectively. The additive effect of qED-39-1 was positive and that of qED-40-1 was negative. Two QTLs were responsible for eye cross on the linkage group of LG28 and LG20, explaining 8.88% and 8.29% of the total variation of the eye cross, respectively. The additive effect of qEC-28-1 was negative and that of qEC-20-1 was positive.

Screening cold-acclimation differential expression candidate genes in the brain of common carp ( Cyprinus carpio )

In this study, 26 candidate genes were quantified and normalized in the brain cDNA of common carp (Cyprinus carpio) at 23°C and 6°C using double-standard curve method of real-time quantitative PCR. The results showed that five candidates up-regulated in the samples at 6°C (P<0.01) and quantified 2.11, 13.9, 2.52, 7.38, and 1.83 times more than in the samples at 23°C, respectively. Gene function searching indicated that the protein products of these five candidates were elongation of very long chain fatty acids protein, Acyl-CoA desaturase, Transcription initiation factor IIB, Myo-inositol- 1-phosphate synthase, and Blood-brain barrier HT7 antigen individually. Moreover, seven down-regulated candidates were also identified in the same samples at 6°C (P>0.05), and their expression levels were decreased by 21.8%, 25.9%, 16.6%, 23.7%, 15.8%, 16.3%, and 42.5%, respectively, in comparison with the samples at 23°C. These seven down-regulated candidates mainly participated in the inhibition of glycolysis, improvement of cell apoptosis, and intervention of synapse remodeling based on the results of function searching. The five cold-induced genes identified in this study will be used as important elements for fish with cold sensitive through transgenic technology in future.

Screening of microsatellite markers associated with cold tolerance of large yellow croaker (Pseudosciaena crocea R.)

Cold tolerance is one of the major economic characters in fish. In order to discuss the cold tolerance of large yellow croaker (Pseudosciaena crocea R.), fifteen fluorescent dye-labeled microsatellite markers were applied to detect genetic differences between F1 offsprings of cold tolerance group and normal group of large yellow croaker by SSR-PCR. Each group contained 20 randomly and separately sampled individuals. As a result, marker LYC0002 five alleles (LYC0002(104 bp), LYC0002(106 bp), LYC0002(108 bp), LYC0002(110 bp), and LYC0002(112 bp)) were amplified with marker LYC0002 in both groups and 60% (12/20) of individuals had allele LYC0002(112 bp) in cold tolerance group exclusively, which indicated that this allele is probably sensitive to temperature and associated with gene for cold tolerance. In addition, four alleles (LYC0002(106 bp), LYC0002(108 bp), LYC0002(110 bp), and LYC0002(112 bp)) were sequenced individually. Sequence alignments showed that LYC0002(112 bp) allele contains 10 (CA) repeats, the remaining three alleles lacked one (CA) one by one, corresponding to the stepwise mutation model (SMM) of microsatellite.

Correlation and location of EST markers with cold tolerance trait of common carp (Cyprinus carpio L)

Expressed sequence tags (ESTs) are parts of complementary DNAs (cDNAs) with certain gene function.It provides us more information than other neutral markers. The association of EST markers with phenotypes can increase our understanding of the biochemical pathways and mechanisms affecting economically important traits. In this study, 12 candidate EST markers isolated from the cold-induced brain cDNA of common carp (Cyprinus carpio L.) were conducted the correlation analysis of marker and cold tolerance trait of common carp using GLM model of SPSS 17.0 software firstly, then tried to locate them in the genetic linkage map using OneMap software. As a result, eight out of 12 candidate EST makers were separately located in six linkage groups, in which marker CC009(P<0.05) and CC115 (P<0.01) were associated with cold tolerance and mapped to LG38 and LG2, respectively. Homology identity alignments showed that marker CC009 was highly homologous to the known Uridine-cytidine kinase I of Danio rerio with an identity of 94%, and marker CC115 was lowly homologous to the putative glycosyl transferase of Prochlorococcus marinus with an identity of 56%.Expressed sequence tags (ESTs) are parts of complementary DNAs (cDNAs) with certain gene function.It provides us more information than other neutral markers. The association of EST markers with phenotypes can increase our understanding of the biochemical pathways and mechanisms affecting economically important traits. In this study, 12 candidate EST markers isolated from the cold-induced brain cDNA of common carp (Cyprinus carpio L.) were conducted the correlation analysis of marker and cold tolerance trait of common carp using GLM model of SPSS 17.0 software firstly, then tried to locate them in the genetic linkage map using OneMap software. As a result, eight out of 12 candidate EST makers were separately located in six linkage groups, in which marker CC009(P < 0.05) and CC115 (P <0.01) were associated with cold tolerance and mapped to LG38 and LG2, respectivey. Homology identity alignments showed that marker CC009 was highly homologous to the known Uridine-cytidine kinase I of Danio rerio with an identity of 94%, and marker CC115 was lowly homologous to the putative glycosyl transferase of Prochlorococcus marinus with an identity of 56%.