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ABSTRACT: The technological properties of milk have significant importance for the dairy industry. Citrate, a normal constituent of milk, forms one of the main buffer systems that regulate the equilibrium between Ca(2+) and H(+) ions. Higher-than-normal citrate content is associated with poor coagulation properties of milk. To identify the genes responsible for the variation of citrate content in milk in dairy cattle, the metabolic steps involved in citrate and fatty acid synthesis pathways in ruminant mammary tissue using RNA sequencing were studied. Genetic markers that could influence milk citrate content in Holstein cows were used in a marker-trait association study to establish the relationship between 74 single nucleotide polymorphisms (SNP) in 20 candidate genes and citrate content in 250 Holstein cows. This analysis revealed 6 SNP in key metabolic pathway genes [isocitrate dehydrogenase 1 (NADP+), soluble (IDH1); pyruvate dehydrogenase (lipoamide) β (PDHB); pyruvate kinase (PKM2); and solute carrier family 25 (mitochondrial carrier; citrate transporter), member 1 (SLC25A1)] significantly associated with increased milk citrate content. The amount of the phenotypic variation explained by the 6 SNP ranged from 10.1 to 13.7%. Also, genotype-combination analysis revealed the highest phenotypic variation was explained combining IDH1_23211, PDHB_5562, and SLC25A1_4446 genotypes. This specific genotype combination explained 21.3% of the phenotypic variation. The largest citrate associated effect was in the 3' untranslated region of the SLC25A1 gene, which is responsible for the transport of citrate across the mitochondrial inner membrane. This study provides an approach using RNA sequencing, metabolic pathway analysis, and association studies to identify genetic variation in functional target genes determining complex trait phenotypes.
Journal of Dairy Science 02/2013; · 2.56 Impact Factor
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M R S Fortes,
W M Snelling,
A Reverter,
S H Nagaraj,
S A Lehnert,
R J Hawken,
K L Deatley,
S O Peters,
G A Silver,
G Rincon, J F Medrano,
A Islas-Trejo,
M G Thomas
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ABSTRACT: Measures of heifer fertility are economically relevant traits for beef production systems and knowledge of candidate genes could be incorporated into future genomic selection strategies. Ten traits related to growth and fertility were measured in 890 Brangus heifers (3/8 Brahman × 5/8 Angus, from 67 sires). These traits were: BW and hip height adjusted to 205 and 365 d of age, postweaning ADG, yearling assessment of carcass traits (i.e., back fat thickness, intramuscular fat, and LM area), as well as heifer pregnancy and first service conception (FSC). These fertility traits were collected from controlled breeding seasons initiated with estrous synchronization and AI targeting heifers to calve by 24 mo of age. The BovineSNP50 BeadChip was used to ascertain 53,692 SNP genotypes for ∼802 heifers. Associations of genotypes and phenotypes were performed and SNP effects were estimated for each trait. Minimally associated SNP (P < 0.05) and their effects across the 10 traits formed the basis for an association weight matrix and its derived gene network related to FSC (57.3% success and heritability = 0.06 ± 0.05). These analyses yielded 1,555 important SNP, which inferred genes linked by 113,873 correlations within a network. Specifically, 1,386 SNP were nodes and the 5,132 strongest correlations (|r| ≥ 0.90) were edges. The network was filtered with genes queried from a transcriptome resource created from deep sequencing of RNA (i.e., RNA-Seq) from the hypothalamus of a prepubertal and a postpubertal Brangus heifer. The remaining hypothalamic-influenced network contained 978 genes connected by 2,560 edges or predicted gene interactions. This hypothalamic gene network was enriched with genes involved in axon guidance, which is a pathway known to influence pulsatile release of LHRH. There were 5 transcription factors with 21 or more connections: ZMAT3, STAT6, RFX4, PLAGL1, and NR6A1 for FSC. The SNP that identified these genes were intragenic and were on chromosomes 1, 5, 9, and 11. Chromosome 5 harbored both STAT6 and RFX4. The large number of interactions and genes observed with network analyses of multiple sources of genomic data (i.e., GWAS and RNA-Seq) support the concept of FSC being a polygenic trait.
