[Clinical characteristics of aplastic anemia patients with abnormal autoantibodies and the impact of autoantibodies on immunosuppressive therapy response].

Objective: To investigate the clinical characteristics of patients with acquired aplastic anemia (AA) accompanied by abnormal antinuclear antibody (ANA) and autoantibodies and their effects on the efficacy of immunosuppressive therapy (IST). Method: A retrospective case-control study was conducted, analyzing the clinical data of 291 patients with AA who underwent IST and were screened for autoantibodies at initial diagnosis between January 2018 and December 2019 at Blood Diseases Hospital, Chinese Academy of Medical Sciences. According to the titer of ANA at the initial diagnosis, extracted nuclear antigen antibodies (ENAs) abnormality and the change of ANA titer after treatment, the treatment responses of 3 months and 6 months after IST were compared. The correlation between clinical features and ANA abnormality was analyzed by univariate and multivariate logistic regression analysis. The parameters of univariate analysis P<0.1 were included in multivariate analysis, stepwise regression analysis and subgroup analysis. Results: A total of 291 patients were included in the study, of which 145 (49.83%) were male. Among all patients, 147 (50.52%) tested positive for ANA at initial diagnosis, with titers of 1∶100, 1∶320, and 1∶1 000 observed in 94, 47, and 6 cases, respectively. Female gender, older age, presence of paroxysmal nocturnal hemoglobinuria (PNH) clone, and higher levels of IgG, IgA, and thyroid hormone were significantly associated with ANA positivity at initial diagnosis, while white cell counts, reticulocytes, and free triiodothyronine were significantly lower than that of ANA-negatively patients (all P<0.05). Furthermore, logistic regression analyses revealed that female gender (OR=1.980, 95%CI 1.206-3.277), older age (OR=1.017, 95%CI 1.003-1.032), and presence of PNH clone (OR=1.875, 95%CI 1.049-3.408) were independent risk factors for ANA positivity at initial diagnosis. Subgroup analysis indicated that the risk of ANA positivity at initial diagnosis was even higher in PNH clone-positive patients in the subgroups of females (OR=1.24, 95%CI 1.02-1.51), severe AA (OR=1.26, 95%CI 1.07-1.47), and age≥40 years (OR=1.26, 95%CI 1.05-1.52) (all P<0.05). However, ANA titers at initial diagnosis, presence of other abnormal ENAs, and changes in ANA titers after treatment with IST were not correlated with treatment response (all P>0.05). Conclusions: Approximately 50% of patients with AA had abnormal ANA, and their presence was significantly associated with female gender, older age, and presence of PNH clone at initial diagnosis. However, the presence of abnormal ANA and changes in ANA titers after treatment did not affect the efficacy of IST in patients with AA.

[The clinical and laboratory characteristics of congenital pyruvate kinase deficiency].

Clinical data of 19 patients with congenital pyruvate kinase deficiency were analyzed. Insufficient pyruvate kinase confirmed the diagnosis. Laboratory parameters of hemolysis were summarized. In cases of neonatal hyperbilirubinemia and unexplained hemolytic anemia, pyruvate kinase activity and next generation sequencing test may help the early diagnosis.

Molecular characterization, expression patterns, and promoter activity analysis of PGM1 in pigs.

The phosphoglucomutase 1 (PGM1) gene was differentially expressed in tissues of Chinese Meishan and Large White pigs. In this study, the promoter region, expression profile, and genetic mutations of the gene were determined. Expression of a 5'-deletion in both C2C12 and PK-15 cells showed that a negative regulatory element was at -1871 to +185 bp and a positive regulatory element was at -1158 to +185 bp. Among the different types of muscle fibers, PGM1 had the highest expression in both longissimus dorsi and biceps femoris. The expression was concentrated in the muscle fibers at different growth stages of Meishan and Large White pigs. The synonymous mutation C462T in the coding sequence was confirmed by polymerase chain reaction-restriction fragment length polymorphism, and the frequency of the C allele was dominant in Chinese indigenous breeds. Association analysis with lean meat showed that the C462T site was different.

Transcriptional analysis of the porcine TTID gene and association of different TTID genotypes with carcass traits.

