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Chu Q.,Beijing Academy of Agriculture and Forestry Sciences | Li D.,China Agricultural University | Hou S.,Anshan Hengli Dairy Cattle Farm | Shi W.,Beijing Dairy Cattle Center | And 2 more authors.
Yi chuan = Hereditas / Zhongguo yi chuan xue hui bian ji | Year: 2014

In this study, 139 bovine single nuclear polymorphisms (SNPs) were firstly selected and then directly sequenced using DNA pooling. Based on the ratio of two signal peak values, 92 SNPs with the ratio over 1/2 were considered as potential highly informative markers. To further verify the reliability of screening system, 59 SNP markers were genotyped in 122 Holstein cattle using matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) method. The results showed that 56 SNPs had a call rate higher than 85%. The minor allele frequency (MAF) of these 56 markers ranged from 0.27 to 0.5, with an average of 0.41; and in which 54 markers had a MAF over 0.3, covering 96.4% of this group of markers (54/56). Our findings indicate that direct sequencing of DNA pooling is a useful and efficient tool for identifying highly informative SNPs.

Alim M.A.,China Agricultural University | Fan Y.P.,China Agricultural University | Wu X.P.,China Agricultural University | Xie Y.,China Agricultural University | And 6 more authors.
Molecular Biology Reports | Year: 2012

Stearoyl-CoA desaturase (SCD) is a multifunctional complex enzyme important in the cellular biosynthesis of fatty acids. The present study was to investigate the association of the SCD gene with milk production traits in dairy cattle. Two single nucleotide polymorphisms (SNPs) (g.6926A>G and g.8646A>G) in introns 3 and 4, and three SNPs (g.10153A>G, g.10213T>C and g.10329C>T) in exon 5 were identified with pooled DNA sequencing and genotyped using matrix-assisted laser desorption/ionization time of flight mass spectrometry assay in 752 Chinese Holstein cows. Polymorphism g.10329C>T was predicted to result in an amino acid replacement from alanine to valine in the SCD protein. With a mixed animal model, the significant associations of the five SNPs with 305-day milk, fat and protein yields and protein percentage were determined. We further demonstrated cows with heterozygous genotypes (A/G or C/T) had highest 305 day milk yield, fat yield, protein yield and lowest protein percentage. Heterozygous cows with genotype AG at the g.6926A>G locus showed the greatest milk yield (P < 0.0001), fat yield (P < 0.0001) and protein yield (P < 0.0001) among other heterozygous genotypes at any of the loci. Dominance effects of all identified SNPs on milk, fat and protein yields and protein percentage were significant. Moreover, significant allele substitution effects at g.6926A>G locus on milk yield and at g.10213T>C on protein yield were observed. Five-locus haplotypes and strong linkage disequilibrium (D′ > 0.9) between the five SNPs were also observed. The results suggest that identified polymorphisms could be potential genetic markers to improve the production performance of Chinese Holstein. © 2012 Springer Science+Business Media B.V.

Chu M.X.,Chinese Academy of Agricultural Sciences | Ye S.C.,Chinese Academy of Agricultural Sciences | Qiao L.,Beijing Dairy Cattle Center | Wang J.X.,Chinese Academy of Agricultural Sciences | And 6 more authors.
Molecular Biology Reports | Year: 2012

Abstract In the present study, the exon 2 and 30 end sequence of intron 1 of BoLA-DRB3 gene of 211 Beijing Holstein cows was amplified and a uniform fragment of 284 bp was obtained. The genetic polymorphism was investigated by PCR-RFLP using two restriction endonucleases HaeIII and BstYI. Seven genotypes were detected by digesting the PCR products with HaeIII. The frequency of AA, AB, AC, AD, BB, BC and BF genotypes was 0.4638, 0.0193, 0.0193, 0.3478, 0.0290, 0.0386 and 0.0822, respectively. Three genotypes were found by digesting the PCR products with BstYI. The frequency of AA, AB and BB genotypes was 0.0569, 0.2844 and 0.6587, respectively. The relationship between the polymorphisms in exon 2 of BoLADRB3 gene and somatic cell score (SCS) in Beijing Holstein cows was analyzed by least squares linear model. No significant difference was detected among least squares means of SCS for seven HaeIII-RFLP genotypes (P>0.05). As for BstYI-RFLP analysis, least squares mean of SCS for AA was significantly lower than that for AB (P<0.05) or BB (P<0.05), and no significant difference was detected between AB and BB genotypes (P>0.05). BstYI AA was the most favorable genotype and BstYI BB was the most unfavorable genotype for mastitis resistance. The information found in the present study is very important for improving mastitis resistance in dairy cattle bymarker assisted selection.© Springer Science+Business Media B.V. 2011.

Alim M.A.,China Agricultural University | Xie Y.,China Agricultural University | Fan Y.,China Agricultural University | Wu X.,China Agricultural University | And 5 more authors.
Animal Production Science | Year: 2012

Milk and milk products are major components of human dietary intake and have a potential influence on health. In our experiment, associations between insulin-like growth factor 1 (IGF-I) gene polymorphism and milk-production traits were analysed in Chinese Holstein cattle. A polymorphism, transition at position g.1407 T > C, was identified in the 5′-flanking region of the IGF-I gene by pooled DNA sequencing. The identified single-nucleotide polymorphism (SNP) was genotyped by matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF MS) methods from 752 individuals. Significant associations between IGF-I genotypes and 305-day milk yield, fat yield and protein yield were found. Homozygous cows with TT genotype showed the highest milk, fat and protein yields, with increases of 532.75 kg, 23.57 kg and 14.69 kg, respectively, as compared with homozygous CC cows. Heterozygous CT cows had intermediate yields. Allele substitution showed that the C allele decreased milk yield (255.23 kg), fat yield (11.37 kg) and protein yield (7.05 kg), whereas it increased protein percentage (0.01%). The results suggest that IGF-I is a candidate gene that influences milk-production traits, and provides useful information to be implemented in breeding programs to improve the performance of the Chinese Holstein. © 2012 CSIRO.

Fan Y.,China Agricultural University | Wang P.,China Agricultural University | Fu W.,China Agricultural University | Dong T.,China Agricultural University | And 9 more authors.
Animal Genetics | Year: 2014

With the Illumina BovineSNP50K BeadChip, we performed a genome-wide association study (GWAS) for two pigmentation traits in a Chinese Holstein population: proportion of black (PB) and teat colour (TC). A case-control design was used. Cases were the cows with PB <0.30 (n = 129) and TC <2 points (n = 140); controls were those with PB >0.90 (n = 58) and TC >4 points (n = 281). The RM test of ROADTRIPS (version 1.2) was applied to detect SNPs for the two traits with 42 883 and 42 741 SNPs respectively. A total of nine and 12 genome-wide significant (P < 0.05) SNPs associated with PB and TC respectively were identified. Of these, two SNPs for PB were located within the KIT and IGFBP7 genes, and the other four SNPs were 23-212 kb away from the PDGFRA gene on BTA6; nine SNPs associated with TC were located within or 21-78.8 kb away from known genes on chromosomes 4, 11, 22, 23 and 24. By combing through our GWAS results and the biological functions of the genes, we suggest that the KIT, IGFBP7, PDGFRA, MITF, ING3 and WNT16 genes are promising candidates for PB and TC in Holstein cattle, providing a basis for further investigation on the genetic mechanism of pigmentation formation. © 2014 Stichting International Foundation for Animal Genetics.

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