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The insulin-like growth factor-1 (IGF-1), a key hormone in muscle development was investigated for single-nucleotide polymorphisms (SNPs) upstream of the IGF-1 gene and their effects upon its cognate mRNA and hormone levels in sheep. A 70 d feeding trial was conducted with 22 F1 (Dorper × Pelibuey) lambs, individually allocated and fed a diet with a forage-to-concentrate ratio of 36:64 and 17% crude protein. Sequence analyses of 265 bp upstream the IGF-1 gene revealed the variant NC_040254.1:g.[184028491G > C;184028493G > A]. These SNPs generate alleles A and B, with frequencies of 0.66 and 0.34 in F1 lambs and of 0.73 and 0.27 in 81 pure Dorper lambs, respectively. Females were grouped by genotype AA, AB and BB (n = 3). IGF-1 hormone concentrations at 14, 42 and 70 d were higher (p < 0.05) in AA lambs compared to AB + BB lambs. The IGF-1 mRNA level was 2.6-fold higher in AA animals (n = 5, p < 0.05) than in AB + BB lambs (n = 7). A DNA binding site for the Inhibitor of Growth family member 4 (ING4) was found in allele B but not in allele A, which could explain the lower mRNA and hormone expression levels for AB + BB animals. The variant reported here appears to function as an eQTL with a negative effect on the level of IGF-1. [ABSTRACT FROM AUTHOR]

Reports in the literature suggest that a transient surge of ghrelin secretion (TSGS) just before a scheduled meal may be triggered by an appetite mechanism. Also, it is known that circulating ghrelin concentrations fluctuate relative to nutritional status and influence feeding behavior. The aim of the present study was to search for genetic variants in five selected genes (GHRL, GHSR1a, MBOAT4, NPY and AgRP) within the ghrelin gene (GHRL) interaction network. gDNA was extracted from the six highest- and six lowest-RFI Hampshire non-castrated male lambs, out of a total of 25 lambs in a 56-d GrowSafe SystemsÒ feeding trial and the complete genes were amplified by PCR. Libraries were prepared and sequenced in the ILLUMINA platform MiniSeq Sequencing System. Variations were identified using the genomic variant call format (GVCF) workflow with HaplotypeCaller using the reference genome oviAri 4 - Oar_v4 (GCA_000298732.2). One hundred and ninety-two SNPs were found in the five analyzed genes. Most of them had been reported in the SNPs data base. Linear models including each SNP genotype at a time as fixed effects, in addition to ADG and mid test metabolic body weight as covariates for some variables, were adjusted. Forty-three of these SNPs had different genotype frequencies in the two RFI groups, and appear to be associated (p < 0.05) with traits such as RFI, feed intake (FI), feed conversion (FC) and ghrelin hormone concentration in plasma (GHRL) at the TSGS; especially SNPs rs399405301, rs421869734, rs604106535, rs417836509, rs600356564, rs590893697 at the MBOAT4 gene which resulted highly significant (p < 0.01) for RFI and GHRL. The SNP rs423156356 at the GHSR1a gene was highly significant (p < 0.01) for FI and FC. These SNPs (Table 1) have the potential to be used as genetic markers for improvement of feed efficiency in Hampshire sheep, but validation on a larger sample deserves further research efforts. [ABSTRACT FROM AUTHOR]

The objective of this study was to identify in Angus and Brangus breed animals with extreme temperament, measured as exit velocity, genomic regions and candidate genes associated with bovine temperament. The population was genotyped with the Genomic Profiler HD 150K chip and after the genome-wide association analysis, the SNPs rs 133956611 (F=2.65 E-06) and rs81144933 (P=9.58 E-06) were associated with temperament. The mapping analysis of the regions close to the SNP rs81144933 identified the SNCA (alpha-synuclein) zxAMMRNl (multimerin-1) genes at 222.8 and 435.9 Kb downstream respectively, while for the rsl33956611 loci the gene GPRIN3 (GPRIN family-member-3) was identified at 245.7 Kb upstream, all three genes are located on the BTA6 chromosome. The analysis of SNCA protein-protein interactions allowed the identification of the genes APP (β-amyloid precursor protein), PARK7 (parkinsonism-associated-deglycase), UCHL1 (ubiquitin-C-terminal-hydrolase-Ll), PARK2 (parkin-RBR-E3-ubiquitin-protein-ligase), and genes of the SLC family as candidates to be associated with bovine temperament. All these candidate genes and their interacting were resequenced, which allowed the discovery of new SNPs in the SNCA and APP genes. Of these, the SNPs located in introns 5, 8 and 11 of the APP gene affect splicing site motifs. These results indicate that SNCA and its interacting genes are candidates to be related to bovine temperament. [ABSTRACT FROM AUTHOR]

In order to define the SNP panel for paternity tests in cattle, genotypes were analyzed in three breeds (number of SNPs evaluated and individuals sampled): Hereford (HER; 202; 1317), Brangus (BRA; 217; 3431) and Limousin (LIM; 151; 8205). Within breed, SNPs with a percentage of genotyped individuals (PGI) less than 90 %, with Hardy-Weinberg disequilibrium (HW; 7*0.05), with allele frequency less than 0.10 or less and with linkage disequilibrium, where the correlation between genotypic frequencies was greater than 0.25, were discarded. The levels of expected (He) and observed (Ho) heterozygosity, polymorphic information content (PIC) were estimated; as well as the Shannon index, the fixation index and effective population size (Ne). The combined exclusion probability (CEP) and identity probability (CIP) were calculated. The final panel was 121, 188 and 113 SNPs in HER, BRA and LIM, respectively; the main source of discard was HW followed by PGI. Levels of Ho and He were above 0.40; CIP was greater than 0.32 and Ne presented estimates above 181.3. The results for CEP were higher than 0.999999; for CIP, they were below 1 × 10-20. [ABSTRACT FROM AUTHOR]