[Analysis of effect of microsatellite markers on Escherichia coli F4 (K88) receptor in different swine breeds].

Four microsatellite markers linked with Escherichia-coli F4 receptor gene were selected from chromosome 13 of pig (authorization) to analyze difference in hereditary between the genotype and F4 receptor adhesive appearance. Results showed that the microsatellite markers were highly polymorphic and the heterozygosities ranged from 0.6117 to 0.7500. The value of PIC was over 0.5749 and the heredity diversity of Chinese pig breeds more higher than oversea's. On F4ab adhesive appearance of S0222, the difference among genotypes was significant in SZL breed. The AC genotype of SW458 had no adhesive appearance in SZL and LW breeds. Marker SW458 can thus be potentially used as a genetic marker for E. coli F4 resistive gene.

[Effect of five genetic Loci related to pig litter size].

To compare the effect of different genes on litter size, we used PCR-RFLP to test the genotypic frequencies of 5 genes related to litter size, i. e. ESR, FSHbeta, PRL, PRLR and NCOA1 and analyzed the effect of various genotypes on total number born (TNB) and number born alive (NBA) within the same populations of Large White (n=158) and Landrace (n=224) pigs. Results showed that the PRLR and NCOA1 loci exerted the greatest impact on litter size: the average TNB from genotype AA was 2.28-3.33 more than that from BB (P<0.01) and the average NBA from AA was 1.57-3.30 more than that from BB (P<0.01). The ESR and FSHbeta loci had a moderate effect on litter size. The average TNB of BB being 0.55-1.18 more than AA (P<0.05) excluding the Landrace, and the average NBA of BB was 0.37-1.20 more than AA (P<0.05). The PRL locus had no significant effect on litter size.

[Screening genes related to 'black' character in wu-ding chicken by delta differential display].

The 'black' character is a cardinal character of black chicken that is very important to the medical value and economical value of black chicken. The study compared gene expression between black chicken and non-black chicken by delta differential display method, and obtained twenty-nine expressed sequence tags(ESTs) by extraction, amplification, purification, northern blotting, cloning and sequencing of gel-embedded DNA. Of twenty-nine ESTs, eight ESTs have high similarity rate with known gene in chicken-beta-trepomyosin gene, cardiac myosin alkali light chain gene, insertionally activated c-Ha-ras oncogene, fra-2 oncogene, 16S rRNA gene and mitochondrion genome sequence, respectively, with similarity rate 97%,100%, 98%, 98%, 98%, 99%, 99% and 97%. Five ESTs have high similarity rate with human TTN gene, human phosphoglucomutase 5 gene, human or mouse signal recongnition particle 54 kD gene, human or mouse ribonuclease/angiogenin inhibitor gene, respectively, with similarity rate 82%, 82%, 87%, 99% and 99%. Their homologous genes in chicken are still not cloned. Thirteen ESTs are novel gene fragments. Of thirteen ESTs, nine ESTs have high similarity with ESTs in database. Four ESTs have not high similarity with any EST in database. The results of gene expression analysis show that one known gene (insertionally activated c-Ha-ras oncogene) fragment and one novel gene fragment are expressed in all non-black chicken and are not expressed in all black chicken, and that one known gene (signal recongnition particle 54 kD gene) fragment is expressed in all black chicken and is not expressed in all non-black chicken. According to these results, we conclude that the expression of insertionally activated c-Ha-ras oncogene, signal recongnition particle 54 kD gene and one novel gene are related to the 'black' character in chicken.

[Progress in the study on diacylgycerol acyltransferase (DGAT)-related genes].

Diacylgycerol Acyltransferase (DGAT) plays an important role in the formation of lipid in different tissues of biological body. DGAT catalyzes the final step in triacylglycerol (TAG) biosynthesis by converting diacylgycerol (DAG) and fatty acyl-coenzyme A (CoA) into triacylglycerol. This enzyme is coded by both DGAT1 and DGAT2. DGAT1 belongs to the gene family of cholesterol acyltransferase (ACAT). DGAT2 belongs to the gene family of monoacylgycerol acyltransferases (MGAT1). This paper reviewed the structure, location on chromosome and biological effect of DGAT-related genes. The relationship between polymorphism and performance of animal was also discussed.

[The genetic variation of two microsatellite markers of Escherichia coli F4(K88) receptor in different swine breeds].

The genetic variation of ETEC F4 receptor in Shaziling and Yorkshire breeds were studied using two micro-satellite markers(S0223 and S0068). The results showed that there were polymorphisms in the two markers, and there were great variations of the gene heterozygosity and Shannon information index in the two breeds. It was also reported that there were differences in K88ab and K88ac receptors in Chinese native breeds and foreign breeds, so the two markers might be the genetic markers of F4 receptor gene.

[Genetic linkage between Atrn gene and microsatellite markers and the effects to some economic traits in pigs].