The titin immunoglobulin domain (TTID) protein localizes to the Z line in muscle and binds to alpha-actinin and gamma-filamin. It plays an indispensable role in stabilizing and anchoring of thin filaments. In this study, the 5'-regulatory region of the porcine TTID gene was analyzed with bioinformatic methods. Another objective of this study was to further investigate the polymorphism in the intron 6 of the porcine TTID gene. We determined allele frequency among six Chinese porcine purebreds. The polymorphisms were genotyped in a population of 280 F2 pigs representing two Large White x Meishan reference families. Different TTID genotypes were significantly associated with carcass traits, including skin percentage (P < 0.05), loin eye area (P < 0.05), and average skin thickness (P < 0.01). Our study will continue to lay the groundwork for further investigations into the detailed function of the porcine TTID gene.

Expression patterns and promoter activity analysis of UGP2 in pigs.

The function of the UDP-glucose pyrophosphorylase 2 gene (UGP2) in pig is not clear. In the present study, we used RNA isolated from Large White pigs and Chinese indigenous MeiShan pigs to examine the temporal coordination of changes in gene expression within muscle tissues. We cloned both the complete genomic DNA sequence and 2077-bp 5ꞌ-flanking sequence of porcine UGP2, to determine the genomic sequence. Real-time RT-PCR revealed that UGP2 was highly expressed in liver and skeletal muscle of MeiShan pigs. Among different types of muscle fibers, the UGP2 had the highest expression in both soleus muscle and longissimus dorsi in Large White pigs. In the progression of muscle fibers at different growth stages, UGP2 plays a role in the early days after birth in Large White pigs, while in MeiShan pigs it is important later. Furthermore, the 5ꞌ-flanking sequence we cloned exhibited the promoter activity of UGP2, and the sequence 588 bp upstream from the transcriptional site had the greatest activity.

Differential expression and effect of the porcine ANGPTL4 gene on intramuscular fat.

In a previous study, we investigated differences in gene expression in backfat between Meishan and Large White pigs and their F1 hybrids, Large White x Meishan, and Meishan x Large White pigs. One potential differentially expressed sequence tag from the mRNA differential display was a homolog of the human angiopoietin-like 4 (ANGPTL4) gene, which encodes a protein that is secreted by both liver and white adipose tissues and can inhibit lipoprotein lipase activity and stimulate white adipose tissue lipolysis. Here, ANGPTL4 mRNA was found to be upregulated in the backfat of Large White compared with that in the Meishan pigs and the F1 hybrids, Meishan x Large White and Large White x Meishan, whereas expression was lowest both in the longissimus dorsi and the heart, as shown by the tissue distribution profile. Only one mutation, a G/A transition located in the third intron, was found. The ANGPTL4 G/A polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) showed a significant effect on intramuscular fat (IMF), water moisture of the longissimus dorsi, meat marbling of the longissimus dorsi, and pH of the longissimus dorsi (P < 0.05). This site seemed to be significantly (P < 0.05) additive in its actions on IMF, water moisture, and pH, whereas it showed significant dominance in its action on meat marbling (P < 0.05). This locus can be potentially considered as a marker for IMF improvement.

Development of a DNA microarray-based multiplex assay of avian influenza virus subtypes H5, H7, H9, N1, and N2.

Outbreaks of highly pathogenic avian influenza have caused considerable economic losses in the poultry industry and have also resulted in human deaths since 2004. Rapid subtyping of highly pathogenic avian influenza viruses(HPAIVs) in clinical specimens is a prerequisite of prompt control of disease and prevention of its spreading. In this study, we describe development of a DNA microarray-based detection and subtyping of HPAIVs in field samples. DNA copies of matrix (M) protein genes for the H5, H7, and H9 subtypes of hemagglutinin (HA) and the N1 and N2 subtypes of neuraminidase (NA) were prepared by RT-PCR and specific primers and then spotted onto aldehyde slides to form DNA microarrays. The HPAIV samples to be tested were subjected to total RNA isolation, RT-PCR with universal primers and Cy3 labeling, and the obtained double-stranded DNAs (targets) were finally hybridized with DNA microarrays (probes). A fluorescent spot on the microarray, detected by scanning indicated positive hybridization, i.e. the involved subtype. The assay was specific as various heterologous viruses or HPAIVs of other subtypes tested were negative. No cross-hybridization among different subtypes could be detected. The assay was more sensitive than RT-PCR and chicken embryo inoculation and could be also used for field samples. Summing up, the assay has proved useful for simultaneous detection and differentiation of main epidemic HPAIV subtypes.

