Quantitative Trait Loci (QTLs) mapping for growth traits in the mouse: A review

The attainment of a specific mature body size is one of the most fundamental differences among species of mammals. Moreover, body size seems to be the central factor underlying differences in traits such as growth rate, energy metabolism and body composition. An important proportion of this variability is of genetic origin. The goal of the genetic analysis of animal growth is to understand its "genetic architecture", that is the number and position of loci affecting the trait, the magnitude of their effects, allele frequencies and types of gene action. In this review, the different strategies developed to identify and characterize genes involved in the regulation of growth in the mouse are described, with emphasis on the methods developed to map loci contributing to the regulation of quantitative traits (QTLs)

Genome-wide isolation of growth and obesity QTL using mouse speed congenic strains

BACKGROUND: High growth (hg) modifier and background independent quantitative trait loci (QTL) affecting growth, adiposity and carcass composition were previously identified on mouse chromosomes (MMU) 1, 2, 5, 8, 9, 11 and 17. To confirm and further characterize each QTL, two panels of speed congenic strains were developed by introgressing CAST/EiJ (CAST) QTL alleles onto either mutant C57Bl/6J-hg/hg (HG) or wild type C57Bl/6J (B6) genetic backgrounds. RESULTS: The first speed congenic panel was developed by introgressing four overlapping donor regions spanning MMU2 in its entirety onto both HG and B6 backgrounds, for a total of eight strains. Phenotypic characterization of the MMU2 panel confirmed the segregation of multiple growth and obesity QTL and strongly suggested that a subset of these loci modify the effects of the hg deletion. The second panel consisted of individual donor regions on an HG background for each QTL on MMU1, 5, 8, 9, 11 and 17. Of the six developed strains, five were successfully characterized and displayed significant differences in growth and/or obesity as compared to controls. All five displayed phenotypes similar to those originally attributed to each QTL, however, novel phenotypes were unmasked in several of the strains including sex-specific effects. CONCLUSION: The speed congenic strains developed herein constitute an invaluable genomic resource and provide the foundation to identify the specific nature of genetic variation influencing growth and obesity

Genetic and environmental factors influencing beef tenderness

Tenderness is one of the most important quality attributes of beef. However, it is difficult to predict and its causation is complex. Tenderness is influenced by factors inherent to the animal, such as its genetic constitution, management and feeding, and also by practices employed at slaughter and subsequent handling of the meat. In spite of the large number of factors involved, research results indicate that tenderness can be increased through genetic improvement of animals. In this review the structure of skeletal muscle and its relation to subsequent tenderness of the meat are described. Also discussed are the principal genetic and environmental factors that determine its variability. Emphasis is placed on the role of molecular marker technology in prediction of meat tenderness and in animal improvement

Diferenciales de selección genética en Holando Argentino

La selección genética en ganado lechero a nivel global ha resultado en aumentos considerables en la productividad. En contraste, la producción de leche en Argentina se ha mantenido estable durante los últimos 20 años, aún cuando otros países con sistemas productivos similares han incrementado significativamente su producción en el mismo periodo. El objetivo de este estudio fue determinar los diferenciales de selección realizados en la población de Holando Argentino bajo el modelo de selección de 4 víasEEA BalcarceFil: Pardo, Alan M. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Corva, Pablo. Unidad Integrada Balcarce. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Dillon Anabella Unidad Integrada Balcarce. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Rubio, Natalia. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina.Fil: Andere, C. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina.Fil: Casanova, D. Universidad Nacional del Centro de la Provincia de Buenos Aires, Facultad de Ciencias Veterinarias; Argentina

Hematologyand Serum Biochemistryof Free-Ranging Nutria (Myocastor Coypus)