The genetic polymorphisms of Atrn gene, which were from 174 F0-F5 Danish resource family pigs (DRF) that has undergone five successive generations of inbreeding and 129 F9 Hunan yellow pigs (HY) that were developed by crossbreeding, were tested by PCR-RFLP method, and the effects to carcass and growth traits were also analyzed. The results showed that: (1) Three genotypes of AA, AB, BB were detected by Taq I-RFLP in the two pig breeds, and highly significant differences (P<0.01) in genotype frequencies were found between the two breeds; (2) Based on the linkage analysis of resource family pigs using CRI-MAP V2.4 software, Atrn gene loci in DRF was found to be linked with SW1031 loci on chromosome 17, the recombination frequency and LOD score for Atrn gene were 0.21 and 3.19 respectively; (3) With the least square analysis of multi-variable model, the significant differences among Atrn genotypes were found in ADSG and ABF traits in DRF and also in ADG, ABF and LMP traits in HY (P<0.05 or P<0.01), BB genotype pigs were superior to AA or AB genotype pigs. Based on the above mentioned results, B gene has favorable effects in important economic traits, and thus selection to BB genotype will get favorable effects in important economic traits. This will provide theory basis for Atrn gene being regarded as a candidate gene in pig carcass and growth traits.

Polymorphism of E. coli F18 receptor gene in different pig breeds.

The genetic variation of E. coli F18 receptor(ECF18R) loci in 867 pigs including Large Yorkshire, Landrace, Duroc, Ningxiang pig, Shaziling pig and Daweizi pig was detected by PCR-RFLP with Hin6 I. The results showed as follows: The three exotic breeds including Large Yorkshire, Landrace and Duroc were proved to be polymorphic at the Hin6 I-RFLP site. The average susceptibility genotype frequency of AG and GG in the exotic breeds was 0.94, G allelic frequency was 0.76. The C-->A mutation frequency at M307 site was very low in exotic breeds. The resistance genotype frequency of AA was 0.06. But the three native breeds including Ningxiang pig, Shaziling pig and Daweizi pig presented only GG genotype and no variation at the Hin6 I-RFLP site. The chi 2 value of ECF18R genotype distribution at the Hin6I-RFLP site in different pigs indicated that ECF18R genotype distribution of every exotic pig breed had significant or highly significant differences with three native pig breeds'. The ECF18R genotype distribution of three native pig breeds was the same completely. The others had no difference except that Landrace ECF18R genotype distribution had significant differences with Duroc's in the exotic breeds of pig.

[Progress in Attractin(mahogany/ATRN) gene].

Attractin is an autosomal recessive gene and received great attention within the last few decades. Attractin in different lines has been identified attractin to have multiple roles in regulating physiological process. It affects the balance between agonist and antagonist at receptors on melanocytes, modifies behaviour and basal metabolic rate, intervenes developing the central nervous system and its function, and modulates an interaction between activated T cell and macrophages. The attractin gene encodes a protein that is involved in the suppression of diet-induced obesity, its expression level in the brain has a significant relationship with obesity, the role indicates the therapeutic potential of attractin in the treatment of obesity. Furthermore, the murine attractin locus is located in a region harboring several QTL for body weight and fatness. In this paper, we review the research development of mahogany, introduce the related gene and gene mapping, and summarize its regulating mechanism in the physiological process. Additionally,the further research on the gene is also suggested.

[A search for chromosome 13 QTL in a complex pig family].

A search for chromosome 13 QTL was carried out in a pig family of complex pedigree. The results indicated that a significant QTL on chromosome 13 was segregating in pig family. The QTL significantly affected body weight and average daily gain (P < 0.05), but the effect on backfat thickness was not significant (P > 0.05). Interval mapping localized this QTL between SW1898 and SW398. The estimated linkage position of this QTL was 75.2 cM. The QTL variance estimated at the marker interval was 0.9037 for the body weight and 0.0010 for average daily gain, respectively. This was the region which flanked the PIT1 gene, an essential transcriptional regulatory factor of growth hormone, prolactin and thyrotropin beta subunit. The present result confirmed a previous suggestion of a QTL for early growth traits at the estimated PIT1 position, and further implied that the effect of PIT1 genes on growth and body weight remained for the whole period of individual growth and development. Aditional evidence was also found which suggested a backfat QTL on chromosome 13, at a location approximately 28.3-63.4 cM apart from the one for body weight and growth, but the level of significance was not consistent in different generations.

[Experimental results on enterotoxigenic E.coli F18 receptor genotypes].

A total of 158 pigs of Yorkshire, Landrace and Duroc were selected from some swine breeding farms in Hunan province. The genotypes of enterotoxigenic E.coli F18 receptor were tested by PCR-RFLP. The results showed that the frequency of resistant genotype AA was 0.11,the frequencies of susceptibility genotype AG and GG were 0.35 and 0.54 respectively.