[Clinical and gene mutation characteristics of patients with hereditary ellipsocytosis: nine cases report and literature review].

Objective: To report gene mutations in nine patients with hereditary elliptocytosis (HE) and analyze the characteristics of pathogenic gene mutations in HE. Methods: The clinical and gene mutations of nine patients clinically diagnosed with HE at Institute of Hematology & Blood Diseases Hospital from June 2018 to February 2022 were reported and verified by next-generation sequencing to analyze the relationship between gene mutations and clinical phenotypes. Results: Erythrocyte membrane protein gene mutations were detected among nine patients with HE, including six with SPTA1 mutation, one with SPTB mutation, one with EPB41 mutation, and one with chromosome 20 copy deletion. A total of 11 gene mutation sites were involved, including 6 known mutations and 5 novel mutations. The five novel mutations included SPTA1: c.1247A>C (p. K416T) in exon 9, c.1891delG (p. A631fs*17) in exon 15, E6-E12 Del; SPTB: c.154C>T (p. R52W) ; and EPB41: c.1636A>G (p. I546V) . Three of the six patients with the SPTA1 mutation were SPTA1 exon 9 mutation. Conclusion: SPTA1 is the most common mutant gene in patients with HE.

[The effect of on-demand glucocorticoid strategy on the occurrence and outcome of p-ALG-associated serum sickness in aplastic anemia].

Objective: To investigate the effect of on-demand glucocorticoid strategy on the occurrence and outcome of porcine anti-lymphocyte globulin (p-ALG) -associated serum sickness in aplastic anemia (AA) . Methods: The data of AA patients who received in the Anemia Diagnosis and Treatment Center of Haematology Hospital, CAMS & PUMC from January 2019 to January 2022 were collected. Among them, 35 patients were enrolled in the on-demand group, with the glucocorticoid strategy adjusted based on the occurrence and severity of serum sickness; 105 patients were recruited in the usual group by matching the age and disease diagnosis according to 1∶3 ratio in patients who received a conventional glucocorticoid strategy in the same period. The incidences, clinical manifestations, treatment outcomes of serum sickness, and glucocorticoid dosage between the two groups were analyzed. Results: The incidences of serum sickness in the on-demand group and the usual group were 65.7% and 54.3% (P=0.237) , respectively. The median onset of serum sickness was the same [12 (9, 13) d vs the 12 (10, 13) d, P=0.552], and clinical symptoms and signs, primarily joint, and/or muscle pain, fever, and rash were similar. Severity grades were both dominated by Grades 1-2 (62.8% vs 51.4%) , with only a few Grade 3 (2.9% vs 2.9%) , and no Grades 4-5. No significant difference in the serum sickness distribution (P=0.530) . The median duration of serum sickness was the same [5 (3, 7) d vs 5 (3, 6) d, P=0.529], and all patients were completely cured after glucocorticoid therapy. In patients without serum sickness, the average dosage of prophylactic glucocorticoid per patient in the usual group was (469.48 ±193.57) mg (0 in the on-demand group) . When compared to the usual group, the average therapeutic glucocorticoid dosage per patient in the on-demand group was significantly lower [ (125.91±77.70) mg vs (653.90±285.56) mg, P<0.001]. Conclusions: In comparison to the usual glucocorticoid strategy, the on-demand treatment strategy could significantly reduce glucocorticoid dosage without increasing the incidence of serum sickness; in addition, the duration of serum sickness and the incidence of above Grade 2-serum sickness were similar.

[Metagenomic next-generation sequencing of plasma for the identification of bloodstream infectious pathogens in severe aplastic anemia].

