中国部分黄牛品种mtDNA遗传多态性研究

对我国8个黄牛品种22个个体的mtDNA D-loop区910bp全序列进行了分析。结果表明：8个黄牛品种D-loop区序列中,A T平均含量为61．65％;经比对,共检测到66个核苷酸多态位点,约占核苷酸总数的7．25％;D-loop全序列突变类型有5种,即转换、颠换、插入、缺失及转换与颠换共存,它们分别占核苷酸多态位点的81．82％、6．06％、7．57％、3．03％及1．52％。以欧洲牛mtDNA D-loop全序列为标准,8个黄牛群体D-loop的平均核苷酸变异率分3个层次：西镇牛、蒙古牛、黑白花牛及秦川牛的核苷酸变异率最低,分别为0．37％、0．44％、0．52％和0．66％;南阳牛与郏县红牛的核苷酸变异率居中,分别为1．91％和2．02％;晋南牛与岳阳牛的核苷酸变异率最高,分别为4．47％和4．73％。中国黄牛品种内D-loop区序列歧异度为0．55％～5．39％,品种间序列歧异度为1．21％～6．59％。在所测黄牛个体中,mtDNA D-loop序列由19种单倍型组成,单倍型比例为86．36%,说明中国黄牛mtDNA遗传多态性很丰富。由此构建了中国8个黄牛品种的NJ分子系统树,聚类分析表明：所测黄牛的mtDNA D-loop序列表现为3个单倍型组,从而揭示中国黄牛可能有3个母系起源,以普通牛起源和瘤牛起源为主。     

中国17个黄牛品种mtDNA变异特征与多态性分析

中国黄牛品种资源丰富,尚有28个地方固有品种.为了进一步深入了解这些宝贵遗传资源,本研究通过mtDNA变异特征与多态性分析揭示这些来自中国不同地域地方黄牛的母系起源与分子系统学特征.在17个品种84个体的mtDNA D-loop全序列中,一共检测到了102个核苷酸替代突变位.由此定义的53个单倍型被类聚为2个明显的单倍群：普通牛和瘤牛.mtDNA D-loop全序列变异的第一个特征是转换发生的频率远高于颠换;第二个特征是缺失与替代突变共存;第三个特征是缺失突变率比较高.所有D-loop全序列的核苷酸多样性和单倍型多样性分别为0.026 78±0.000 50和0.919±0.027.普通牛D-loop单倍型在北方牛种群中占有优势(80%～100%),而瘤牛单倍型在南方牛种群中占有优势(42.9%～100%),2种不同单倍型在中原牛种群中的分布也存在差异.2种不同单倍型在中国不同地域17个黄牛品种中的差异性分布揭示出了瘤牛mtDNA基因在中国黄牛中自南而北、由高到低的流动模式,这种基因流动模式的形成可能是由历史事件、地理隔离以及气候环境差异等造成的.     

贵州黄牛品种间mtDNA的限制性片段长度多态性研究

以１５种限制性内切酶,用限制性片段长度多态方法分析了贵州黄牛４个地方品种和１个育成品种－贵州黑白花奶牛的ｍｔＤＮＡ多态性。发现贵州黄牛有两种类型ｍｔＤＮＡ分子,即普通黄牛类型和瘤牛类型,两者的频率分别是４４．０７％和５５．９３％,没有发现重组和中间类型。贵州黑白花奶牛的ｍｔＤＮＡ与贵州黄牛类似。贵州黄牛可能起源于普通牛和瘤牛。此外,根据品种间亲缘关系的推断,对“盘江黄牛”和“巫陵黄牛”两个品种的命     

