Yi chuan xue bao = Acta genetica Sinica最新文献

To discover new genes in a throughput manner,the cap-trapper method published previously was optimized for raising the efficiency in the construction of full-length cDNA library. Using the optimized protocol,we successfully constructed a full-length cDNA library of Aegilops speltoides,which contained 3.0 x 10(6) clones and more than 99% of plaques were recombinant phages. Sequence analysis results indicated that more than 89% of the clones were full-length.

Genetic diversity of domestic quail and two wild quail species distributed in China, wild Japanese quail and wild common quail,was studied by using microsatellite DNA markers. According to the comparison of corresponding genetic index in the three quail populations, such as polymorphism information content (PIC), mean heterozygosity (H) and fixation index etc, wild common quail possessed rich genetic diversity of 4.67 alleles per locus. Its value of PIC and H were the highest, 0.5732 and 0.6621, respectively. Meanwhile, domestic quail had the lowest value, 0.5467 and 0.5933, respectively. Wild Japanese quail had little difference in genetic diversity with domestic quail. In addition,from analyses of fuzzy cluster based on standard genetic distance,the similarity relation matrix coefficients between wild Japanese quail and domestic quail was 0.937, and that between wild common quail and domestic quail was 0.783. All these results showed that wild Japanese quail was closer to the domestic quail in phylogenetic relationship than wild common quail. These results at the molecular level further proved the thesis that domestic quail is originated from wild Japanese quail.

A novel population consisted of 86 single segment substitution lines (SSSLs) were developed from advanced backcrosses between the recipient, Huajingxian 74 and six donors by microsatellite marker-assisted selection (MAS). Fifty-two SSSLs were selected in BC3F2, and 34 others were selected in BC3F3. Every SSSL contains a single chromosome segment introgressed from one donor on the genetic background of Huajingxian 74. The substituted segments in SSSLs were distributed on 12 rice chromosomes. The estimated length of the substituted segments in SSSLs ranged from 1.5 cM to 56.3 cM with an average of 23.0 cM. Total of the substituted segments covered 57.1% of the rice genome.

Progressive muscular dystrophy is a group of inherited disorders characterized by progressive skeletal muscle wasting and weakness, which is not of neurogenic origin. Myostatin, a new member of the TGF-beta super-family, is a negative regulator of skeletal muscle growth. To investigate the possible involvement of myostatin in the development of progressive muscular dystrophy, we cloned and sequenced myostatin cDNAs from the progressive muscular dystrophy patients by RT-PCR. Levels of myostatin mRNA and protein in the patients were analyzed by semi-quantitative RT-PCR and Western blot,respectively. We did not find any mutations in the myostatin cDNA sequences from the progressive muscular dystrophy patients in this study. However, we found that the levels of myostatin transcripts were reduced in some patients and the processing and maturation of myostatin protein were inhibited in some patients. Our data demonstrated that the pathogenesis of some types or subtypes of progressive muscular dystrophy is probably associated with the altered myostatin expression and the processing inhibition of myostatin protein.

PCR-RFLP technique was applied to analyze correlation between the polymorphisms of CSN1 S2 (alpha(s2) casein), CSN3 (kappa casein) and beta-lg (beta-lactoglobulin) genes and milk performance in 69 individuals of Xinong Saanen dairy goat. The results showed that there was significant correlation between different genotypes of CSN1 S2 locus and milk yield:average milk yield of individuals with genotype FF was less than that of genotype NN (P < 0.05); the second lactation milk yield of individuals with genotype NN was over 90 kg higher than that with genotype FF (P < 0.01). This indicates that allele F of CSN1 S2 locus probably has significant negative effect on milk yield. The results of CSN3 gene digested with endonuclease Hind III cleavage showed that no significant difference of milk yield between genotype DE and genotype EE was detected in first, second, third and fourth lactation milk yield and average milk yield (P > 0.05). The results of CSN3 gene with endonuclease Taq I cleavage showed that no significant difference of milk yield among individuals with genotype TT, TC and CC was detected (P > 0.05). No polymorphism was detected in PCR products of CSN3 gene digested with endonuclease Hae III. The analysis of beta-lg gene's 5' flanking region (710 bp) by PCR-RFLP in Xinong Saanen dairy goat showed that milk yield of individuals with genotype AA was higher than that with genotype AB in second, third lactation milk yield and average milk yield (P < 0.05). The results implied that allele A of beta-lg gene's 5' flanking region is probably related to high milk yield.