Journal of Animal Science 06/2012; 90(9):2894-906. · 2.10 Impact Factor
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ABSTRACT: The aim of this study was to evaluate the effect of genetic variants on candidate genes corresponding to the sterol recognition element-binding protein-1 (SREBP-1) signaling pathway and stearoyl-CoA desaturases (SCD1 and SCD5) on muscle fatty acid (FA) composition of Brangus steers fattened on grass. FA profiles were measured on Longissimus lumborum muscle samples using a gas chromatography-flame ionization detection technique. A total of 43 tag single-nucleotide polymorphisms on the SCD1, SCD5, SREBP-1, SCAP, INSIG1, INSIG2, MBTPS1, MBTPS2, and SRPR genes were genotyped on 246 steers to perform a marker-trait association study. To evaluate the influence of the Indicine breed in the composite breed, additional groups of 48 Angus, 18 Hereford, 75 Hereford x Angus, and 36 Limousin x Hereford-Angus steers were also genotyped. To perform the association analysis, FA data were grouped according to the number of carbon atoms and/or number of double bonds (i.e. SFA, MUFA, PUFA, etc.). In addition, different indexes that reflect the activity of FA desaturase and elongase enzymes were calculated. SCD1 markers significantly affected C14:1/(C14:0 + C14:1) and C18:1/(C18:0 + C18:1) indexes, whereas one SNP in SCD5 was correlated with the C16:1/(C16:0 + C16:1) index. Polymorphisms in the signal recognition particle receptor (SRPR) gene were associated with all the estimated desaturase indexes. Because the evaluated markers showed no effect on total lipid content of beef, this work supports the potential utilization of these markers for the improvement of grass-fed beef without undesirable side effects.
Animal Genetics 06/2012; · 2.40 Impact Factor
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ABSTRACT: Two high-density single nucleotide polymorphism (SNP) genotyping arrays have recently become available for bovine genomic analyses, the Illumina High-Density Bovine BeadChip Array (777,962 SNP) and the Affymetrix Axiom Genome-Wide BOS 1 Array (648,874 SNP). These products each have unique design and chemistry attributes, and the extent of marker overlap and their potential utility for quantitative trait loci fine mapping, detection of copy number variation, and multibreed genomic selection are of significant interest to the cattle community. This is the first study to compare the performance of these 2 arrays. Deoxyribonucleic acid samples from 16 dairy cattle (10 Holstein, 6 Jersey) were used for the comparison. An independent set of DNA samples taken from 46 Jersey cattle and 18 Holstein cattle were used to ascertain the amount of SNP variation accounted by the 16 experimental samples. Data were analyzed with SVS7 software (Golden Helix Inc., Bozeman, MT) to remove SNP having a call rate less than 90%, and linkage disequilibrium pruning was used to remove linked SNP (r² ≥ 0.9). Maximum, average, and median gaps were calculated for each analysis based on genomic position of SNP on the bovine UMD3.1 genome assembly. All samples were successfully genotyped (≥ 98% SNP genotyped) with both platforms. The average number of genotyped SNP in the Illumina platform was 775,681 and 637,249 for the Affymetrix platform. Based on genomic position, a total of 107,896 SNP were shared between the 2 platforms; however, based on genotype concordance, only 96,031 SNP had complete concordance at these loci. Both Affymetrix BOS 1 and Illumina BovineHD genotyping platforms are well designed and provide high-quality genotypes and similar coverage of informative SNP. Despite fewer total SNP on BOS 1, 19% more SNP remained after linkage disequilibrium pruning, resulting in a smaller gap size (5.2 vs. 6.9 kb) in Holstein and Jersey samples relative to BovineHD. However, only 224,115 Illumina and 241,038 Affymetrix SNP remained following removal of SNP with a minor allele frequency of zero in Holstein and Jersey samples, resulting in an average gap size of 11,887 bp and 11,018 bp, respectively. Combining the 354,348 informative (r² ≥ 0.9), polymorphic (minor allele frequency ≥ 0), unique SNP data from both platforms decreased the average gap size to 7,560 bp. Genome-wide copy number variant analyses were performed using intensity files from both platforms. The BovineHD platform provided an advantage to the copy number variant data compared with the BOS 1 because of the larger number of SNP, higher intensity signals, and lower background effects. The combined use of both platforms significantly improved coverage over either platform alone and decreased the gap size between SNP, providing a valuable tool for fine mapping quantitative trait loci and multibreed animal evaluation.