海南黄牛和徐闻黄牛线粒体DNA的多态性及其品种分化关系

本文以ＡｐａⅠ、ＡｖａⅠ、ＢａｍＨⅠ、ＢｇｌⅠ、ＢｇｌⅡ、ＤｒａⅠ、ＥｃｏＲⅠ、ＥｃｏＲⅤ、ＨｉｎｄⅢ、ＨｐａⅠ、ＰｓｔⅠ、ＳａｌⅠ、ＳｃａⅠ和ＸｈｏⅠ等１４种限制性内切酶分析来自海南岛的海南黄牛和雷州半岛的徐闻黄牛的线粒体ＤＮＡ限制性片段长度多态性（ｍｔＤＮＡＡＲＦＬＰ）。结果只有一种限制性内切酶（ＳａｌⅠ）在海南黄牛中检测到多态性,并且其中的Ｃ型（１５．０,１．３）尚未见报道。我们的结果还显示,两个品种６个个体的ｍｔＤＮＡ基因单倍型全部表现为Ａ型,即瘤牛的血统。徐闻黄牛和海南黄牛ｍｔＤＮＡ极低的遗传变异度表明两个品种的亲缘关系很近,从而在分子生物学水平为其合称为雷琼黄牛提供了佐证。     

中国荷斯坦牛和鲁西黄牛mtDNAD-loop序列多态性分析

为了从母系遗传角度深入阐明中国荷斯坦牛和鲁西黄牛的群体遗传多样性以及起源进化,本研究采用PCR测序法测定了9头中国荷斯坦牛和11头鲁西黄牛的线粒体DNA D-loop区的部分序列,并经剪切后进行生物信息学软件分析.结果表明,20个个体D-loop区共711 bp,共检测到19种单倍型和50个多态位点.核苷酸多样性(Pi)为0.021 33±0.004 54,单倍型多样性(Hd)为0.994±0.019,平均核苷酸差异数(k)为15.146 20.构建的NJ网络进化树共分为两大支系,其中部分鲁西黄牛与瘤牛聚为一支,而中国荷斯坦牛和部分鲁西黄牛与普通黄牛聚为一支.说明中国荷斯坦牛和鲁西黄牛群体遗传多样性均较高;鲁西黄牛同时含有瘤牛和普通黄牛的血统,而中国荷斯坦牛只含有普通黄牛的血统.     

中国黄牛品种多样性及其保护

总结关于中国黄牛起源和品种多样的文献,依据头颅骨分类,毛色,血液蛋白多态性,体型体态,梁色体组型,线粒体DNA和考古论证的资料可知,在各地的牛种中,中国的无峰牛来自于两种原牛,在长城以北有长角型的普通牛的分支土雷诺蒙古利亚（truano-mognolia)和青藏高原有矮型的短角型普通牛（draft pimigenius),有峰牛来自于三种原牛,来自北非,西亚的瘤牛,印度瘤牛和东南亚瘤牛,这些牛的后裔大多以混血种形态存在,关中和中原地区牛受西亚瘤牛的影响,胸垂较发达,多皱折,体格圈套 ,云南部分高峰牛受印度瘤牛影响,东南地区高峰牛为古代准牛属爪哇牛被东南亚瘤牛吸收杂交的后裔,属矮小型,体躯体而皱折贫乏,肩峰属头位,耳端较尖而不下垂,在起源上,藏牛为原始种,海南高峰牛（zebu sinsis)为一个瘤牛的发源地,云南高峰牛是一个特殊种,击阳牛是含有非洲瘤牛血淮的特殊种,全国的黄牛在总体上可分为两大系统三大类型,根据体态特征分为无峰,低身和有峰三种,按地理分布为蒙古,黄淮和长珠三组,现代国民经济发展引进30个外国品种,加速了地方品种的灭绝,本文还提出了农牛保种应以特殊品种和边缘地区以及特有生态区牛种为主要的主张。     

贵州地方黄牛IGF-1基因多态性及生物信息学分析

为分析黄牛IGF-1基因多态性,筛选出对贵州本地黄牛生长性状有显著影响的SNPs位点,本研究以贵州关岭牛、思南牛、威宁牛和黎平牛为试验对象,构建DNA混池,PCR扩增IGF-1基因所有外显子及部分内含子,采用直接测序法检测IGF-1基因多态性,利用生物信息学软件对IGF-1基因进行分析。结果表明:在贵州4个地方牛群体种中,共筛选出3个SNPS,分别为Intron2-A5123G、Exon3-G56419A、Intron3-C56464A,Exon3-G56419A属于同义突变。其中2个SNPS (Intron2-A5123G, Intron3-C56464A)为4个牛种所共有,而Exon3-G56419A突变仅存在黎平牛中。生物信息学分析表明,牛IGF-1编码蛋白为分泌蛋白,含有信号肽序列,相对分子质量为16 937.68,理论等电点为9.36,且突变前后IGF-1基因m RNA二级结构发生改变,自由能升高,稳定性降低。研究结果显示,4个牛种IGF-1基因具有较高的遗传多样性,可为贵州地方牛种的保种选育提供参考。     