In this study, the level of amylose was reduced in wheat seeds by RNAi strategy. Because the synthesis of amylose is catalyzed by the granule-bound starch synthase I (GBSSI or WAXY protein), the Waxy gene of wheat was isolated from wheat seeds by using RT-PCR. Southern analysis confirmed that there were three Waxy genes in wheat genome. Northern hybridization showed that Waxy mRNA accumulated in seeds following pollination. By RNAi strategy,the 683 bp sense and antisense fragments in reverse orientation separated by a 150 bp intron were cloned into pCAMBIA 3300 just downstream of the maize ub/1 promoter. By Agrobacteriurn-mediated wheat transformation method, four transgenic plants (Cultivar Yangmai 10) were identified by PCR, RT-PCR and leaf painting assay. The level of amylose in the endosperm were significantly reduced in transgenic seeds as checked by iodine staining and analysis of amylose content. The results indicated that RNA silencing of Waxy gene resulted in low level of amylose in the seeds of transgenic wheat.

Single nucleotide polymorphism (SNP) is the most common type of genetic variant in human genome. Haplotype, defined as a specific set of alleles observed on a single chromosome, or a part of a chromosome,has been an integral part of human genetics for decades. The goal of the international HapMap project is to determine the common patterns of DNA sequence variation and find the Tag SNPs representing all SNPs in the human genome. Some studies demonstrated that the analyses of haplotype defined by the grouping and interaction of several variants rather than any individual SNP correlated with complex phenotypes. Here, we describe the definitions of SNPs, genotype, haplotype and some information of the HapMap project. In this review, we summarize the current three haplotype-inference methods, including Clark' method, EM algorithm and Byes approach, and the different defining methods for haplotype block, as well as the methods for choosing tag SNPs and association studies of complex diseases using haplotype. The major public SNP databases and applications of SNPs and haplotype in common complex diseases and drug response are also introduced in the paper.

Based on hidden Markov models (HMM), the paper utilized reported SCP (Serine Carboxypeptidases) protein sequences as datasets to build HMM profile. To search Arabidopsis thaliana whole proteome,and identified 54 SCPL (Serine Carboxypeptidase-Like) proteins coding genes. The intron-exon structure, the chromosome mapping and the characteristic of coded protein sequences of those 54 putative genes were analyzed in details, revealing seven gene clusters probably resulted from recent gene duplication. This implied that a remarkable number of Arabidopsis thaliana SCPL genes are harboring alternative splice sites. Phylogenetics evolution analysis suggested 88.9% proteins encoded by Arabidopsis genes belong to two string subfamily of carboxypeptidase, I or II, while only 11.1% proteins fall into single string carboxypeptidase III subfamily. Our results indicated besides the facts that all enzymes of this family contained a central catalytic domain of unique topology and three dimensional structure designated as "alpha/beta hydrolase fold", the DNA and their encoded protein sequences also gave clues to phylogentics studies.

One hundred and thirty hybrids derived from the crosses between nine rice strains stabilized in early generation and seven cultivars (Oryza sativa L.). In their F2 populations, 32 uniform strains of different agronomic traits were observed. In the same combination of these uniform strains,there were strains segregating in the Mendelian manner. SSR markers analysis showed that F2 and F3 populations of the uniform strains and their F1 plants displayed the same markers indicating all the uniform strains were homozygous. All the marker bands of parents were simultaneously present on their progeny chromosomes, indicating that the uniform strains must true hybrid origin. The SSR markers of F2 population of segregating strains and their F1 plants showed that the segregating strains were heterzygosity. SSR marker band sites of RM276, RM258, RM248 and RM1 loci in most uniform strains presented at high frequencies bands site different from their parent's. We suggested that during the gamete formation,the genes that linked to ga-1, Rf and ga-8 mutated at certain frequency,and followed by a somatic meiosis of the fecundated zygote. Thus a haploid cell may develop into a homozygous embryo,and the F1 plant was homozygous and the progeny stabilized in early generation.

To survive the freezing marine environment, the Antarctic eel pout, Lycodichthys dearborni synthesizes high concentration of type III antifreeze proteins (AFP III). In the process of characterizing the various types of AFP III mRNA present in the L. dearboni liver, a 2.87 kb mRNA encodes for multiple domains of AFP III was identified. This cDNA encodes 12 tandemly repeated segments, each translates into a 7 kD AFP III molecule plus a 9-amino acid linker. This naturally occurred and functional multimer type III antifreeze protein gene is the first of this kind being identified. The organization strongly mimics the polyprotein structure found in the genes for another type of bio-antifreezes, the antifreeze glycoprotein, AFGP. The AFP III and AFGP are compositionally and structurally completely different, and synthesized by fishes in different suborders. The presence of the similar polyprotein structures in the different types of antifreeze genes may imply a common organizational mechanism in the fish genomes for adapting to the extremely cold polar environment.