Information on reference blood values in the literature is lacking for many wild rodents. In this study, comprehensive reference intervals (RIs) for a wide range of analytes from 101 healthy free-ranging nutria were determined. Animals were captured in Buenos Aires, Argentina (378509S, 578349W), and southward (388609S, 588239W), encompassing major biotopes of agricultural pampas with dunes and grassland steppes on the east coast. Traps were set at locations with high-density nutria populations (i.e., those areas that showed signs of movement, territorial marking, or feeding activities). Although the small sample size limits the interpretation of these findings, RIs were determined by a robust method using the central 95th percentile. In nutria, the RI range varied greatly for the leukocyte differentials, with mature neutrophils: 3,907–5,544/ll for females and 3,744–5,900/ll for males; band neutrophils: 0–10/ll for females and 3–18/ll for males; lymphocytes: 4,213– 5,940/ll for both sexes combined; monocytes: 165–402/ll for both sexes combined; eosinophils: 13–91/ll for females and 108–165/ll for males; and basophils: 0–87/ll for both sexes combined. Platelet concentration was 543–727 3 109/L for both sexes combined. There was also a wide RI range for biochemistry values for some enzymes, such as alkaline phosphatase: 200–399 IU/L for both sexes combined; cholinesterase: 762–1,407 IU/L for females and 763–1,284 IU/L for males; creatine kinase: 182–552 IU/L for females and 162–451 IU/L for males; amylase: 853–1,865 IU/L for females and 779–1,293 IU/L for males; and glucose concentration 120.2– 180.6 mg/dl for both sexes combined. Conversely, there was not a wide pooled RI range for calcium: 7.0–11.2 mg/dl; phosphorous: 6.1–9.3 mg/dl; sodium: 133.0–159.0 mEq/L; potassium: 3.0–8.2 mEq/L; chloride: 101.4– 143.0 mEq/L; and urea: 11.3–36.8 mg/dl. The red blood cell indices had a narrow range, with mean corpuscular volume: 84.0 102.5 fl and mean corpuscular hemoglobin concentration: 18.2–28.8 g/dl, and which was most likely due to strict physiologic controls. The results from this study were similar to those previously reported for farmed nutria

The association of CAPN1 316 marker genotypes with growth and meat quality traits of steers finished on pasture

The objective of this paper was to determine the association of a SNP in the μ-calpain gene at position 316 with growth and quality of meat traits of steers grown on pasture. Fifty-nine Brangus and 20 Angus steers were genotyped for CAPN1 316. Warner Bratzler shear force was measured in l. lumborum samples after a 7-day aging period. A multivariate analysis of variance was performed, including shear force (WBSF), final weight (FW), average daily gain (ADG), backfat thickness (BFT), average monthly fat thickness gain (AMFTG), rib-eye area (REA), and beef rib-eye depth (RED) as dependent variables. The CAPN1 316 genotype was statistically significant. Univariate analyses were done with these variables. The marker genotype was statistically significant (p < 0.05) for WBSF (kg: CC: 4.41 ± 0.57; CG: 5.58 ± 0.20; GG: 6.29 ± 0.18), FW (kg: CC: 360.23 ± 14.71; CG: 381.34 ± 5.26; GG: 399.23 ± 4.68), and ADG (kg/d: CC: 0.675 ± 0.046; CG: 0.705 ± 0.016; GG: 0.765 ± 0.014) Shear force, final weight and average daily gain were significantly different according to the CAPN1 316 marker genotypes. The marker genotype was statistically significant in the multivariate analysis (p = 0.001). The first characteristic root explained 89% of the differences among genotypes. WBSF, FW and ADG were the most important traits in the first vector, indicating that animals with the marker genotype for lowest WBSF also have the lowest FW and ADG

Quantitative Trait Loci (QTLs) mapping for growth traits in the mouse: A review

The attainment of a specific mature body size is one of the most fundamental differences among species of mammals. Moreover, body size seems to be the central factor underlying differences in traits such as growth rate, energy metabolism and body composition. An important proportion of this variability is of genetic origin. The goal of the genetic analysis of animal growth is to understand its "genetic architecture", that is the number and position of loci affecting the trait, the magnitude of their effects, allele frequencies and types of gene action. In this review, the different strategies developed to identify and characterize genes involved in the regulation of growth in the mouse are described, with emphasis on the methods developed to map loci contributing to the regulation of quantitative traits (QTLs)