Yi chuan xue bao = Acta genetica Sinica最新文献

In the same ethnic group, people residing at different places may have genetic difference. The difference can be the results of migration and admixture events happened in history. To clarify the genetic relationship and micro-evolution of two Bai ethnic populations residing in Yunnan and Hunan province respectively,we investigated their genetic difference from paternal and maternal genealogy with six other ethnic groups as outgroups. Fourteen loci from mtDNA and thirteen loci from Y chromosome were selected for genotyping using PCR-RFLP methods. Result showed that H6 and H8 are the same dominant Y chromosome haplotypes in two Bai groups. However,the distribution of mtDNA haplogroups showed difference between two Bai populations. D, B, M8 are the predominant haplogroups in Hunan Bai ethnic population, whereas M, G, F are dominant in Yunnan Bai ethnic population. Principal Component (PC) analysis based on the Y chromosome haplotypes showed that two Bai ethic populations cluster together. It shows a close paternal genetic relationship between two Bai ethnic populations. From the mtDNA PC plot, it is clear that Hunan Bai is close to Hunan Han and Tujia, whereas Yunnan Bai is close to ethnic groups living in Yunnan province. The difference of mtDNA haplogroup distribution in two Bai people may reflect the maternal gene flow between ethnic groups living in Hunan province after the ancestors of Hunan Bai migrated from Yunnan province to Hunan province 800 years ago.

Abstract: In this paper, Mitomycin C (MMC) was added to different kinds of medium to study the effects of different cultural conditions on the Erwinia herbicola 10025A. For the first time it was confirmed that the expressed activity of the ice-nuclei active protein was different from its transportable manner from the ice nucleation active bacteria (Erwinia herbicola 10025A). The findings indicated that MMC could stimulate the SOS response,and induce the synthesis of some enzymes and proteins, which take part in repairing the damaged DNA. The effects of the MMC on the E. herbicola under different media were different. It could increase the ice nucleation activity of the E. herbicola, forming new small vesicles, which are secreted to the outside of membrane. The importance of this research for study the living mechanism of cells ander poor condition was discussed.

In placental mammals, there is a small group of special genes, which are imprinted so that only one of the parental alleles is actually expressed in target cells. This epigenetic process is named genomic imprinting. Till now, about eighty genes are found to be imprinted in mice and human, and imprinting is conserved in ruminant species as well. This paper emphasized the effects of genomic imprinting on development and animal cloning, exhibited the function of imprint genes by analyzing their origin, and discussed their formation mechanism for understanding the profound effects of this epigenetic modification on development. Many imprinted genes are involved in fetal development, and may influence fetal growth and behavior. Imprinting appears to be particularly important for placental development. Epigenetic deregulation of imprinting may lead to complex diseases in human. And there is now a large body of evidence for loss of appropriate imprinting in numerous tumors. So far, nuclear transfer is a very inefficient process. The rate of cloned animals' surviving was very poor, and there were also frequent inherent anomalies. The most common abnormal phenotypes had the similar characteristics of the consequence due to deregulated expression of imprinted genes,indicating that the key factor to limite cloning efficiency might be the aberrant expression of imprinted genes.

The 400 -600 bp DNA fractions of giant panda containing STR sequences were captured by hybridization with the oligonucleotide probes attached to streptavadin coated magnetic beads (Dynal). The enriched DNA were ligated into pGEM-T and then transformed into E. coil JM109 competent cells. In total 260 positive clones were identified from 2 880 transformants in the libraries which were screened by gamma-32 P radiolabelled probes. Finally, we got 54 sequences and successfully designed 37 pairs of STR primers for giant panda. The results showed that this method is very efficient to isolate microsatellite markers.

Roots were collected from the seedlings inoculated with pathogen Verticillium dahliae after 2, 4, 8, 12, 24, 48, 72 and 96 hours for total RNA extraction. The cDNAs from the inoculated seedlings were used as the tester and those from the control seedlings as the driver. SSH method was employed to find the differently expressed cDNAs responding to the pathogen. T/A clone library was constructed containing 534 clones. The cDNA inserts were amplified from the bacterial clones directly with M13 primers by PCR. The size of the products ranged 0.2 - 1.2 kb with an average size of 0.5 kb. The SSH products were dotted on nylon filters, and the positive clones were screened by virtual Northern blotting with probes of the two kinds of initiative cDNAs. Totally 78 clones which were up-regulated and putatively involved in the defense response of G. barbadense were identified and sequenced. Sequence similarity searches were performed with the Blastn and Blastx. Most of them showed high or partial homology to genes or ESTs induced by different stresses in Arabidopsis thaliana and other species,such as the pathogenesis-related 10 family of G. hirsumtum and disease resistance-responsive family protein in Arabidopsis thaliana. The results would be helpful to understand the molecular mechanisms of disease response in cotton.

