Mitochondrial DNA variation in cattle of South China: origin and introgression

Ten restriction endonucleases were used to investigate the mitochondrial DNA restriction fragment length polymorphism (mtDNA RFLP) of 11 native cattle breeds and one cultivated cattle breed in South China. Twenty-three restriction morphs were detected, which can be sorted into five haplotypes, A phylogenetic tree of the haplotypes was constructed by using the 'upgma' method. Our study showed that haplotype I and II are identical to the zebu (Bos indicus) and taurine (Bos taurus) haplotypes, respectively. Zebu and taurine were the two major origins of cattle populations in South China, and the zebu probably had more influence on the native cattle population than taurine did. Haplotype III is identical to haplotype I of yak (Bos grunniens), which was only detected in the Diqing cattle breed. Haplotype IV was detected for the first time. This haplotype, found only in Dehong cattle, might be from an independent domestication event, probably from another Bos indicus population. Divergence of haplotypes I and IV occurred about 268,000-535 000 years ago, much earlier than the 10,000-year history of cattle husbandry. Our results also suggest a secondary introgression of mtDNA from yak to Diqing cattle.

Genetic diversity and relationship of Yunnan native cattle breeds and introduced beef cattle breeds

In this study, random amplified polymorphic DNA (RAPD) analysis was used to estimate genetic diversity and relationship in 134 samples belonging to two native cattle breeds from the Yunnan province of China (DeHong cattle and DiQing cattle) and four intro

Prion protein gene (PRNP) polymorphisms in native Chinese cattle

Le polymorphisme au sein de quatre regions du gene codant pour la proteine prion bovine (PRNP) confere la susceptibilite a l'encephalopathie bovine spongiforme (BSE). Ceux-ci comprennent un polymorphisme d'insertion/deletion (indel) de 23 pb dans le promoteur, un indel de 12 pb dans l'intron 1, un octapeptide repete ou un indel de 24 pb au sein du cadre de lecture, et un polymorphisme mononucleotidique (SNP) dans la region codante. Dans ce travail, les auteurs ont examine la frequence des genotypes, des alleles et des haplotypes pour ces indel au sein de 349 bovins d'origine chinoise, de meme que la sequence nucleotidique de ce gene chez 50 de ces animaux. Leurs resultats montrent que l'allele ayant la deletion de 12 pb et l'haplotype combinant la deletion de 23 pb et la deletion de 12 pb, lesquels ont ete suggeres comme etant importants pour la susceptibilite a la BSE, sont rares au sein des bovins du sud de la Chine. Une difference significative a ete observee entre les bovins affectes par la BSE et les bovins chinois sains pour ce qui est de l'indel de 12 pb. Au total, 14 SNP ont ete observes dans la region codante du gene PRNP chez les bovins chinois. Trois de ces SNP etaient associes a des changements d'acides amines (K3T, P54S et S154N). La substitution E211K qui a ete rapportee recemment chez un cas atypique de la BSE chez un bovin americain n'a pas ete detectee dans ce travail.

Zebu Cattle Are an Exclusive Legacy of the South Asia Neolithic

Animal domestication was a major step forward in human prehistory, contributing to the emergence of more complex societies. At the time of the Neolithic transition, zebu cattle (Bos indicus) were probably the most abundant and important domestic livestock species in Southern Asia. Although archaeological evidence points toward the domestication of zebu cattle within the Indian subcontinent, the exact geographic origins and phylogenetic history of zebu cattle remains uncertain. Here, we report evidence from 844 zebu mitochondrial DNA (mtDNA) sequences surveyed from 19 Asiatic countries comprising 8 regional groups, which identify 2 distinct mitochondrial haplogroups, termed I1 and I2. The marked increase in nucleotide diversity (P < 0.001) for both the I1 and I2 haplogroups within the northern part of the Indian subcontinent is consistent with an origin for all domestic zebu in this area. For haplogroup I1, genetic diversity was highest within the Indus Valley among the three hypothesized domestication centers (Indus Valley, Ganges, and South India). These data support the Indus Valley as the most likely center of origin for the I1 haplogroup and a primary center of zebu domestication. However, for the I2 haplogroup, a complex pattern of diversity is detected, preventing the unambiguous pinpointing of the exact place of origin for this zebu maternal lineage. Our findings are discussed with respect to the archaeological record for zebu domestication within the Indian subcontinent.