Objective: To analyze the diagnostic value of cell-free plasma metagenomic next-generation sequencing (mNGS) pathogen identification for severe aplastic anemia (SAA) bloodstream infection. Methods: From February 2021 to February 2022, mNGS and conventional detection methods (blood culture, etc.) were used to detect 33 samples from 29 consecutive AA patients admitted to the Anemia Diagnosis and Treatment Center of the Hematology Hospital of the Chinese Academy of Medical Sciences to assess the diagnostic consistency of mNGS and conventional detection, as well as the impact on clinical treatment benefits and clinical accuracy. Results: ①Among the 33 samples evaluated by mNGS and conventional detection methods, 25 cases (75.76%) carried potential pathogenic microorganisms. A total of 72 pathogenic microorganisms were identified from all cases, of which 65 (90.28%) were detected only by mNGS. ②All 33 cases were evaluated for diagnostic consistency, of which 2 cases (6.06%) were Composite, 18 cases (54.55%) were mNGS only, 2 cases (6.06%) were Conventional method only, 1 case (3.03%) was both common compliances (mNGS/Conventional testing) , and 10 cases (30.3%) were completely non-conforming (None) . ③All 33 cases were evaluated for clinical treatment benefit. Among them, 8 cases (24.24%) received Initiation of targeted treatment, 1 case (3.03%) received Treatment de-escalation, 13 cases (39.39%) received Confirmation, and the remaining 11 cases (33.33%) received No clinical benefit. ④ The sensitivity of 80.77%, specificity of 70.00%, positive predictive value of 63.64%, negative predictive value of 84.85%, positive likelihood ratio of 2.692, and negative likelihood ratio of 0.275 distinguished mNGS from conventional detection methods (21/12 vs 5/28, P<0.001) . Conclusion: mNGS can not only contribute to accurately diagnosing bloodstream infection in patients with aplastic anemia, but can also help to guide accurate anti-infection treatment, and the clinical accuracy is high.

[Hematologic responses to avatrombopag switch in TPO-RA refractory aplastic anemia].

Objective: Short-term efficacy and safety of afatrombopag conversion therapy in patients with aplastic anemia (AA) who were previously ineffectively treated with intense immunosuppressive therapy (IST) combined with TPO receptor Agonist (TPO-RA) or who were unable to tolerate the side effects of TPO-RA. Methods: Analysis of patients with severe aplastic anemia (SAA) treated in Institute of Hematology & Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College from January 2021 to December 2021 who received IST combined with TPO-RA (eltrombopag/hatrombopag) for at least 6 months, but was ineffective for at least 3 months or patients who cannot continue to use TPO-RA due to side effects, and switched from TPO-RA to avatrombopag (APAG) , and treated for at least 6 months. This study analyzed its short-term efficacy and evaluated its safety. Results: The median age was 54 (14-68) years old among the 16 patients with AA (8 male and eight female) . A total of ten patients (refractory group) who did not respond to IST combined with TPO-RA were converted to APAG median therapy for 6 (6-10) months. Only seven patients (70% ) obtained trilineage HR [four cases of complete treatment response (CTR) , one case of good treatment response (GPR) , and two cases of partial treatment response (PR) ], all of which began to take effect at 3 months of APAG treatment. There were six patients with TPO-RA intolerance, and APAG was treated for 6 (2 to 8) months. About four patients (67% ) received HR (three GPR cases and one PR case) , of which two patients received PR at 3 months and four patients received HR at 6 months of APAG treatment. No APAG-related grade 2 or more adverse events occurred during the APAG therapy, no thrombotic events occurred, no fibrologic tissue hyperplasia was found in the bone marrow pathology reexamination at 6 months of treatment, and none of the patients discontinued the drug due to adverse events. Conclusion: APAG may be a better switching treatment option for patients with AA who are refractory or are intolerant to TPO-RA.

[Reassessing the six months prognosis of patients with severe or very severe aplastic anemia without hematological responses at three months after immunosuppressive therapy].

Objective: To reassess the predictors for response at 6 months in patients with severe or very severe aplastic anemia (SAA/VSAA) who failed to respond to immunosuppressive therapy (IST) at 3 months. Methods: We retrospectively analyzed the clinical data of 173 patients with SAA/VSAA from 2017 to 2018 who received IST and were classified as nonresponders at 3 months. Univariate and multivariate logistic regression analysis were used to evaluate factors that could predict the response at 6 months. Results: Univariate analysis showed that the 3-month hemoglobin (HGB) level (P=0.017) , platelet (PLT) level (P=0.005) , absolute reticulocyte count (ARC) (P<0.001) , trough cyclosporine concentration (CsA-C0) (P=0.042) , soluble transferrin receptor (sTfR) level (P=0.003) , improved value of reticulocyte count (ARC(△)) (P<0.001) , and improved value of soluble transferrin receptor (sTfR(△)) level (P<0.001) were related to the 6-month response. The results of the multivariate analysis showed that the PLT level (P=0.020) and ARC(△) (P<0.001) were independent prognostic factors for response at 6 months. If the ARC(△) was less than 6.9×10(9)/L, the 6-month hematological response rate was low, regardless of the patient's PLT count. Survival analysis showed that both the 3-year overall survival (OS) [ (80.1±3.9) % vs (97.6±2.6) %, P=0.002] and 3-year event-free survival (EFS) [ (31.4±4.5) % vs (86.5±5.3) %, P<0.001] of the nonresponders at 6 months were significantly lower than those of the response group. Conclusion: Residual hematopoietic indicators at 3 months after IST are prognostic parameters. The improved value of the reticulocyte count could reflect whether the bone marrow hematopoiesis is recovering and the degree of recovery. A second treatment could be performed sooner for patients with a very low ARC(△).