中国黄牛

黄牛（Yellowcatthi）是中国的普通牛种。其在中国的饲养头数在牲畜中或牛类中均居首位,饲养地区几乎遍布全国。在农区主要作役用,半农半牧区役乳兼用,牧区则乳肉兼用。1性状和类型黄牛被毛以黄色为最多,品种可能因此而得名,但也有红棕色和黑色等。头部略粗重,角形不一,角根圆形。体质粗壮,结构紧凑,肌肉发达,四肢强健,蹄质坚实。其体形和性能因自然环境和饲养条件不同而有差异,可分为三大类型。（1）北方黄牛数量最多,分布于华北、东北及西北各地,以蒙古牛、延边牛、复州牛、哈萨克牛等较著名。以肩峰低、垂皮少为主要特征…     

白豆杉的核型和性染色体的研究

白豆杉pseudotaxus chienii(Cheng)Cheng是我国裸子植物特有属之一,雌雄异常,根尖 细胞染色体分析表明：雌株有一对异形性染色体,异配性别,属ZW型;雄株是同配性别,属ZZ型,雌株的型为2n=2x=24=22m(2SAT ZW) 2T,雄株的核型为2n=2x=24=22m(2SAT ZZ) 2T。Giemsa C-带,显示,Z染色体长短臂均具端带,W染色体不显带。     

14.从Cyt b基因全序列分析中国10个黄牛品种的系统进化关系

基于Cyt b基因全长序列,对我国10个地方黄牛品种的遗传多态性和系统发育关系进行了分析.中国黄牛Cyt b基因序列富含碱基A和T,A+T平均含量为56.7%,密码子第3位点核苷酸表现出较强的碱基组成偏倚,该位点上G的含量最低,为 3.5%,而A的含量最高,为44.6%,核苷酸组成偏差指数为0.45.在47个个体1 140 bp的序列中检测到30个变异位点,约占核苷酸总数的2.63%,密码子第3位点的突变率(76.7%)远高于第1位点(16.7%)和第2位点(6.6%),第2位点的非同义替代率(100%)远高于第1位点(40%)和第3位点(4.3%).定义了15种单倍型.将10个品种作为一个大的种群分析时,发现中国黄牛Cyt b基因具有较高的单倍型多样性(Hd=0.783±0046)和一定程度的核苷酸多样性(Pi=0.00828±0.00030),这与中国黄牛地理分布广、种群庞大和起源复杂有关系.基于Kimura 2 parameter距离采用UPGMA法构建的10个黄牛品种分子系统树中将47个个体分别与瘤牛和普通牛聚在一起,说明中国黄牛主要起源于瘤牛和普通牛.北方牛受普通牛的影响较大,南方牛受瘤牛的影响较大,但是对于亲缘关系复杂的中原地区黄牛而言,瘤牛和普通牛对它们的影响力大小因品种而异,因而它们分别和北方牛和南方牛之间的亲缘关系远近程度也存在差异.不同品种之间的亲缘关系差异可能与它们的地理分布差异具有一定的关系.     

黄牛Ag—NOR染色体联合的类型和频率

用银染技术对中国4个黄牛品种（蒙古牛、秦川牛、岭南牛和西镇牛）40头牛的Ag-NOR联合的类型和频率进行了分析。结果表明,黄牛每个体细胞Ag-NOR联合可出现一个、两个或多个、蒙古牛、秦川牛、岭南牛和西镇牛Ag-NOR联合的频率分别为0.135,0.149,0.146和0.153。其中有一个联合的细胞占总的有联合细胞的比率分别为.802,0.891,0.861和0.871。牛Ag-NOR联合的类型可分为链状联合,对称联合,环状联合和堆集联合4种,其中链状联合占60％－70％以上,对称联合占20％－30％。后两种占5％－10A％。经分析表明,Ag-NOR联合的类型和频率可能具有种族特征,而不存在品种差异。     