Journal of Dairy Science 12/2011; 94(12):6116-21. · 2.56 Impact Factor
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ABSTRACT: Reproductive disorders in dairy herds have a negative effect on farm profitability and sustainability of milk production. Given the substantial evidence of the role of the pregnancy-associated plasma protein (PAPP) gene family in the regulation of reproduction in humans and mice, its role in insulin-like growth factor metabolism, quantitative trait loci effects in the mouse, and location of a calving ease QTL on bovine chromosome 16, the PAPP-A2 gene was chosen as a candidate gene to perform an association study for reproductive health in cattle. Single nucleotide polymorphisms (SNP) were identified in coding and conserved noncoding regions of the PAPP-A2 gene in 3 dairy breeds. A total of 7 tag SNP were genotyped in 662 Holstein bulls (UCD-bulls) to perform marker trait association analysis. Three SNP (SNP 13, 15, and 16) were in strong linkage disequilibrium in Holsteins, showing significant positive associations with daughter calving ease, productive life, milk yield, and protein yield. These results were validated by genotyping SNP15 in a larger population of 992 bulls from the cooperative dairy DNA repository (CDDR-bulls). Our results demonstrate that the PAPP-A2 gene is associated with reproductive health in Holstein cattle and that the identified SNP can be used as genetic markers in dairy breeding due to their positive association with reproductive and productive traits. Functional studies need to be conducted to identify the mechanisms for the association of SNP with these traits.
Journal of Dairy Science 03/2011; 94(3):1552-8. · 2.56 Impact Factor
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ABSTRACT: ETH10 is a dinucleotide microsatellite within the promoter of signal transducer and activator of transcription 6 (STAT6) gene on bovine chromosome 5. ETH10 is included in the panel of genetic markers used in parentage testing procedures of cattle breed associations. Allelic sizes of ETH10 PCR amplicons range from 199 to 225 bp. Objectives of this study were to use microsatellite data from beef cattle breed associations to investigate genetic distance and population stratification among Angus- and Brahman-influenced cattle and to use ETH10 genotypes and growth and ultrasound carcass data to investigate their statistical relationships. Three series of genotype to phenotype association analyses were conducted with 1) Angus data (n=5,094), 2) Brangus data (3/8 Brahman × 5/8 Angus; n=2,296), and 3) multibreed data (n=4,426) of Angus and Brangus cattle. Thirteen alleles and 38 genotypes were observed, but frequencies varied among breed groups. Tests of genetic identity and distance among 6 breed composition groups increasing in Brahman influence from 0 to 75% revealed that as Brahman-influence increased to ≥50%, genetic distance from Angus ranged from 18.3 to 43.5%. This was accomplished with 10 microsatellite loci. A mixed effects model involving genotype as a fixed effect and sire as a random source of variation suggested that Angus cattle with the 217/219 genotype tended to have 2.1% heavier (P=0.07) 205-d BW than other genotypes. In Brangus cattle, allele combinations were classified as small (≤215 bp) or large (≥217 bp). Brangus cattle with the small/large genotype had 2.0% heavier (P<0.05) birth weight, yet cattle with the large/large genotype had approximately 5.1% greater (P<0.05) percentage of fat within LM and more LM per BW than cattle with small/large or small/small genotypes. Genotype-to-phenotype relationships were not detected in multibreed analyses. The ETH10 locus appears to be associated with growth and carcass traits in Angus and Brangus cattle. Results from this study provide support for STAT6 as one of the candidate genes underlying cattle growth QTL on chromosome 5.
Journal of Animal Science 02/2011; 89(7):2031-41. · 2.10 Impact Factor
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M C Baeza,
P M Corva,
L A Soria,
G Rincon, J F Medrano,
E Pavan,
E L Villarreal,
A Schor,
L Melucci,
C Mezzadra,
M C Miquel
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ABSTRACT: The somatotropic axis is a major regulatory pathway of energy metabolism during postnatal growth in mammals. Genes involved in this pathway influence many economically important traits. The association of selected SNPs in these genes with carcass traits was examined in grazing Brangus steers. These traits included final live weight, ultrasound backfat thickness (UBFT), rib-eye area, kidney fat weight, hot carcass weight, and intramuscular fat percentage (%IMF). Genomic DNA (N = 246) was genotyped for a panel of 15 tag SNPs located in the growth hormone receptor (GHR), insulin-like growth factor I, insulin-like growth factor-binding protein 6, pro-melanin-concentrating hormone, suppressor of cytokine signaling 2, and signal transducer and activator of transcription 6 (STAT6) genes. Allelic and haplotype frequencies were compared with those of a sample of European breeds (N = 177 steers). Two tag SNPs in the GHR affected %IMF; one of them (ss86273136) was also strongly associated with UBFT (P < 0.003). The frequency of the most favorable GHR haplotype for %IMF was lower in Brangus steers. Moreover, the haplotype carrying two unfavorable alleles was present at a frequency of 31% in this group. Four tag SNPs on STAT6 had a significant effect on UBFT. One of these, SNP ss115492467, was also associated with %IMF. The STAT6 haplotype, including all the alleles favoring UBFT, was the most abundant variant (34%) in the European cattle, while it had a frequency of 14% in the Brangus steers. The four less favorable variants (absent in the European cattle) were found at a frequency of 38% in the Brangus steers. These results support the association of GHR and STAT6 SNP with carcass traits in composite breeds, such as Brangus, under grazing conditions.
