Genetic diversity of Chinese native pigs inferred from protein electrophoresis

We examined protein polymorphism of 20 native pig breeds in China and 3 introduced pig breeds. Thirty loci have been investigated, among which six loci were found to be polymorphic. Especially, the polymorphism of malate dehydrogenase (MDH), adenylate kinase (AK), and two new alleles of adenosine deaminase (ADA) had not been reported in domestic pigs and wild pigs. The percentage of polymorphic loci (P), the mean heterozygosity (H), and the mean number of alleles (A) are 0.200, 0.065, and 1.300, respectively. The degree of genetic variability of Chinese pigs as a whole was higher than that of goats, lower than that of cattle and horses, and similar to that of sheep. Using the gene frequencies of the 30 loci, Nei's genetic distance among the 20 native breeds in China and 3 introduced pig breeds was calculated by the formula of Nei. The program NEIGHBOR in PHYLIP 3.5c was chosen to construct an UPGMA tree and a NJ tree. Our results show that, of the total genetic variation found in the native pig breeds in China, 31% (0.31) is ascribable to genetic differences among breeds. About 69% of the total genetic variation is found within breeds. Most breeds are in linkage disequilibrium. The patterns of genetic similarities between the Chinese native pig breeds were not in agreement with the proposed pig type classification.

Population phylogenomic analysis of mitochondrial DNA in wild boars and domestic pigs revealed multiple domestication events in East Asia

Background: Previously reported evidence indicates that pigs were independently domesticated in multiple places throughout the world. However, a detailed picture of the origin and dispersal of domestic pigs in East Asia has not yet been reported. Results:

THE ORIGIN AND GENETIC DIFFERENTIATION OF NATIVE BREEDS OF PIGS IN SOUTHWEST CHINA - AN APPROACH FROM MITOCHONDRIAL-DNA POLYMORPHISM

Mitochondrial DNA (mtDNA) of six breeds of native domestic pigs from Yunnan province, southwest China, and two wild boars obtained from Sichuan, China, and Vietnam was analyzed using 20 restriction endonucleases that recognize six nucleotides. Restriction maps were made by double-digestion methods and polymorphic sites were located on the map. According to their mtDNA restriction types, all the breeds were classified into six groups. Genetic distances among groups were calculated to define their phylogenetic relationships. The relationship between the Sichuan wild boar and domestic pigs is close, while the Vietnamese wild boar is relatively far from them, so the domestic pigs in southwest China are likely to have originated from a wild pig which distributed in west China. We compare our results with previous reports in literature and discuss the relationship among Chinese pigs, Japanese pigs, and European pigs. The mtDNA cleavage pattern of the Mingguang pig digested by EcoRV was identical to that of Duroc; mutations at the EcoRI site, detected in the mtDNA of two Dahe pigs, are the same as in the Vietnamese wild boar, suggesting that mutational hot spots exist in the mtDNA of pigs.

Acute rejection is associated with antibodies to non-Gal antigens in baboons using Gal-knockout pig kidneys

We transplanted kidneys from alpha 1,3-galactosyltransferase knockout (GalT-KO) pigs into six baboons using two different immunosuppressive regimens, but most of the baboons died from severe acute humoral xenograft rejection. Circulating induced antibodies to non-Gal antigens were markedly elevated at rejection, which mediated strong complement-dependent cytotoxicity against GaIT-KO porcine target cells. These data suggest that antibodies to non-Gal antigens will present an additional barrier to transplantation of organs from GaIT-KO pigs to humans.

新生豚鼠高胆红素血症时P50抑制变化的研究

目的:评价新生豚鼠高胆红素血症时P50抑制值[即T/C值(T为实验,C为对照)]的动态变化对神经系统的毒性作用.方法:出生5～7天的新生豚鼠30只,随机分成5组,每组6只.其中,第一组为正常对照组(C),其余4组为实验组(T).5组新生豚鼠均在硫喷妥钠麻醉下行颅骨电极包埋术,待手术麻醉清醒后,分别测各组新生豚鼠的T/C值.检测完毕,分别向其中2组实验组动物腹腔注入胆红素溶液100 μg/g,4 h、8 h后观察;另2组实验组动物腹腔注入胆红素溶液200 μg/g,4 h、8 h后观察.正常对照组动物均向腹腔注入生理盐水0.5 ml.各组动物在观察完行为学变化和T/C值检测后,再迅速处死动物,取脑组织,在光镜、电镜下观察脑组织结构的变化.结果:实验豚鼠在注入胆红素溶液后,除Tlb组变化不明显外(P＞0.05),其余各组豚鼠T/C值的变化差异均有统计学意义(P＜0.01).不同实验组与正常对照组的T/C值的变化差异也均有统计学意义(P＜0.01).结论:P50抑制(T/C)在高胆红素血症不同时段均有明显变化,可以较早期地(在胆红素聚集阶段)预测胆红素对神经系统的毒性作用,为临床预防和评价高胆红素血症对新生儿神经系统损伤提供一种新的方法.

