SUSCEPTIBILITY LOCI FOR UMBILICAL HERNIA IN SWINE DETECTED BY GENOME-WIDE ASSOCIATION.

Umbilical hernia (UH) is a complex disorder caused by both genetic and environmental factors. UH brings animal welfare problems and severe economic loss to the pig industry. Until now, the genetic basis of UH is poorly understood. The high-density 60K porcine SNP array enables the rapid application of genome-wide association study (GWAS) to identify genetic loci for phenotypic traits at genome wide scale in pigs. The objective of this research was to identify susceptibility loci for swine umbilical hernia using the GWAS approach. We genotyped 478 piglets from 142 families representing three Western commercial breeds with the Illumina PorcineSNP60 BeadChip. Then significant SNPs were detected by GWAS using ROADTRIPS (Robust Association-Detection Test for Related Individuals with Population Substructure) software base on a Bonferroni corrected threshold (P = 1.67E-06) or suggestive threshold (P = 3.34E-05) and false discovery rate (FDR = 0.05). After quality control, 29,924 qualified SNPs and 472 piglets were used for GWAS. Two suggestive loci predisposing to pig UH were identified at 44.25MB on SSC2 (rs81358018, P = 3.34E-06, FDR = 0.049933) and at 45.90MB on SSC17 (rs81479278, P = 3.30E-06, FDR = 0.049933) in Duroc population, respectively. And no SNP was detected to be associated with pig UH at significant level in neither Landrace nor Large White population. Furthermore, we carried out a meta-analysis in the combined pure-breed population containing all the 472 piglets. rs81479278 (P = 1.16E-06, FDR = 0.022475) was identified to associate with pig UH at genome-wide significant level. SRC was characterized as plausible candidate gene for susceptibility to pig UH according to its genomic position and biological functions. To our knowledge, this study gives the first description of GWAS identifying susceptibility loci for umbilical hernia in pigs. Our findings provide deeper insights to the genetic architecture of umbilical hernia in pigs.

A genomewide association study of feed efficiency and feeding behaviors at two fattening stages in a White Duroc × Erhualian F population.

Feeding efficiency is a multifactorial and economically important trait in pigs. Genetic improvement of feeding efficiency will greatly benefit the pig industry. In the past decades, the hog market weight has increased worldwide. However, whether the genetic architecture of feeding efficiency is same or not at early and late fattening periods is unclear. To map genomic regions for feed efficiency and feeding behavior traits at early (n ≥ 384) and late (n ≥ 334) growth stages in pigs, we performed genomewide association studies for feed to gain ratio (FCR), residual feed intake (RFI), daily feed intake, daily visit times, daily feeding time (DFT), feed intake per second (FIPS), and feed intake per visit during 3 periods (2 stages and overall) in a White Duroc × Erhualian F2 intercross population. Six chromosomal regions showed significant association with these traits, of which 4 loci were reported for the first time. Our results confirmed the QTL of FCR around 34 Mb on SSC7 and RFI around 134 Mb on SSC12. Of note, 2 regions were associated with more than 1 trait. One was around 36 Mb on SSC7, and there were 47 and 67 SNP associated with FCR from 120 to 210 and from 120 to 240 d, respectively. The top SNP is located in a 2.88-Mb linkage disequilibrium (LD) block that harbors 44 genes. We propose the high mobility group AT-hook 1 gene as a plausible candidate gene in this region. The other was evidenced around 53 Mb on SSC12, which had multiple association signals for DFT and FIPS. The top SNP is located in a 211-kb LD block that harbors only 1 annotated gene, WSCD1, which encodes a protein with sulfotransferase activity and involves the glucose metabolism and, therefore, appears to be a plausible candidate gene. Except the region on SSC12 associated with DFT at both stages, the rest of the regions associated with the traits at only 1 stage, so the genetic architectures of the 2 stages are not same.

[Characterization of morphologic, cytochemical and immunological features in myeloperoxidase negative acute myeloid leukaemia].

Ten cases of acute myeloperoxidase-negative myeloid leukaemia (AML) were reported. They had no typical mopholocid negative for lymphocic features and were negative antigens. However 5 cases were positive for NSE/NaF stain. 9 of the 10 cases expressed more than one myeloid antigens. The authors are of the opinion that it is very difficult to diagnose myeloperoxidase-negative AML and combination of cytochemical and immunological techniques is recommended in this respect.

[Some difficult problems in the classification of acute leukemia].

The authors presented 5 cases of ANLL and 6 cases of ALL according to FAB classification and further classified them with leukemic cell morphology, cytochemistry and immunophenotyping. Five cases of them belonged to low grade peroxidase ANLL (LP-ANLL), 4 to hybrid acute leukemia (HAL) and 2 to acute undifferentiated leukemia (AUL). The importance of immunophenotyping of leukemic cells in classification of acute leukemia was emphasized and the criteria for diagnosis of LP-ANLL, HAL and AUL discussed. The authors are of the opinion that the diagnosis of these three kinds of acute leukemia is difficult and the prognosis is serious.

A joint genomewide association analysis of pig leg weakness and its related traits in an F2 population and a Sutai population.