Dissecting the matrilineal components of Tongjiang cattle from Southwest China

Tongjiang cattle are a local cattle population of Sichuan Province, China, numbering approximately half a million in 2005. They have long been grouped into the Bashan breed, although they have a unique breeding history and phenotypic characteristics, as w

利用夏季自然发情的云南黄牛进行奶牛胚胎移植效果研究

利用夏季自然发情的云南黄牛为受体,开展了奶牛体内冷冻胚胎移植.留用的114头受体牛中,本地黄牛59头,年龄在3～10岁,均为经产牛,最终移植27头,西杂牛56头(其中2岁以下的青年牛26头),移植29头(青年牛11头),两个品种受体利用率分别为45.8%和51.8%;移植后妊娠率分别为59.3%和55.2%;解冻的63枚胚胎移植给了56头受体牛,A级胚胎单独移植和B、C级胚胎搭配移植最终妊娠结果分别是58.5%(24/41)和53.3%(8/15);发情后第6 d和第7 d移植妊娠率分别为56%和58.1%.结果表明,1～10岁的西杂牛和3～10岁体型较大的本地黄牛均可作为受体移植奶牛胚胎;利用自然发情的云南黄牛做受体移植效果较为理想,是一种经济、方便、适合云南广大农村推广的技术途径;A级胚胎单独移植和B、C级搭配移植可获得较为理想的妊娠结果;处于发情后第6 d和第7 d的云南黄牛都可以作为桑囊期奶牛胚胎的移植受体.

Vitrification of Yunnan Yellow Cattle oocytes: work in progress

The objective of this study was to provide a simple cryopreservation method for oocytes from Yunnan Yellow Cattle and facilitate preservation efforts in this native Chinese breed, which is threatened by agricultural modernization. Cumulus-oocyte complexes (COCs) were collected from slaughterhouse ovaries and matured in vitro for 22-24 h, then selected for cryopreservation. Vitrification in open pulled straws (OPS) or in microdrops on a cooled metal surface (solid surface vitrification, SSV) was compared. The OPS vitrification solution consisted of 20% ethylene glycol (EG) and 20% DMSO. The SSV solution was a mixture of 35% EG, 5% polyvinyl-pyrrolidon (PVP) and 0.4 M trehalose. Vitrified and warmed oocytes were either fertilized in vitro or parthenogenetically activated. The rates of cleavage and development to blastocysts of fertilized oocytes following OPS versus SSV were not statistically different (38.3 and 12.5% versus 35.8 and 6.0%, respectively). The corresponding rates of parthenogenetic development to blastocysts were also not different (8.2 versus 3.5%, respectively). Development to blastocysts of non-vitrified controls following fertilization was significantly higher than that of the vitrified oocytes (22.6%, P < 0.05). These results demonstrate for the first time, that although both OPS and SSV procedures reduced embryonic development, Yunnan Yellow Cattle oocytes are capable of developing to blastocysts following cryopreservation. (C) 2002 Elsevier Science Inc. All rights reserved.

Developmental potential of vitrified holstein cattle embryos fertilized in vitro with sex-sorted sperm

In vitro fertilization (IVF) is a feasible way to utilize sex-sorted sperm to produce offspring of a predetermined sex in the livestock industry. The objective of the present study was to examine the effects of various factors on bovine IVF and to systema

Genetic diversity and origin of Chinese cattle revealed by mtDNA D-loop sequence variation

To determine the origin and genetic diversity of Chinese cattle, we analyzed the complete mtDNA D-loop sequences of 84 cattle from 14 breeds/populations from southwest and west China, together with the available cattle sequences in GenBank. Our results sh

Regulation of zygotic gene activation in the preimplantation mouse embryo: Global activation and repression of gene expression

Superimposed on the activation of the embryonic genome in the preimplantation mouse embryo is the formation of a transcriptionally repressive state during the two-cell stage. This repression appears mediated at the level of chromatin structure, because it is reversed by inducing histone hyperacetylation or inhibiting the second round of DNA replication. We report that of more than 200 amplicons analyzed by mRNA differential display, about 45% of them are repressed between the two-cell and four-cell stages. This repression is scored as either a decrease in amplicon expression that occurs between the two-cell and four-cell stages or on the ability of either trichostatin A tan inhibitor of histone deacetylases) or aphidicolin tan inhibitor of replicative DNA polymerases) to increase the level of amplicon expression. Results of this study also indicate that about 16% of the amplicons analyzed likely are novel genes whose sequence doesn't correspond to sequences in the current databases, whereas about 20% of the sequences expressed during this transition likely are repetitive sequences. Lastly, inducing histone hyperacetylation in the two-cell embryos inhibits cleavage to the four-cell stage. These results suggest that genome activation is global and relatively promiscuous and that a function of the transcriptionally repressive state is to dictate the appropriate profile of gene expression that is compatible with further development.

