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 of cattle in South China as revealed by blood protein electrophoresis

Genetic variation of 31 blood protein loci in 236 cattle from eight South China populations (including mithan, Bos frontalis) and a Holstein population was investigated by means of horizontal starch gel electrophoresis. Thirteen loci (ALB, CAR, Hb-b, Np, PGM, Amy-I, PEP-B, AKP, 6PGD, Cp, Pa, EsD, and TF) were found to be polymorphic. The comparison of average heterozygosities (H) shows that all the native cattle embrace a rich genetic diversity Our results on protein polymorphism suggest that cattle in China originated mainly from Bos indicus and Bos taurus; Xuwen, Hainan, Wenshan, and Dehong cattle and the Dehong zebu are close to zebu-type cattle, and Diqing and Zhaotong cattle are close to the taurine. The mithan was very different from other native cattle, and we suggest that its origin was complicated and may be influenced by other cattle species.

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.

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