Genetics and molecular research: GMR 01/2011; 10(4):3146-56. · 1.18 Impact Factor
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P Luna-Nevarez,
G Rincon, J F Medrano,
D G Riley,
C C Chase,
S W Coleman,
D M Vanleeuwen,
K L DeAtley,
A Islas-Trejo,
G A Silver,
M G Thomas
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ABSTRACT: The growth endocrine axis influences reproduction. The objectives of this study were to evaluate population genetic characteristics of SNP genotypes within genes of the GH-IGF axis in straightbred and crossbred Angus, Brahman, and Romosinuano heifers (n = 650) and to test the association of these genotypes with measures of reproduction. These objectives were achieved using 73 SNP within 7 genes on chromosome 5 and the pregnancy-associated plasma protein A2 (PAPP-A2) and GH-receptor genes, which map to chromosomes 16 and 20, respectively. The SNP were elucidated by resequencing conserved regions of each gene by using DNA from familial-unrelated cattle of a multibreed discovery population. A multiplex SNP assay yielded 59 biallelic SNP useful for evaluating genetic identity and distance. Specifically, the divergence of straightbred Brahman cattle was approximately 15.5% from 5 Bos taurus-influenced breed groups. In the straightbred groups used as a validation population, only 3 SNP had minor allele frequencies >10%. These SNP were in the genes PAPP-A2 (ss115492449-A/C and ss115492450-G/T within intron 10) and signal transducers and activators of transcription 2 (STAT2; ss252841035-A/G within the 5' untranslated region), and they met the conditions of Hardy-Weinberg equilibrium (P > 0.31). The other 56 SNP were useful for assigning each animal into ancestral clusters (n = 3 proportions) to account for population stratification in genotype to phenotype association analyses. The 2 SNP in the PAPP-A2 gene influenced (P < 0.05) traits indicative of first-calf heifer rebreeding (i.e., calving interval, days to calving, and pregnancy rate). A STAT2 SNP genotype (i.e., GG) × primary ancestral cluster interaction (P < 0.05) suggested heifers primarily of B. taurus ancestry had a reduction of approximately 16.4 ± 0.1% in calving interval and days to calving relative to heifers clustering primarily as Bos indicus ancestry. Even though additional research is needed to delineate the allelic variation attributed to genes of the GH-IGF axis, results of this study provide support for STAT2 and PAPP-A2 as potential candidate genes associated with first-calf heifer rebreeding traits.
Journal of Animal Science 12/2010; 89(4):926-34. · 2.10 Impact Factor
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ABSTRACT: A dairy cattle breeding simulation program (DCBSP v.4.9) has been developed to teach undergraduate and graduate students animal breeding principles associated with selection for multiple traits in dairy cattle. The current version of the program was written in FORTRAN 90, and a web-based interface was developed for the students to interact with the program in the teaching environment. This software simulates a population of dairy cattle herds and artificial insemination bulls through several generations by integrating students' decisions about mating, culling, and selection of new heifers and bulls based on a multivariate animal mixed model evaluation and marker-assisted selection. All simulation parameters (e.g., number of herds and cows per herd, variance components, effect of genetic markers) can be defined by the administrator of the program in relation to the animal breeding course. During each running period, the program simulates the composition of each herd during a virtual year, generating new calves and new productive records and performing a genetic evaluation for all productive traits. A herd-specific productive summary of all demographic, productive, and genetic data is provided to the students at the end of each simulation period. After several running periods, the genetic trend can be evaluated, providing a realistic experience for the development of animal breeding skills that will be relevant to students with a basic knowledge of animal breeding. Earlier versions of this program have been used at several universities where it has proven to be a very useful teaching tool to illustrate the theoretical basis of animal breeding in livestock.