[Characteristics of bone marrow compensatory erythropoiesis in hereditary spherocytosis].

Objective: To reveal the compensatory features of bone marrow (BM) erythropoiesis in hereditary spherocytosis (HS) and to explore the effect of diferent hemoglobin levels on this compensation. Methods: Clinical and laboratory data of patients with HS were collected, and the peripheral blood absolute reticulocytes counts value was taken as the surrogate parameter to evaluate the ability of erythropoiesis compensation. BM erythropoiesis compensation in HS with diferent degrees of anemia were evaluated. Results: ①Three hundred and two patients were enrolled, including 115 with compensated hemolytic disease, 74 with mild anemia, 90 with moderate anemia, and 23 with severe anemia. ②Hemoglobin (HGB) was negatively correlated with serum erythropoietin in the decompensated hemolytic anemia group (EPO; rs=-0.585, P<0.001) . ③The median absolute reticulocyte count (ARC) of HS patients was 0.34 (0.27, 0.44) ×10(12)/L, up to 4.25 times that of normal people. The maximum ARC was 0.81×10(12)/L, about 10 times that of normal people. The median ARC of patients with compensated hemolytic disease was 0.29 (0.22, 0.38) ×10(12)/L, up to 3.63 times that of normal people. The median ARC of patients with hemolytic anemia was 0.38 (0.30, 0.46) ×10(12)/L, which was significantly higher than the patients with compensated hemolytic disease, up to 4.75 times that of normal people (z=4.999, P=0.003) . ④ ARC was negatively correlated with HGB in the compensated hemolytic disease group (rs=-0.177, P=0.002) and positively correlated with HGB in the decompensated hemolytic anemia group (rs=0.191, P=0.009) . There was no significant difference in the ARC among patients with mild, moderate, and severe anemia (χ(2)=4.588, P=0.101) . ⑤The median immature reticulocyte production index of the mild, moderate, and severe anemia groups was 13.1% (9.1%, 18.4%) , 17.0% (13.4%, 20.8%) , and 17.8% (14.6%, 21.8%) , respectively; the mild anemia group had lower index values than the moderate and severe anemia groups (P(adj) values were both<0.05) , but there was no significant difference between the latter groups (P(adj)=1.000) . The median immature reticulocyte count of patients in the mild, moderate, and severe groups was 5.09 (2.60, 7.74) ×10(10)/L, 6.24 (4.34, 8.83) ×10(10)/L, and 7.00 (3.07, 8.22) ×10(10)/L, respectively; there was no significant difference among the groups (χ(2)=3.081, P=0.214) . Conclusion: HGB can be maintained at a normal level through bone marrow erythropoiesis, while red blood cells are reduced in HS. However, once anemia develops, the bone marrow exerts its maximum erythropoiesis capacity and does not increase, regardless of anemia aggravation or serum EPO increase.

Molecular cloning, tissue expression and association of porcine NR4A1 gene with reproductive traits.