黄牛Ag-NOR染色体联合的类型和频率

用银染技术对中国4个黄牛品种(蒙古牛、秦川牛、岭南牛和西镇牛)40头牛的Ag-NOR联合的类型和频率进行了分析.结果表明,黄牛每个体细胞Ag-NOR联合可出现一个、两个或多个;蒙古牛、秦川牛、岭南牛和西镇牛Ag-NOR联合的频率分别为0.135、0.149、0.146和0.153.其中有一个联合的细胞占总的有联合细胞的比率分别为0.802、0.891、0.861和0.871.牛Ag-NOR联合的类型可分为链状联合,对称联合,环状联合和堆集联合4种,其中链状联合占60%～70%以上,对称联合占20%～30%.后两种占5%～10%.经分析表明,Ag-N(R联合的类型和频率可能具有种族特征,而不存在品种差异。 Abstract:The type and frequency of Ag-NORs combination of 40 individuals of four native cattle breeds(Mongolian,Qinchuan,Lingnan and Xizhen cattle)in China were analyzed by silver staining technique.The results showed that one,two or more Ag-NORs combinations appeared in metaphase cells of the cattle.The aerage freuency of Ag-NORs combination in each metaphase cell of Mongolian,Qinchuan,Lingnan and Xizhen cattle breeds was 0.135,0.149,0.146 and 0.153 respectively.Four types of Ag-NORs combination:cateniform with frquency 60%～70%,symmetry with 20%～30%,circularity and pile with 5%～10% were observed.The analysis showed that the type and frequency of Ag-NORs combination could perhaps be species characteristics and not breed characteristics.～     

云南黄牛和大额牛的mtDNA多态性研究

本文以mtDNA限制性内切酶片段长度多态技术分析云南牛的mtDNA多态性。结果表明云南黄牛有两种类型的mtDNA分子,一种是普通黄牛类型,另一种是瘤牛类型,两者的频率分别为33%和67%。没有发现过渡型和重组型。昆明黑白花奶牛的mtDNA与云南黄牛的相类似。云南黄牛可能具有两种起源,即普通黄牛起源和瘤牛起源。今天的云南黄牛群体是这两种类型的混合。大额牛的限制性类型与瘤牛相同,表明大额牛的起源与瘤牛有密切关系。     

Chemical and Electron Microscopic Studies of Cattle (Bos taurus) With Four Types of Phenotypic Pigmentation

The biological behavior of the pigmentary phenotypes of four breeds of cattle has been analysed: the black pigmentation of Holstein Friesian; the red pigmentation of Limousin; the dilution in Charolais; and the postnatal disappearance of red pigmentation in Chianina. The analytic techniques included the characterization of melanins by high-performance liquid chromatography, the examination of follicular melanocytes by light microscopy, and the examination of melanosomes by electron microscopy. The black phenotype was very strongly eumelanogenic. The red phenotype in Limousin is polymorphic: individual follicular melanocytes contain both mature eumelanosomes and pheomelanosomes. Charolais and Chianina cattle exhibited a dramatic reduction in melanogenic activity, which was characterized by the almost exclusive presence of prephaoemelanosomes in Charolais and of immature premelanosomes in Chianina. In the dilute Charolais phenotype, the density of distribution of follicular melanocytes also seemed to be reduced. The genes that are responsible for these four phenotypes seem to act on the maturation, differentiation, and density of distribution of the melanosomes.     

Individual Recognition in Domestic Cattle (Bos taurus): Evidence from 2D-Images of Heads from Different Breeds

Background

In order to maintain cohesion of groups, social animals need to process social information efficiently. Visual individual recognition, which is distinguished from mere visual discrimination, has been studied in only few mammalian species. In addition, most previous studies used either a small number of subjects or a few various views as test stimuli. Dairy cattle, as a domestic species allow the testing of a good sample size and provide a large variety of test stimuli due to the morphological diversity of breeds. Hence cattle are a suitable model for studying individual visual recognition. This study demonstrates that cattle display visual individual recognition and shows the effect of both familiarity and coat diversity in discrimination.