Journal of Dairy Science 06/2010; 93(6):2816-26. · 2.56 Impact Factor
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Journal of Animal Breeding and Genetics 04/2010; 106(1‐6):110 - 119. · 1.46 Impact Factor
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ABSTRACT: Identification of the genes and polymorphisms underlying quantitative traits, and understanding how these genes and polymorphisms affect economic traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle populations. Signal transducer and activator of transcription 6 (STAT6) gene is tightly connected to IL-4 and IL-13 signalling and plays a key role in T(H)2 polarization of the immune system. In addition, STAT6 acts as a mediator of leptin signalling and has been associated with body weight regulation. The objective of this study was to determine if SNPs within the bovine STAT6 gene are associated with economically important traits in feedlot cattle. The approach consisted of resequencing STAT6 using a panel of DNA from unrelated animals of different beef breeds. Specifically, 16 kb of STAT6 was resequenced in 47 animals and the process revealed 39 SNPs. From the 39 SNPs, a panel of 15 tag SNPs was genotyped in 1500 beef cattle samples with phenotypes to perform a marker-trait association analysis. Among the 15 tag SNPs, five and six were polymorphic in Bos taurus and Bos indicus respectively. An association analysis was performed between the 15 tag SNPs and 14 performance and production traits. SNP ss115492459:C > A, ss115492461:A > G and ss115492458:G > C were significantly associated with back fat, calculated yield grade, cutability, hot carcass weight, dry matter intake, days on feed, back fat rate and average daily gain. These three SNPs were present in all Bos taurus beef breeds examined. Our results provide evidence that polymorphisms in STAT6 are associated with carcass and growth efficiency traits, and may be used for marker-assisted selection and management in feedlot cattle.
Animal Genetics 06/2009; 40(6):878-82. · 2.40 Impact Factor
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ABSTRACT: To fine map a quantitative trait locus (QTL) affecting milk production traits previously associated with microsatellite RM188, we implemented an interval mapping analysis by using microsatellite markers in a large Israeli Holstein half-sib sire family, and linkage disequilibrium (LD) mapping in a large set of US Holstein bulls. Interval mapping located the target QTL to the near vicinity of RM188. For the LD mapping, we identified 42 single nucleotide polymorphisms (SNP) in 15 genes in a 12-Mb region on bovine chromosome 4. A total of 24 tag SNP were genotyped in 882 bulls belonging to the University of California Davis archival collection of Holstein bull DNA samples with predicted transmitted ability phenotypes. Marker-to-marker LD analysis revealed 2 LD blocks, with intrablock r(2) values of 0.10 and 0.46, respectively; outside the blocks, r(2) values ranged from 0.002 to 0.23. A standard additive/dominance model using the generalized linear model procedure of SAS and the regression module of HelixTree software were used to test marker-trait associations. Single nucleotide polymorphism 9 on ARL4A, SNP10 on XR_027435.1, SNP12 on ETV1, SNP21 on SNX13, and SNP24 were significantly associated with milk production traits. We propose the interval encompassing ARL4A and SNX13 genes as a candidate region in bovine chromosome 4 for a concordant QTL related to milk protein traits in dairy cattle. Functional studies are needed to confirm this result.
