Phenotypic and genotypic background underlying variations in fatty acid composition and sensory parameters in European bovine breeds

Background： Consuming moderate amounts of lean red meat as part of a balanced diet valuably contributes to intakes of essential nutrients, in this study, we merged phenotypic and genotypic information to characterize the variation in lipid profile and sensory parameters and to represent the diversity among 15 cattle populations. Correlations between fat content, organoleptic characteristics and lipid profiles were also investigated. Methods： A sample of 436 largely unrelated purebred bulls belonging to 15 breeds and reared under comparable management conditions was analyzed. Phenotypic data -including fatness score, fat percentage, individual fatty acids （FA） profiles and sensory panel tests- and genotypic information from 11 polymorphisms was used. Results： The correlation coefficients between muscle total lipid measurements and absolute vs. relative amounts of polyunsaturated FA （PUFA） were in opposite directions. Increasing carcass fat leads to an increasing amount of FAs in triglycerides, but at the same time the relative amount of PUFAs is decreasing, which is in concordance with the negative correlation obtained here between the percentage of PUFA and fat measurements, as well as the weaker correlation between total phospholipids and total lipid muscle content compared with neutral lipids. Concerning organoleptic characteristics, a negative correlation between fiavour scores and the percentage of total PUFA, particularly to n-6 fraction, was found. The correlation between juiciness and texture is higher than with flavour scores. The distribution of SNPs plotted by principal components analysis （PCA） mainly reflects their known trait associations, although influenced by their specific breed allele frequencies. Conclusions： The results presented here help to understand the phenotypic and genotypic background underlying variations in FA composition and sensory parameters between breeds. The wide range of traits and breeds studied, along with the genotypic information on polymorphisms previo     

Historical DNA as a tool to genetically characterize the Mediterranean sand tiger shark (Carcharias taurus,Lamniformes: Odontaspididae): A species probably disappeared from this basin

1. The sand tiger shark (Carcharias taurus) is a coastal species distributed in temperate and sub‐tropical waters, classified as ‘Vulnerable’ at global level and ‘Critically endangered’ in eastern Australia, south‐western Atlantic Ocean, and Mediterranean Sea. Six populations (north‐western Atlantic, Brazil, South Africa, Japan, eastern Australia, and western Australia) with low genetic diversity and limited gene flow were identified worldwide, but genetic information for many other geographic areas are still missing. Specifically, this species is listed in several reports as part of the Mediterranean fauna, even if there has been a lack of catches and sightings in recent years in this basin. To clarify the origin of C. taurus individuals caught in the past in the Mediterranean Sea, historical samples were genetically analysed.
2. Nine samples with certain Mediterranean origin were collected from different European museums. DNA was extracted and ~600 bp of the mitochondrial DNA control region were amplified using eight overlapping species‐specific primer pairs. Sequences obtained were aligned with all the haplotypes globally known so far.
3. Genetic analysis revealed the misidentification of one museum specimen. Among the remaining Mediterranean historical samples, three different haplotypes were recovered. Two of them previously observed only in South Africa and one described in both South African and Brazilian populations.
4. Results suggest a genetic relationship between Mediterranean sand tiger sharks and those from the western Indian Ocean. According to previous studies, we hypothesized that, during the Pleistocene, the cold Benguela upwelling barrier was temporarily reduced allowing the passage of C. taurus individuals from the Indian to Atlantic Ocean. After the restoration of this phylogeographic barrier some individuals were trapped in the Atlantic Ocean and probably migrated northward colonizing the western African coasts and the Mediterranean Sea.

