β-agonist Regulate Skeletal Actin Gene Expression Post-transcriptionally

Previously reported studies have provided evidence that ractopamine regulates the expression of skeletal α- actin, but the molecular mechanisms underlying these effects are poorly understood. This was the first study to look specifically at the effects of ractopamine on the transcriptional regulation of a contractile protein in myotube cultures. Our model was sufficient to evaluate the anabolic effects of ractopamine in porcine skeletal muscle. However, we were unable to identify a cis-acting DNA element within the cloned porcine skeletal α-actin promoter that conferred transcriptional responsiveness to ractopamine in porcine skeletal muscle. Thus, it appears that ractopamine promotes the accumulation of skeletal α- actin mRNA in porcine skeletal muscle via a posttranscriptional mechanism. Elucidation of the mechanism whereby ractopamine increase skeletal muscle growth will aid in the development of new strategies, both genetic and pharmacological, to improve lean tissue deposition in livestock species

Genetic Nomenclature

Genetics includes the study of genotypes, phenotypes and the mechanisms of genetic control between them. Genetic terms describe the processes, genes, alleles and traits with which genetic phenomena are described and examined. In this chapter we will concentrate on the discussions of genetic term standardizations and, at the end of the chapter, we will list some terms relevant to genetic processes and concepts in a Genetic Glossary

Heritability of Genetic Resistance to Bovine Respiratory Diseases

Bovine Respiratory Disease (BRD) is the costliest disease facing the cattle industry. Therefore, the objective of this study was to better understand the genetic component of underlying resistance to bovine respiratory diseases. The focus of this study was to better understand the genetic differences between cattle that were more susceptible and/or more resistant to BRD. Data from Iowa State University’s cattle at the McNay Research Farm have been used to try to determine the best phenotypic measurement with which to identify resistant cattle to ultimately help producers in the selection of this economically relevant trait

Heritability of Genetic Resistance to Bovine Respiratory Disease

The objective of this study is to better understand the genetic component to bovine respiratory disease (BRD). The focus of this study is to research the genetic link between cattle that are more susceptible and cattle that are more resistance to BRD. Data from Iowa State University’s cattle at the McNay Research Farm and the Beef Teaching Farm, along with Iowa cattle producers, will be used to try to determine the best phenotypic measurement of resistance in cattle to ultimately help producers in selection of this economically relevant trait

Generation of Bovine Genetic Markers by Representational Difference Analysis: a genome subtraction technique

Representational Difference Analysis (RDA) is a genomic subtraction method to identify differences between two genomes. RDA was performed to isolate polymorphic cattle genetic markers that are potentially associated with carcass traits of interest. Sequence homology analysis indicated that some of the difference products had homology with known genes from cattle, human or mice, while most had no significant match. Over 20 different sequence tagged sites (STS), were generated. To evaluate the polymorphic nature of these RDA markers, genomic samples from five different cattle breeds were PCR amplified and sequenced. Polymorphisms in the form of single nucleotide polymorphisms (SNP) and base pair insertion were identified. Further, RDA generated STS markers were mapped to various bovine chromosomes. Thus, Genomic Representational Difference Analysis is suitable for generation of DNA markers and will help to increase the resolution of the bovine genomic map. In the future, we will evaluate the extent to which these marker may be used to predict phenotype. If successful, these marker may aid in the selection of breeding stock thereby improving the carcass composition of the end production of beef cattle production, high quality lean meat production

Identifying a Role for Tbx2 in Heart Development

Functional domains were identified within the Tbx2 protein. We have identified a couple of proteins that interact with Tbx2. Knowledge of how Tbx2 interacts with other proteins is essential in understanding how it inhibits gene expression during heart development

Identification of a Role for the Tyrosine Kinase JAK2 in Both Skeletal Muscle Mitogenesis and Myogenesis

This study was conducted to investigate what roles JAK2 might play in skeletal myoblast proliferation and terminal differentiation.These results represent the first characterization of the requirement of JAK2 in skeletal muscle proliferation, and suggest a novel role, potentially independent of kinase activity, for JAK2 in skeletal muscle myogenesis

Incidence of Infectious Bovine Keratoconjunctivitis

During 2003 an unusual number of calves showed signs of Infectious Bovine Keratoconjunctivitis (IBK), with 39.6% of the herd infected at the Rhodes Farm. Infectious Bovine Keratoconjunctivitis (IBK), commonly known as pink eye, is a contagious disease caused mostly by the bacteria Moraxella bovis, although other agents have been identified as a cause of IBK. Previous studies have shown that factors such as increased sunlight exposure, dust, tall grasses, and high populations of face flies (Musca autumnalis) facilitate M. bovis infection. Some of the symptoms associated with pink eye are reddening of the eyeball, swelling of the eyelid lining, followed by watery discharges. The study of this bacterial infection is important due to its effects on cattle performance, specifically weight gain. This preliminary analysis of data collected in the summer and fall of 2003 reveals the severity, persistence, and incidence of the disease. The analysis of the data also suggests a heritability (h2 = .180), which is similar to the narrow sense heritability obtained at the USDA Meat Animal Research Center, Clay Center, NE, taking into consideration the small size of our data

Myostatin Genotype Regulates Muscle-Specific miRNA Expression in Mouse Pectoralis Muscle

Loss of functional Myostatin results in a dramatic increase in skeletal muscle mass. It is unknown what role miRNAs play in Myostatin mediated repression of skeletal muscle mass. We hypothesized that Myostatin genotype would be associated with the differential expression of miRNAs in skeletal muscle. Loss of functional Myostatin resulted in a significant increase (p \u3c .001) in miR-1, miR-133a, miR-133b, and miR-206 expression. In contrast, Myostatin genotype had no effect (P \u3e .2) on miR-24 expression level. Myostatin genotype did not affect the expression level of MyoD or Myogenin (P \u3e 0.5). Myostatin may regulates the expression of miRNAs such as miR-133a, miR-133b, miR-1, and miR-206 in skeletal muscle as it has been observed that the expression of those miRNAs are significantly higher in myostatin null mice compared to wild type and heterozygous mice. In contrast, expression of myogenic factors such as MyoD or Myogenin has not been affected by myostatin in the muscle tissue

Standard Genetic Nomenglature of the Pig, with Glossaries

Genetics includes the study of genotypes, phenotypes and the mechanisms of genetic control between them. Genetic terms describe the processes, genes and traits with which genetic phenomena are described and examined. The genetic process terminologies are thoroughly discussed in the previous chapters. Therefore, in this chapter, we will only list the terms for genetic processes and concepts in Appendix I (a general genetic glossary), and concentrate the discussion on pig gene and trait terminologies (Appendix 10; a glossary for pig diseases and defects is also included (Appendix III)