Journal of Dairy Science 03/2009; 92(2):758-64. · 2.56 Impact Factor
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ABSTRACT: Expression of the GH receptor (GHR) gene and its binding with GH is essential for growth and fat metabolism. A GT microsatellite exists in the promoter of bovine GHR segregating short (11 bp) and long (16 to 20 bp) allele sequences. To detect SNP and complete an association study of genotype to phenotype, we resequenced a 1,195-bp fragment of DNA including the GT microsatellite and exon 1A. Resequencing was completed in 48 familialy unrelated Holstein, Jersey, Brown Swiss, Simmental, Angus, Brahman, and Brangus cattle. Nine SNP were identified. Phylogeny analyses revealed minor distance (i.e., <5%) in DNA sequence among the 5 Bos taurus breeds; however, sequence from Brahman cattle averaged 27.4 +/- 0.07% divergence from the Bos taurus breeds, whereas divergence of Brangus was intermediate. An association study of genotype to phenotype was completed with data from growing Brangus bulls (n = 553 from 96 sires) and data from 4 of the SNP flanking the GT microsatellite. These SNP were found to be in Hardy-Weinberg equilibrium and in phase based on linkage disequilibrium analyses (r(2) = 0.84 and D'= 0.92). An A/G tag SNP was identified (ss86273136) and was located in exon 1A, which began 88 bp downstream from the GT microsatellite. Minor allele frequency of the tag SNP was greater than 10%, and Mendelian segregation was verified in 3 generation pedigrees. The A allele was derived from Brahman, and the G allele was derived from Angus. This tag SNP genotype was a significant effect in analyses of rib fat data collected with ultrasound when bulls were ~365 d of age. Specifically, bulls of the GG genotype had 6.1% more (P = 0.0204) rib fat than bulls of the AA and AG genotypes, respectively. Tag SNP (ss86273136), located in the promoter of GHR, appears to be associated with a measure of corporal fat in Bos taurus x Bos indicus composite cattle.
Journal of Animal Science 08/2008; 86(12):3315-23. · 2.10 Impact Factor
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Advances in experimental medicine and biology 02/2008; 606:345-56. · 1.09 Impact Factor
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ABSTRACT: A mass balance optimization model was developed to determine the value of the kappa-casein genotype and milk composition in Cheddar cheese and whey production. Inputs were milk, nonfat dry milk, cream, condensed skim milk, and starter and salt. The products produced were Cheddar cheese, fat-reduced whey, cream, whey cream, casein fines, demineralized whey, 34% dried whey protein, 80% dried whey protein, lactose powder, and cow feed. The costs and prices used were based on market data from March 2004 and affected the results. Inputs were separated into components consisting of whey protein, ash, casein, fat, water, and lactose and were then distributed to products through specific constraints and retention equations. A unique 2-step optimization procedure was developed to ensure that the final composition of fat-reduced whey was correct. The model was evaluated for milk compositions ranging from 1.62 to 3.59% casein, 0.41 to 1.14% whey protein, 1.89 to 5.97% fat, and 4.06 to 5.64% lactose. The kappa casein genotype was represented by different retentions of milk components in Cheddar cheese and ranged from 0.715 to 0.7411 kg of casein in cheese/kg of casein in milk and from 0.7795 to 0.9210 kg of fat in cheese/kg of fat in milk. Milk composition had a greater effect on Cheddar cheese production and profit than did genotype. Cheese production was significantly different and ranged from 9,846 kg with a high-casein milk composition to 6,834 kg with a high-fat milk composition per 100,000 kg of milk. Profit (per 100,000 kg of milk) was significantly different, ranging from $70,586 for a high-fat milk composition to $16,490 for a low-fat milk composition. However, cheese production was not significantly different, and profit was significant only for the lowest profit ($40,602) with the kappa-casein genotype. Results from this model analysis showed that the optimization model is useful for determining costs and prices for cheese plant inputs and products, and that it can be used to evaluate the economic value of milk components to optimize cheese plant profits.
Journal of Dairy Science 03/2007; 90(2):616-29. · 2.56 Impact Factor
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ABSTRACT: Suppressor of cytokine signaling 2 (SOCS2) is a negative regulator of growth hormone signaling. The deletion of SOCS2 in mice results in a 30-50% increase in post-natal growth. In an effort to identify polymorphisms in the SOCS2 gene that may be associated with body size in dogs, we characterized the canine SOCS2 gene and analyzed its genetic diversity among small and large dog breeds. The study was carried out on a total of 520 dogs from 66 different breeds. Dogs were classified as large or small based on height and weight as determined by their respective American Kennel Club breed standards. The SH2 and SOCS domains of the canine SOCS2 gene were sequenced in 32 dogs from different breeds. Only one non-synonymous sequence variant (DQ415457:g.326G>T) was detected which corresponds to an amino acid change (Asp127Tyr). All samples were genotyped by PCR/RFLP and the allele frequencies were determined for each dog breed. The T allele was distributed primarily among European large dog breeds with a gene frequency ranging from 0.72 to 0.04. The nature of the nucleotide change and the effect on the protein together with the finding of a QTL related to body size in the same CFA15 region by other researchers suggest canine SOCS2 as a potential candidate gene for body size in dogs. Future studies will be needed to clarify the role of the 326G>T polymorphism and its interaction with genes like growth hormone and insulin-like growth factor 1.