A total of 30.1 Mb of publicly available DNA sequence in Aspergillus niculans was researched for mono- to hexanucleotide variable-number tandem repeat (VNTR) to determine its type, size and frequency. A total of 4 837 VNTRs were observed in whole genomic DNA sequence with criteria of VNTR length > 15 bp and 80% matches. Considering all six classes of VNTRs, they occur on average about once every 6.2 kb for mono- to hexanucleotide in genomic DNA. The most abundance variable-number tandem repeat is pentanucleotide repeats; the number was 1 386, followed by hexanucleotide and trinucleotide repeats, the number was 1 228 and 1 199 respectively. The least abundance is dinucleotide repeat, only 144 tracts.

The TAC clone (NK15) containing a ca.50 kb DNA insert was introduced into Agrobacterium tumefaciens strain LBA4404 by electroporation. The NK15 was stable in Agrobacterium tumefaciens strain LBA4404 under kanamycin selection for many generations. The calli of mature embryo of Nongken58S were infected with the Agrobacterium tumefaciens strain LBA4404 carrying NK15. PCR and Southern analyses of transgenic plants indicated that the 50 kb of foreign DNA was transferred into the rice genome, and most of transgenic plants had one copy of the insertion. Genetic and PCR analyses of T1 progeny confirmed that the inserted forgein DNA was stably inherited.

A clonally propagated F2 population (F2CP), derived from the rice cross of Qimiaoxiang/91SP068, was used to map rolled leaf QTLs. As the parent Qimiaoxiang is an unrolling leaf variety, while 91SP068 is a medium rolling variety with about 34% rolling index. One major QTL, rl8, which came from 91SP068, was mapped between two flanking SSR markers, RM6954 and RM6841, on chromosome 5, with genetic distance 3.8 cM, and was 1.0 cM away from RM6954. Its additive effect estimated by composite interval mapping (CIM) was 9.61 in 2002 and 6.23 in 2003, and the dominance effect was also different between two years, -1.19 in 2002 and -4.44 in 2003, respectively. It explained about 20% - 33% of the total phenotypic variation between two years. Furthermore, an integrated physical and genetic map encompassing rl8 region was constructed, and the physical distance of the interval was 542 kb, and the ratio of physical to genetic distance was 144 kb/cM. Based on this research, fine mapping of rolled leaf QTLs will not only facilitate the map-based cloning of the gene itself, but also improve the efficiency of marker-assisted selection in plant breeding.

The mitochondrial DNA (mtDNA) D-loop sequences with 399 bp in 26 individuals from 5 donkey breeds in China were analyzed. Aligned by Clustal W software,the results showed that 23 polymorphic nucleotide sites and only transition with the percentage of 5.76% in 399 bp were observed. In reference to mtDNA D-loop sequences of European domestic donkey as a control, the average percentage of mtDNA D-loop nucleotide variation in 5 Chinese donkey breeds was 1.80%. The average percentages of D-loop nucleotide variation from Liangzhou donkey (LZ), Yunnan donkey (YN), Guanzhong donkey (GZ), Xinjiang donkey (XJ) and Jiami donkey (JM) were 0. 35%, 1.25%, 2.30%, 2.91% and 2.20% respectively. The average sequence divergence estimated from D-loop sequences varied from 0.25% - 5.01% within breeds and 4.51% - 5.51% among breeds, respectively, demonstrating that there existed rather abundant mitochondrial genetic diversity in Chinese donkeys. Comparisons of the 26 sequences revealed 11 mitochondrial haplotypes; the percentage of haplotype was 42.31%. This phenomenon demonstrated that the mitochondrial genetic diversity in Chinese donkey breeds is being reduced. It is urgent to protect the genetic resources of Chinese donkey. The molecular phylogenetic tree of mtDNA D-loop sequences in 5 Chinese donkey breeds,6 sequences of Asian wild ass (Equus asinus kiang, Equus asinus kulan, Equus asinus hemionus;) and 4 sequences of European domestic donkeys from GenBank was constructed by Neighbor-Joining method. It was the first time proved in molecular level that the origin of Chinese donkey breeds was from African wild ass (Equus africanus africanus and Equus africanus somaliensis), not from Asian wild ass as bescribed in the paper.

In this reseanch, 7 microsatellite DNA loci linked with PPAR gene were selected from the published genetic map of chromosome 13 in pig,and polymorphisms of these microsatellites in 100 samples from Sutai pigs (Duroc x Erhualian) populations were detected. Results revealed that the number of alleles were 6-9, heterozygosity 0.59 - 0.81, polymorphism information content 0.51 - 0.76. Effects of S0021, SW1937, SW482, S0222, S0293, S0281 and SWR2054 on meat quality traits were analyzed with PROC GLM of SAS. Results showed that the effects of S0021 on pH value and SW937 on water-holding capacity reached a significant level at P < 0.01 respectively. The effect of S0293 on tenderness and SW482 on BFT were also significant (P < 0.05). S0222, S0281 and SWR2054 had no significant effect on the 7 selected meat qualitytraits (P>0.05).