To map genomic loci for leg weakness-related traits in pigs, leg scores and gait scores were recorded at 219 ± 18 d in a White Duroc × Erhualian F2 intercross population and a Chinese Sutai population. The biceps brachii muscle was dissected from the right front leg and its length and weight were measured after slaughter at 240 ± 3 d in the 2 populations. The 2 populations were genotyped using the Porcine SNP60 BeadChip, and genomewide association studies were performed on them separately and jointly. A total of 12 significant loci were detected in the 3 populations, including 6 at the 1% genomewide significant level on SSC7 and SSCX and 2 at the 5% genomewide significant level on SSC7 and SSCX. All of them confirmed the previous QTL findings except 1 locus for gait score of front legs on SSC5, which was reported for the first time. The most prominent locus was identified in a 2.15 Mb linkage disequilibrium block on SSC7 for both leg weakness and the growth of the biceps brachii muscle, which is worth further investigation. The significant SNP identified in the Sutai population could directly be explored in marker-assisted selection to improve leg soundness of the Sutai pig. As expected, it is generally more powerful to identify significant regions in the combined population compared with a single population. To our knowledge, this was the first genomewide association study for weight and length of the biceps brachii muscle in pigs.

The radiation protection and therapy effects of mesenchymal stem cells in mice with acute radiation injury.

The aim of this study was to investigate the effects and mechanisms of mesenchymal stem cells (MSCs) on haematopoietic reconstitution in reducing bone marrow cell apoptosis effects in irradiated mice, and to research the safe and effective dosage of MSCs in mice with total body irradiation (TBI). After BALB/c mice were irradiated with 5.5 Gy cobalt-60 gamma-rays, the following were observed: peripheral blood cell count, apoptosis rate, cell cycle, colony-forming unit-granulocyte macrophage (CFU-GM) and colony-forming unit-fibroblast (CFU-F) counts of bone marrow cells and pathological changes in the medulla. The survival of mice infused with three doses of MSCs after 8.0 Gy or 10 Gy TBI was examined. The blood cells recovered rapidly in the MSC groups. The apoptotic ratio of bone marrow cells in the control group was higher at 24 h after radiation. A lower ratio of G0/G1 cell cycle phases and a higher ratio of G2/M and S phases, as well as a greater number of haematopoietic islands and megalokaryocytes in the bone marrow, were observed in the MSC-treated groups. MSCs induced recovery of CFU-GM and CFU-GM and improved the survival of mice after 8 Gy TBI, but 1.5 x 10(8) kg(-1) of MSCs increased mortality. These results indicate that MSCs protected and treated irradiated mice by inducing haematopoiesis and reducing apoptosis. MSCs may be a succedaneous or intensive method of haematopoietic stem cell transplantation under certain radiation dosages, and could provide a valuable strategy for acute radiation syndrome.

Biological dose estimation for two severely exposed patients in a radiation accident in Shandong Jining, China, in 2004.

PURPOSE: To estimate the biological doses for two severely exposed subjects (A and B) in a radiation accident in Shandong Jining, China in 2004. MATERIALS AND METHODS: Conventional chromosome aberration analysis and cytokinesis-block micronuclei (CBMN) assay were performed in peripheral blood and bone marrow samples on two subjects after the accident. A new dose-effect curve and the nuclear division index (NDI) obtained from in vitro irradiation experiments using high dose of (60)Co gamma-rays were used to estimate the exposed doses. RESULTS: No metaphases or binucleated cells were observed in the peripheral blood cultures from either of the subjects. However, metaphases and binucleated cells were obtained from both subjects after bone marrow cultures. Both dicentric/ring and micronuclei yields were very high. The dose estimated for A and B were 20.0 Gy and 8.8 Gy, respectively, by dicentric/ring scoring, similar to the data by combination of the CBMN and NDI (CBMN + NDI) assay. The estimated doses by the two methods were in accordance with the clinical symptoms. CONCLUSION: The new curve, together with the CBMN + NDI assay, are reliable for estimating higher doses of irradiation. In future radiation accidents, the accuracy and significance of these methods can be further tested.

A whole genome scan for quantitative trait loci for leg weakness and its related traits in a large F2 intercross population between White Duroc and Erhualian.

To detect QTL for leg weakness and its related traits in pigs, a total of 1,484 F(2) pigs were recorded for leg (at 76 and 213 d) and gait scores (at 153 and 223 d) in a White Duroc x Erhualian intercross. The length and weight of the biceps brachii muscle were measured after slaughter at 240 d. A genome scan was performed with 183 microsatellite markers in the population. A total of 42 QTL were detected, including 16 at the 1% genome-wide significant level and 6 at the 5% genome-wide significant level. Thirty-eight of the 42 QTL showed significant additive effects, and 14 had significant dominance effects. At least 2 QTL were detected for each trait except for leg score at 76 d, for which no QTL was identified. Some of the QTL for leg and gait scores confirmed previous findings. Eighteen QTL were detected for weight and length of the biceps brachii muscle. To our knowledge, this was the first report about QTL for weight and length of the biceps brachii muscle in pigs. Two chromosome regions each on SSC4 and SSC7 showed significant and multiple associations with both leg weakness and growth of the biceps brachii muscle, which are worthwhile for further investigation.