Genetics and molecular research: GMR 02/2007; 6(1):144-51. · 1.18 Impact Factor
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Animal Genetics 07/2006; 37(3):294-5. · 2.40 Impact Factor
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ABSTRACT: Polyunsaturated fatty acids (PUFA) are important components of mammalian diets, and the beneficial effects of n-3 PUFA on human development and cardiovascular health have been well documented. Caenorhabditis elegans is one of the few animals known to be able to produce linoleic (LA, 18:2n-6) and alpha-linolenic (ALA, 18:3n-3) essential fatty acids. These essential PUFA are generated by the action of desaturases that successively direct the conversion of monounsaturated fatty acids (MUFA) to PUFA. The cDNA coding sequences of the C. elegans Delta(12) and n-3 fatty acid desaturases were each placed under the control of separate constitutive eukaryotic promoters and simultaneously introduced into HC11 mouse mammary epithelial cells by adenoviral transduction. Phospholipids from transduced cells showed a significant decrease in the ratios of both MUFA:PUFA and n-6:n-3 fatty acids relative to control cultures. The fatty acid profile of transduced cellular phospholipids revealed significant decreases in MUFA and arachidonic acid (20:4n-6), and increases in LA, ALA, and eicosapentaenoic acid (20:5n-3). The fatty acid composition of triacylglycerols derived from transduced cells was similarly, but less dramatically, affected. These results demonstrate the functionality of C. elegans fatty acid desaturase enzymes in mammalian cells. Expression of these desaturases in livestock might act to counterbalance the saturating effect that rumen microbial biohydrogenation has on the fatty acid profile of ruminant products, and allow for the development of novel, land-based dietary sources of n-3 PUFA.
Journal of Dairy Science 04/2005; 88(3):1142-6. · 2.56 Impact Factor
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ABSTRACT: In this study the flanking sequences of 1534 horse microsatellites were used in a BLAST search to identify putative human-horse homologies. BLAST searches revealed 129 flanking sequences with significant blastn matches [alignment scores (S) > or = 60 and sum probability values (E) < or = 3.0E-6], also, 25 of these produced significant blastx matches. To provide a reference point in the human genome the flanking sequences with matches were subjected to a BLAT search of the University of California Santa Cruz (UCSC) human genome assembly (July 2003 freeze). Eighty-three of the flanking sequences showed high similarity to sequence of known or putative human genes and the remaining 46 demonstrated high similarity to human intragenic regions. Interestingly, 87 of the microsatellites showed conservation of the tandem repeat in addition to flanking regions. Overall, 41 of the microsatellites had been mapped in the horse and of these 37 localized to the expected syntenic location. The other four did not and represent new putative regions of human-horse synteny. The results of this study contribute 79 new putative human-horse homologies, increasing the density of markers on the human-horse comparative map.
Animal Genetics 02/2004; 35(1):28-33. · 2.40 Impact Factor
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ABSTRACT: An accurate, sensitive, and quick (approximately 3 h) method for determining the sex of ovine embryos was developed using polymerase chain reaction (PCR) primers derived from an ovine-specific Y-chromosome random amplified polymorphic DNA marker (UcdO43). The accuracy and sensitivity of the assay were first tested using genomic DNA from 10 males and 10 females of five different sheep breeds, and then tested using serial dilutions of male-in-female DNA. The assay was 100% accurate in confirming the sex of the individuals and the ovine male-specific fragment was detected in dilutions containing as little as 10 pg of male DNA in 50 ng of female DNA. The assay was also confirmed to be specific for the ovine Y-chromosome as bovine, caprine, porcine, murine, and human DNA did not amplify. The ovine embryo sexing method is a duplex PCR system that also includes ZFY/ZFX primers. ZFY/ZFX provide an internal positive control for amplification as well as a means to confirm the results obtained with the UcdO43 primers. All embryo sexing results (36/36) from our method were in agreement with the ZFY/ZFX assay results. However, while our method requires an internal control to detect PCR failure, it has the advantages of not requiring nested PCR or restriction endonuclease digestion of the PCR product, and concerns about cross-species contamination are eliminated.
Animal Genetics 12/2003; 28(2):135 - 138. · 2.40 Impact Factor