Methodology/Principal Findings

We tested whether 8 Prim''Holstein heifers could recognize 2D-images of heads of one cow (face, profiles, ¾ views) from those of other cows. Experiments were based on a simultaneous discrimination paradigm through instrumental conditioning using food rewards. In Experiment 1, all images represented familiar cows (belonging to the same social group) from the Prim''Holstein breed. In Experiments 2, 3 and 4, images were from unfamiliar (unknown) individuals either from the same breed or other breeds. All heifers displayed individual recognition of familiar and unfamiliar individuals from their own breed. Subjects reached criterion sooner when recognizing a familiar individual than when recognizing an unfamiliar one (Exp 1: 3.1±0.7 vs. Exp 2: 5.2±1.2 sessions; Z = 1.99, N = 8, P = 0.046). In addition almost all subjects recognized unknown individuals from different breeds, however with greater difficulty.

Conclusions/Significance

Our results demonstrated that cattle have efficient individual recognition based on categorization capacities. Social familiarity improved their performance. The recognition of individuals with very different coat characteristics from the subjects was the most difficult task. These results call for studies exploring the mechanisms involved in face recognition allowing interspecies comparisons, including humans.     

Novel Features of the Prenatal Horn Bud Development in Cattle (Bos taurus)

Whereas the genetic background of horn growth in cattle has been studied extensively, little is known about the morphological changes in the developing fetal horn bud. In this study we histologically analyzed the development of horn buds of bovine fetuses between ~70 and ~268 days of pregnancy and compared them with biopsies taken from the frontal skin of the same fetuses. In addition we compared the samples from the wild type (horned) fetuses with samples taken from the horn bud region of age-matched genetically hornless (polled) fetuses. In summary, the horn bud with multiple layers of vacuolated keratinocytes is histologically visible early in fetal life already at around day 70 of gestation and can be easily differentiated from the much thinner epidermis of the frontal skin. However, at the gestation day (gd) 212 the epidermis above the horn bud shows a similar morphology to the epidermis of the frontal skin and the outstanding layers of vacuolated keratinocytes have disappeared. Immature hair follicles are seen in the frontal skin at gd 115 whereas hair follicles below the horn bud are not present until gd 155. Interestingly, thick nerve bundles appear in the dermis below the horn bud at gd 115. These nerve fibers grow in size over time and are prominent shortly before birth. Prominent nerve bundles are not present in the frontal skin of wild type or in polled fetuses at any time, indicating that the horn bud is a very sensitive area. The samples from the horn bud region from polled fetuses are histologically equivalent to samples taken from the frontal skin in horned species. This is the first study that presents unique histological data on bovine prenatal horn bud differentiation at different developmental stages which creates knowledge for a better understanding of recent molecular findings.     

Occurrence of the Rumen Ciliate Oligoisotricha bubali in Domestic Cattle (Bos taurus)

Oligoisotricha bubali, previously observed twice in water buffalo, was detected in rumen contents of domestic cattle (Bos taurus) in two different areas of Tennessee. Concentrations ranged from <1 to 35% of the total protozoa in unweaned calves and up to 72% in older animals in feedlot. In contrast to the other genera of holotrichs, both total numbers and percent composition of O. bubali increased when animals were fed a corn silage-concentrate diet.     

Influence of the breed of bull (Bos taurus indicus vs. Bos taurus taurus) and the breed of cow (Bos taurus indicus, Bos taurus taurus and crossbred) on the resistance of bovine embryos to heat