Knock down of gfp and no tail expression in zebrafish embryo by in vivo-transcribed short hairpin RNA with T7 plasmid system

A short-hairpin RNA (shRNA) expression system, based on T7 RNA polymerase (T7RP) directed transcription machinery, has been developed and used to generate a knock down effect in zebrafish embryos by targeting green fluorescent protein (gfp) and no tail (ntl) mRNA. The vector pCMVT7R harboring T7RP driven by CMV promoter was introduced into zebrafish embryos and the germline transmitted transgenic individuals were screened out for subsequent RNAi application. The shRNA transcription vectors pT7shRNA were constructed and validated by in vivo transcription assay. When pT7shGFP vector was injected into the transgenic embryos stably expressing T7RP, gfp relative expression level showed a decrease of 68% by analysis of fluorescence real time RT-PCR. As a control, injection of chemical synthesized siRNA resulted in expression level of 40% lower than the control when the injection dose was as high as 2 mu g/mu l. More importantly, injection of pT7shNTL vector in zebrafish embryos expressing T7RP led to partial absence of endogenous ntl transcripts in 30% of the injected embryos when detected by whole mount in situ hybridization. Herein, the T7 transcription system could be used to drive the expression of shRNA in zebrafish embryos and result in gene knock down effect, suggesting a potential role for its application in RNAi studies in zebrafish embryos.

Factors affecting the efficiency of somatic cell nuclear transplantation in the fish embryo

Procedures to improve somatic cell nuclear transplantation in fish were evaluated. We reported effects of nonirradiated recipient eggs, inactivated recipient eggs, different combinations between recipient eggs and donor cells, duration of serum starvation, generation number, and passage number of donor cells on developmental rates of nuclear transplant (NT) embryos. Exposure to 25,000 R of gamma-rays inactivated recipient eggs. Single nucleus of cultured, synchronized somatic cell from gynogenetic bighead carp (Aristichthys nobilis) was transplanted into nonirradiated or genetically inactivated unfertilized egg of gibel carp (Carassius auratus gibelio). There was no significant difference in developmental rate between nonirradiated and inactivated recipient eggs (27.27% vs. 25.71%, respectively). Chromosome count showed that 70.59% of NT embryos contained 48 chromosomes. It showed that most NT embryos came from donor nuclei of bighead carp, which was supported by microsatellite analysis of NT embryos. But 23.53% of NT embryos contained more than 48 chromosomes. It was presumed that those superfluous chromosomes came from nonirradiated recipient eggs. Besides, 5.88% of NT embryos were chimeras. Eggs of blunt-snout bream (Megalobrama amblycephala) and gibel carp were better recipient eggs than those of loach (Misgurnus anguillicaudatus) (25% and 18.03% vs. 8.43%). Among different duration of serum starvation, developmental rate of NT embryos from somatic nuclei of three-day serum starvation was the highest, reaching 25.71% compared to 14.14% (control), 20% (five-day), and 21.95% (seven-day). Cultured donor cells of less passage facilitated reprogramming of NT embryos than those of more passage. Recloning might improve the developmental rate of NT embryos from the differentiated donor nuclei. Developmental rate of fourth generation was the highest (54.83%) and the lowest for first generation (14.14%) compared to second generation (38.96%) and third generation (53.01%). (C) 2002 Wiley-Liss, Inc.

The toxic effects of microcystin-LR on embryo-larval and juvenile development of loach, Misguruns mizolepis Gunthe

Microcystin-LR, a specific and potent hepatotoxin, was tested for its effects oil loach embryo-larval and juvenile development, The results of this study showed that loach embryos were more sensitive when exposed to microcystin-LR at a later than at an earlier stage of development, Juveniles were far less sensitive to MC-LR than were embryos and larvae. Mortality and developmental abnormality were proven to be dose-dependent and to be stage-specific sensitive. Among the abnormal changes noted were: pericardial edema and tubular heart, bradycardia, homeostasis, poor yolk resumption. small head, curved body and tail, and abnormal hatching, Liver and heart were the main targets of microcystin-LR toxicity. Ultrastructural analysis documented a complex set of sublethal effects of microcystin-LR on loach hepatocytes, chiefly including morphological alteration in nuclear and RER of loach liver cells. fit addition, microcystin-LR was lethal to loach juvenile in the subacute (7 days) exposure (LC50) = 593.3 mug/l). (C) 2002 Elsevier Science Ltd. All rights reserved.