     

牛MyoG基因启动子的克隆与序列分析

根据G enB ank中已公布的人、猪和小鼠的MyoG基因的5′侧翼和部分第一外显子序列设计PCR引物,用touch-dow n PCR技术扩增了牛MyoG基因的启动子序列,构建了重组克隆载体pGEM-T-MyoG,并通过PCR扩增、限制性酶切对阳性克隆进行了鉴定、测序及生物信息学分析。结果表明,牛MyoG基因的启动子序列(G en-bank中注册号为AY 882581)长度为672 bp,其与猪、人和小鼠相应序列的同源性分别为94%,91%和88%,且其在不同物种之间具有一定的保守性。牛MyoG基因启动子的克隆与序列分析为进一步研究牛MyoG基因的表达调控奠定了基础。     

Breeding distribution and maternal genetic lineages in Lulu,a dwarf cattle population in Nepal

Lulu is a dwarf cattle population bred in the Mustang district of western and central Nepal. This area is located around the habitat boundary between Bos taurus and Bos indicus. The peculiarities of Lulu are their small size (weight range in the adult female: 68–153 kg) and rearing in high mountain areas at 2800 m to 4000 m in altitude. There were 5770 head of Lulu cattle in the Mustang district in 1998, 4333 females and 1437 males. The morphological appearance of Lulu is Bos taurus. However, one of the five Lulu studied in Kagbeni, Mustang had a Bos indicus mitochondrial DNA type based on the D‐loop sequence, while the other four were Bos taurus. It is suggested that there are hybrids of Lulu with Bos indicus maternal lineage in a mostly taurine‐breed genetic background. Steps must be taken to preserve the unique Lulu.     

The Agersoe cattle: the last remnants of the Danish island cattle (Bos taurus)?

A phenotypically interesting strain of cattle existed on the small island of Agersoe, on the west coast of Zealand, Denmark, in the beginning of the last decade. The cattle share a great resemblance to the extinct Danish breed, the Island cattle. The objective of this study was to genetically characterize the Agersoe cattle, using microsatellites, amplified fragment length polymorphism (AFLP) and mtDNA markers, and analyse the genetic variability within the breed and the genetic relationship to 14 European breeds with focus on the Red Danish and Jutland breed. The results show diversity in nuclear markers comparable to that of modern breeds and that the Agersoe cattle are separable from the two native breeds. The absence of inbreeding and the degree of genetic diversity are taken as a sign of recent admixture. The Agersoe cattle did not exhibit a consistent association with any of the European breeds. Several arguments based on this survey have been put forward in favour of characterizing the Agersoe cattle as being the last remnants of the Danish Island Cattle.     

Kazakhstani native cattle reveal highly divergent mtDNA from Bos taurus and Bos indicus lineages with an absence of Bos indicus Y chromosome

Kazakhstan is the largest landlocked country and contains two important propagation routes for livestock from the Fertile Crescent to Asia. Therefore, genetic information about Kazakhstani cattle can be important for understanding the propagation history and the genetic admixture in Central Asian cattle. In the present study, we analyzed the complete mtDNA D‐loop sequence and SRY gene polymorphism in 122 Kazakhstani native cattle. The D‐loop sequences revealed 79 mitochondrial haplotypes, with the major haplogroups T and I. The Bos taurus subhaplogroups consisted of T (3.3%), T1 (2.5%), T2 (2.5%), and T4 (0.8%) in addition to the predominant subhaplogroup T3 (86.9%), and the Bos indicus subhaplogroup of I1 (4.1%). Subsequently, we investigated the paternal lineages of Bos taurus and Bos indicus, however, all Kazakhstani cattle were shown to have Y chromosome of Bos taurus origin. While highly divergent mtDNA subhaplogroups in Kazakhstani cattle could be due to the geographical proximity of Kazakhstan with the domestication center of the Fertile Crescent, the absence of Bos indicus Y chromosomes could be explained by a decoupling of the introgression dynamics of maternal and paternal lineages. This genetic information would contribute to understanding the genetic diversity and propagation history of cattle in Central Asia.     