Nuclear receptor subfamily 4, group A, member 1 (NR4A1), other aliase NGFI-B, is an immediate-early gene that encodes an orphan nuclear receptor, which play a potential role in the ovulatory process. In this study, a 4,870 bp fragment covered the complete coding region (CDS) and its unique intron sequences of porcine NR4A1 gene was obtained. The reverse transcriptase-polymerase chain reaction (RT-PCR) indicated that NR4A1 was highly expressed in ovary, uterus, kidney, heart but at very low level in oviduct and not expressed in other tissues. Compared the sequence of CDS and its unique intron of Large White and Meishan pigs, a A/G mutation in intron 5 was found and a PCR-Dde1-RFLP genotyping assay was developed. Association of the SNP and litter size was assessed in two populations [purebred Large White and an experimental synthetic Line (DIV) sows]. Statistical analysis demonstrated that, in the first parity, AG animals in experimental synthetic Line (DIV) sows had 1.805 more piglets born compared to the GG animals (P<0.05). For all parities, in the purebred Large White pigs, those with the GG genotype had an additional 0.877 piglets born and 0.780 piglets born alive compared to the AA animals (P<0.05), those with the AG genotype had additional 0.780 piglets born compared to the AA animals (P<0.05). In addition, significant additive effect of 0.438±0.182 piglets/litter and 0.368±0.165 piglets/litter on piglets born and piglets born alive were detected in the purebred Large White lines (P<0.05), respectively. Therefore, NR4A1 gene was significantly associated with litter size in two populations and could be a useful molecular marker in selection for increasing litter size in pigs.

Real-time reverse transcription-PCR expression profiling of porcine troponin I family in three different types of muscles during development.

In this study, the expression profiling of three troponin I isoforms (TNNI1, TNNI2 and TNNI3) was investigated in two pig breeds differing in muscularity (Yorkshire and Meishan) at six stages (fetal 60 days and postnatal 3, 35, 60, 120, and 180 days) and three types of muscles (longissimus dorsi muscle, LD; semitendinosus, ST; cardiac muscle, CM) using relative real-time quantitative PCR. Significant differences of troponin I expression in three muscles were found between Yorkshire and Meishan breeds at some stages. The expression peak of TNNI1 and TNNI2 in LD and ST was at postnatal 35 or 60 days in Yorkshire and at postnatal 120 or 180 days in Meishan pigs, while it occurred in CM at postnatal 3 days in two pig breeds. The relative expression values of TNNI1 and TNNI2 were significantly higher in LD than ST at most of stages after birth. The expression ratio of TNNI2 versus TNNI1 favoured TNNI2 expression in ST and LD, but on the contrary in CM. The expression peak of TNNI3 occurred at postnatal 60 and 120 days in Yorkshire and Meishan pigs, respectively. TNNI1 and TNNI3 were co-expressed in CM during the fetal and earlier stages after birth.

A SNP in the miR-27a gene is associated with litter size in pigs.

MicroRNAs (miRNAs) are 20-25 nt, endogenous non-coding RNA molecules that act by binding to the complementary sequence of target messenger RNAs. Many evidences showed that miRNAs were involved in the process of germ proliferation and differentiation. In the present study, miR-27a gene was selected as a candidate gene for litter size due to its biological function, its location near a mummified pigs QTL, and its differentially expressed profile in Large White and Chinese Erhualian PMSG-hCG stimulated preovulatory ovaries. By comparative sequencing of miR-27a gene in Large White and Chinese Meishan pigs, one SNP (T/C) which created an additional HpaII site was detected. Then associations of this SNP with litter size traits were assessed in Large White (n=142) and DIV (n=140) pig populations. The statistical analysis demonstrated that AA differed from AB (P<0.01) and BB (P<0.05) for total number of piglets born in the first parities, and also differed from AB (P<0.01) for the number of piglets born alive in all parities (P<0.05) in DIV pigs. No significant difference was observed between different genotypes in Large White pigs.

Molecular characterization, expression pattern and association analysis of the porcine BTG2 gene.

B-cell translocation gene 2 (BTG2), a member of the B-cell translocation gene family with anti-proliferative properties, have been characterized to be involved in cell growth, differentiation and survival. In this study, we cloned the full length sequences of cDNA and genomic DNA of BTG2 gene from the porcine skeletal muscle. Spatial expression analysis showed that the porcine BTG2 gene is expressed predominantly in muscle. Temporal expression analysis in longissimus dorsi muscle demonstrated that the expression of BTG2 gene has the highest expression at 60 days old in Large White while with a peak expression at 120 days old in Meishan. Temporal analysis also revealed that the expression of BTG2 gene is generally higher in Large White than in Meishan at all the developmental stages tested (65 days of conception and 3, 35, 60, 120, and 180 days of postnatal). A single nucleotide polymorphism (G417C) in the intron of BTG2 gene was then detected by PCR-RFLP in Large White × Meishan F2 resource population and association analysis suggested that this polymorphic site had significant association (P < 0.05) with the buttock fat thickness, fat percentage, lean muscle percentage, ratio of lean to fat and carcass length.