In vitro studies have shown that Bos taurus indicus (B. t. indicus) embryos submitted to heat shock at early stages of development are better able to survive as compared to Bos taurus taurus embryos. Embryo genotype influences resistance to heat shock thus leading to the question as to whether embryos sired by thermo-tolerant breeds exhibit the same resistance to heat shock. In the present study the influence of both oocyte and semen, on the resistance to heat shock (HS) at early stages of in vitro development, was assessed in B. t. indicus [Nelore (N) breed], B. t. taurus [Holstein (H) and Angus (A) breeds] and crossbreds. In Experiment 1, Nelore and crossbred oocytes were collected from slaughterhouse ovaries and fertilized with spermatozoa from Nelore and Angus bulls. Presumptive embryos were collected and randomly assigned to control (39 degrees C) or HS at 12, 48 or 96 h post insemination (hpi; 41 degrees C for 12h) treatments. The cleavage rates and proportion of embryos developing to the blastocyst and hatched blastocyst stages were recorded on Days 2, 8 and 10, respectively. Heat shock treatment decreased development of both Nelore and crossbred embryos. There was a significant interaction between time (12, 48 or 96 hpi) and temperature for blastocyst rates, i.e., the embryos became more thermotolerant as development proceeded. In Experiment 2, oocytes from Nelore and Holstein cows were fertilized with semen from bulls of either Nelore or Angus breeds, and subjected to 12 h HS at 96 hpi. Heat shock at 96 hpi, decreased embryo development. Additionally, cowxtreatment and bullxtreatment interactions were significant for blastocyst rates, i.e., both breed of cow and breed of bull affected the decline in blastocyst rate caused by heat shock treatment. In conclusion, the present results indicate that Nelore embryos (indicus) are more resistant to heat shock than Holstein (taurus) at early stages of in vitro development, and that embryos become more thermo-tolerant as development proceeds. Additionally, the resistance to heat shock was a result of the genetic contribution from both oocyte and spermatozoa.     

Polymorphisms in Blood Proteins of Bos indicus and Bos taurus Cattle Breeds of Cameroon and Nigeria, and Description of New Albumin Variants

Polymorphisms in the five blood protein loci albumin (ALB), carbonic anhydrase (CA II), vitamin D binding protein (GC), haemoglobin (HBB), and transferrin (TF) were investigated in 520 individuals from 12 cattle populations (Bos indicus and Bos taurus) in Cameroon and Nigeria by isoelectric focusing with carrier ampholytes in ultrathin polyacrylamide gels (PAG-IEF) and by linear gradient polyacrylamide gel electrophoresis (PAGE). While all loci in nine populations were polymorphic with up to six alleles at the ALB and TF loci: the Namchi population showed monomorphism at the CA II locus and Muturu at the ALB, CA II, and HBB loci. There was a clear distinction between Bos indicus and Bos taurus breeds at the ALB locus with ALBB predominating in indicine and ALBA predominating in taurtine breeds. CA IIS, GCA, and HBBA were the most commonly occurring alleles in all populations. Two variants not described before were demonstrated by PAG-IEF at the ALB locus and named ALBJ and ALBK. Mean effective number of alleles as measure of intrabreed diversity was higher in zebu populations (2.040-2.288) as compared to taurine breeds (1.349-1.836). Significant deviations from Hardy-Weinberg equilibrium occurred in some populations at the HBB and TF loci. More haplotypes of ALB/GC occurred in the zebu than taurine breeds. ALBAGCA predominated in the taurine populations and ALBBGCA in the indicine populations. Influence of zebu genes on the Namchi and N'Dama taurine breeds was detected at the ALB, CA II, HBB, and TF loci, and estimated at 61.5% and 5.7%, respectively. The high resolution of PAG-IEF in screening for polymorphisms within diversity studies was demonstrated.     

Molecular and Biochemical Evaluation of Indian Draft Breeds of Cattle (Bos indicus)

Glutathione peroxidase-1 (GPX-1) enzyme detoxifies peroxides by reacting with the GSH (reduced glutathione) responsible for the maintenance of the integrity of essential biomolecules. This study was conducted on 100 animals of two Indian draft breeds of cattle (Bos indicus), Nimari, and Malvi. Genomic DNA was isolated from blood samples, and four fragments (80, 71, 78, and 442?bp) of the GPX-1 gene were amplified by polymerase chain reaction. PCR-SSCP analysis in 12% PAGE with silver staining revealed polymorphism in three of the fragments (80, 71, and 442?bp) in these two cattle breeds. Breed differences for the blood biochemical parameters (serum creatine kinase and lactic acid level) and overall draft ability were studied. The genetic polymorphism identified for the GPX-1 gene in this investigation would help in the identification of alleles related to draft capacity in these animals for future genetic improvement.