牛体内培育牛黄的研究

 牛黄为我国传统名贵中药材,是牛科动物胆囊或胆管内形成的结石。本文报道了简便易行、适宜于农村推广的育黄技术育黄,22个月平均产黄10.57克/头,最高32.0克/头。并对培育牛黄进行了化学成分分析,结果:除胆红素略低于天然牛黄外,其他各项指标均与天然牛黄相似。药效学试验及毒力试验均表明,培育牛黄与天然牛黄相似。     

牛RECQL解旋酶的原核表达纯化及解旋条件优化

【目的】通过大肠杆菌表达纯化牛(Bos taurus)RECQL蛋白,利用停流光谱技术对解旋条件进行优化,为研究RECQL的酶促反应动力过程奠定基础。【方法】将人工合成的牛RECQL蛋白编码序列与pET21a载体相连接,获得重组表达载体pET21a-BtRecql后,将其导入大肠杆菌BL21(DE3)菌株中进行诱导表达,经过Ni-NTA亲和层析和Superdex 200凝胶过滤层析,得到纯化的重组蛋白BtRECQL;再利用停流光谱技术对BtRECQL解旋过程进行检测分析,通过摸索不同的试验参数找到BtRECQL发挥解旋功能较适宜的条件。【结果】得到了纯度大于95%的BtRECQL蛋白,产量为0.29 mg/L。在BtRECQL浓度为60nmol/L,反应条件为1.0 mmol/L ATP,30mmol/L Tris-HCl,pH 7.5,60mmol/L NaCl,1mmol/L MgCl2,2mmol/L DTT,孵育温度为37℃时,该蛋白解旋活性较好。【结论】成功表达并纯化了BtRECQL蛋白,确定了其最优的解旋条件。     

牛趋化因子受体基因1第2外显子的单核苷酸多态性分析

采用DNA测序、巢氏PCR和CRS-PCR方法对中国荷斯坦牛、鲁西黄牛、渤海黑牛的趋化因子受体基因1(CXCR1)的单核苷酸多态性(SNPs)进行研究,在第2外显子上发现了4个SNPs,分别为291 bp(C/T)、333 bp(C/T)、337 bp(A/G)和365 bp(C/T),这4个位点在中国荷斯坦牛、鲁西黄牛、渤海黑牛群体中均达到中度多态(0.25PIC0.5),优势等位基因分别为C、C、A、C,等位基因频率分别为0.82/0.67/0.65、0.80/0.74/0.71、0.70/0.65/0.82、0.56/0.58/0.56。经χ2适合性检验,渤海黑牛所有位点全部达到Hardy-Weinberg平衡状态;荷斯坦牛在突变位点291 bp(C/T)、333 bp(C/T)和337 bp(A/G)达到Hardy-Weinberg平衡状态;鲁西黄牛仅在365 bp(C/T)位点达到Hardy-Weinberg平衡状态。     

Genomic regions and enrichment analyses associated with carcass composition indicator traits in Nellore cattle

The aim of this study was to estimate genetic parameters and identify genomic regions associated with carcass traits obtained by ultrasound and visual scores in Nellore cattle. Data from ~66,000 animals from the National Association of Breeders and Researchers (ANCP) were used. The variance components for backfat thickness, rump fat thickness and Longissimus muscle area (LMA) were estimated considering a linear model whereas a threshold model for body structure (BS), finishing precocity (FP) and musculature (MS) traits. The SNP solutions were estimated using the ssGBLUP approach by considering windows of 10 consecutive SNPs. Regions that accounted for more than 1.0% of the additive genetic variance were used. Genes identified within the significant windows, such as FOXA3, AP2S1, FKRP, NPASI and ATP6V1G1, were found to be related with MS, while OMA1 and FFGY with BS and FP traits. The PLTP, TNNC2 and GPAT2 genes were found in the regions associated with LMA, as well as TKT, FNDC5 and CHRND can strongly be related with fat deposition. Gene enrichment analysis revealed processes that might be directly influenced the organism growth and development. These results should help to better understand the genetic and physiological mechanisms regulating growth and body composition, muscle tissue development and subcutaneous fat expression, and this information might be useful for future genomic studies in Nellore cattle.