Detection of novel SNPs and mapping of the fatness QTL on pig chromosome 7q1.1-1.4 region.

Many QTLs for fatness traits have been mapped on pig chromosome 7q1.1-1.4 in various pig resource populations. Eight novel markers, including seven SNPs and one insertion or deletion within BTNL1, COL21A1, PPARD, GLP1R, MDFI, GNMT, ABCC10, and PLA2G7 genes, as well as two previously reported SNPs in SLC39A7 and HMGA1 genes, were genotyped in Large White and Meishan pig breeds. Except for two SNPs in HMGA1 and ABCC10 genes, allele frequencies of the other eight markers are highly significant different between Chinese indigenous Meishan breeds and Large White pig breeds. Eight polymorphic sites were then used for linkage and QTL mapping to refine the fatness QTL in a Large White × Meishan F(2) resource population. Five chromosome-wise significant QTLs were detected, of which the QTLs for leaf fat weight, backfat thickness at 6-7th rib and rump, and mean backfat thickness were narrowed to the interval between PPARD and GLP1R genes and the QTL for backfat thickness at thorax-waist between GNMT and PLA2G7 genes on SSC7p1.1-q1.4.

Identification of three novel SNPs and association with carcass traits in porcine TNNI1 and TNNI2.

In this study, two novel SNPs (EU743939:g.5174T>C in intron 4 and EU743939:g.8350C>A in intron 7) in TNNI1 and one SNP (EU696779:g.1167C>T in intron 3) in TNNI2 were identified by PCR-RFLP (PCR restriction fragment length polymorphism) using XbaI, MspI and SmaI restriction enzyme, respectively. The allele frequencies of three novel SNPs were determined in the genetically diverse pig breeds including ten Chinese indigenous pigs and three Western commercial pig breeds. Association analysis of the SNPs with the carcass traits were conducted in a Large White × Meishan F(2) pig population. The linkage of two SNPs (g.5174T>C and g.8350C>A) in TNNI1 gene had significant effect on fat percentage. Besides these, the g.5174T>C polymorphism was also significantly associated with skin percentage (P < 0.05), shoulder fat thickness (P < 0.05) and backfat thickness between sixth and seventh ribs (P < 0.05). The significant effects of g.1167C>T polymorphism in TNNI2 gene on fat percentage (P < 0.01), lean meat percentage (P < 0.05), lion eye area (P < 0.05), thorax-waist backfat thickness (P < 0.01) and average backfat thickness (P < 0.05) were also found.

Association of 3 polymorphisms in porcine troponin I genes (TNNI1 and TNNI2) with meat quality traits.

The contractile protein troponin I (TnI), a constituent protein of the troponin complex located on the thin filaments of striated muscle, is involved in inhibition of calcium-induced myosin ATPase activity (and thus contraction). TnI-slow (slow-twitch skeletal muscle isoform, named TNNI1) and TnI-fast (fast-twitch skeletal muscle isoform, named TNNI2) are muscle-fiber-type-specific proteins, and expression of their genes may affect the composition of muscle fiber, thereby influencing the meat quality traits. Thus, the TnI genes are potential candidate genes for traits related to meat quality in animals. Association of 2 SNPs (EU743939:g.5174T>C in intron 4, and EU743939:g.8350C>A in intron 7) of the TNNI1 gene and a SNP (EU696779:g.1167C>T in intron 3) of the TNNI2 gene with 11 meat quality traits were studied on 334 Large White x Meishan F(2) pigs. In the TNNI1 gene, g.5174T>C and g.8350C>A were found to be significantly associated with intramuscular fat content and meat color value of biceps femoris. The g.5174T>C also showed significant effects on meat color value and marbling score of longissimus dorsi, as well as pH of longissimus dorsi and semispinalis capitis. The g.1167C>T polymorphism in the TNNI2 gene affected significantly the pH of longissimus dorsi, meat color value of longissimus dorsi and semispinalis capitis, marbling score of longissimus dorsi, and intramuscular fat.