Improved suppression of circulating complement does not block acute vascular rejection of pig-to-rhesus monkey cardiac transplants

At present, acute vascular rejection (AVR) remains a primary obstacle inhibiting long-term graft survival in the pig-to-non-human primate transplant model. The present study was undertaken to determine whether repetitive injection of low dose Yunnan-cobra venom factor (Y-CVF), a potent complement inhibitor derived from the venom of Naja kaouthia can completely abrogate hemolytic complement activity and subsequently improve the results in a pig-to-rhesus monkey heterotopic heart transplant model. Nine adult rhesus monkeys received a heterotopic heart transplant from wild-type pigs and the recipients were allocated into two groups: group 1 (n = 4) received repetitive injection of low dose Y-CVF until the end of the study and group 2 (n = 5) did not receive Y-CVF. All recipients were treated with cyclosporine A (CsA), cyclophosphamide (CyP) and steroids. Repetitive Y-CVF treatment led to very dramatic fall in CH50 and serum C3 levels (CH50 < 3 units/C3 remained undetectable throughout the experiment) and successfully prevented hyperacute rejection (HAR), while three of five animals in group 2 underwent HAR. However, the continuous suppression of circulating complement did not prevent AVR and the grafts in group 1 survived from 8 to 13 days. Despite undetectable C3 in circulating blood, C3 deposition was present in these grafts. The venular thrombosis was the predominant histopathologic feature of AVR. We conclude that repetitive injection of low dose Y-CVF can be used to continuously suppress circulating complement in a very potent manner and successfully prevent HAR. However, this therapy did not inhibit complement deposition in the graft and failed to prevent AVR. These data suggest that using alternative pig donors [i.e. human decay accelerating factor (hDAF)-transgenic] in combination with the systemic use of complement inhibitors may be necessary to further control complement activation and improve survival in pig-to-non-human primate xenotransplant model.

Characterization of the porcine differentially expressed PDK4 gene and association with meat quality

To investigate the differential expression of genes in the skeletal muscle between Yorkshire and Chinese indigenous breed Meishan pigs, suppression subtractive hybridization was carried out and many genes were proved to be expressed significantly different in the two breeds. One gene highly expressed in Meishan but lowly expressed in Yorkshire specific library, shared strong homology with human pyruvate dehydrogenase kinase 4 (PDK4). Using semi-quantity and quantity PCR, We confirmed its differential expression between the two breeds. Temporal and spatial expression analysis indicated that porcine PDK4 gene is highly expressed in skeletal muscle and the highest in neonatal pigs. Complete cDNA cloning and sequence analysis revealed that porcine PDK4 gene contains an open reading frame of 1,221 bp. The deduced amino acid sequence showed conservation in evolution. A G/A mutation in intron 9 was identified and association analysis showed that it was significantly associated with intramuscular fat, muscle water content.

猪的起源分化

猪形亚目 (Suiformes) 是相对比较原始的偶蹄类，现生物种有3 个科：河马科 （Hippopotamidae），西猯科（Tayassu）和猪科（Suidae）。虽然猪类是分布最广泛、 适应性最强、最为昌盛的哺乳动物之一，但猪形亚目各物种的系统发育关系目前 研究很少，各成员之间的系统发育关系尚待解决，如河马的分类地位与系统发育 关系就一直存在争议。家养动物在人类早期农业文明的发展中起着重要作用，因 而对家养动物的驯化与扩散的研究受到国际学术界的广泛关注。动物考古学和以 往线粒体DNA 的研究认为家猪有多个驯化中心存在。但较为确切的驯化地点、驯 化发生的时间以及扩散模式仍不清楚。 本研究测定了来自全国各地及东南亚、印度的567 头家猪和159 头欧亚野猪、 马来半岛野猪及非洲疣猪、红河猪线粒体基因组的部分或全部DNA 序列，同时分 析了所有GenBank 中已发表的野猪属线粒体DNA 序列；对猪形亚目各物种的系 统发育关系进行了探讨，构建了基于线粒体DNA 全序列的系统发育关系树，对系 统发育关系树各类群进行了系统的命名和界定，并将所有亚洲野猪和家猪线粒体 DNA 序列进行了单倍型类群的划分，采用平均突变距离法计算了各类群的溯祖时 间，由中性检验和核苷酸错配分布分析群体动态，进而分析野猪和家猪的系统地 理变异模式，从中推断野猪的系统地理分化和家猪的驯化地点、时间以及扩散模 式等群体历史事件。具体得到如下结果： 1. 河马与反刍类形成姐妹群的关系。然后河马和反刍类与猪形亚目的其它 类群形成姐妹群。猪科非洲物种间也是姐妹群的关系。鹿猪是猪科中最 早分化出来的。在野猪属中，爪哇野猪种组和欧亚野猪种组各聚为一支， 为姐妹群的关系。 2. 野猪属(Sus)起源于西瓦利克山脉，起初的扩张产生了野猪属各种组，有 一支扩散到远至苏拉威西岛屿后被长期隔离，形成印尼野猪。随后欧亚 野猪的扩张，产生分布于欧洲的E 类群，中东地区的M 类群和广泛分 布于东亚大陆及其附近岛屿的A 类群；中性检验和核苷酸错配分布显示 这次产生的A 类群后来也发生了多次群体扩张事件。但是马来半岛和东 南亚岛屿没有A 类群分布，而印度也只有古老的A*类群分布，这表明东亚类群A 主要是向东向北扩散。除了在人类饲养中发生的家猪的群体 扩张事件外，A 类群野猪最近的一次扩张事件是发生在约43,000 年前的 D1 类群的扩张，扩张路线主要是向东，直到东北和西伯利亚东南部， 中国西北地区没有D1 类群野猪分布；这一次扩张使D1 类群在整个野 猪群体中占据了主要地位，使得后来野猪的驯化主要发生在D1 类群。 而倒数第二次扩张则是发生在约60,000 年前的D 类群，从而产生了D1、 D2、D3、D4 和可能的新类群，这次扩张的范围要比最近一次扩张的范 围大，东至日本岛屿，北至西北地区都有分布，台湾和海南的野猪主要 是这次扩张过去的。总体上，野猪属内各物种及亚种的地理布与其在系 统发育关系树中的位置相对应。 3. 家猪分布在东亚世系中的两端，位于根部类群A*的为澳洲和太平洋岛 屿的返野猪和印度家猪，而广泛分布于亚洲大陆的家猪只出现在最为年 轻的世系D 中。澳大利亚和太平洋岛屿的返野猪均起源于泛印支那地 区，不支持太平洋岛屿返野猪独立驯化的观点。世系D 的亚类群D2、 D3 和D4 中的家猪主要分布于云南、印度和印支那。D1 类群中既有泛 印支那地区的优势亚类群也有长江流域的优势亚类群。日本古老DNA 不但分布于D1 类群，而且在D3、D*类群以及更古老的类群中均有分 布。总之，亚洲家猪主要起源于由印度东北、孟加拉、印支那北部和云 南南部这样一个湄公河流域，其它地方如中国长江流域和日本也可能发 生了有限的驯化事件。可能的驯化时间大约为12,000 年左右。家猪在中 国的扩散主要由云南向北经四川到达西北地区，向东达长江流域，而长 江流域是另一个区域性扩散中心，是东北亚家猪的主要来源。

Influence of Hypericum perforatum Extract on Piglet Infected with Porcine Respiratory and Reproductive Syndrome Virus

To study the influence of Hypericum perforatum extract (HPE) on piglets infected with porcine respiratory and reproductive syndrome virus (PRRSV), enzyme-labeled immunosorbent assay (ELISA) and cytopathic effect (CPE) were used to determine in vitro whether HPE could induce swine pulmonary alveolar macrophages (PAMs) to secrete IFN-gamma, and whether PRRSV titers in PAMs were affected by the levels of HPE-induced IFN-gamma. HPE (200 mg kg(-1)) was administrated by oral gavage to piglets infected with the PRRSV in vivo to observe whether HPE affected the viremia, lung viral titers, and weight gain of piglets infected with PRRSV. The results showed that HPE was capable of inducing PAMs to produce IFN-gamma in a dose dependent manner and HPE pretreatment was capable of significantly reducing PRRSV viral titers in PAMs (P<0.01). Administration of HPE to the PRRSV-infected animals significantly (P<0.05) reduced viremia over time as compared with the PRRSV-infected animals. But there was not significant decrease in lung viral titers at day 21 post-infection between the HPE-treated animals and the PRRSV-infected control piglets. There were no significant differences in weight gain over time among the HPE-treatment animals, the normal control, and the HPE control animals. The PRRSV-infected animals caused significant (P<0.01) growth retardation as compared with the HPE controls and the normal piglets. It suggested that HPE might be an effective novel therapeutic approach to diminish the PRRSV-induced disease in swine.