Traits and Genetics

For centuries, we knew that the characteristics were passed from parents to future generations. The way to determine the function is not always understood. One explanation that has been fascinating scientists for centuries is that the characteristics of parents are mixed, or mixed in later generations. The hybrid hypothesis explains many observable features and has been widely accepted for many years. However, the idea of ​​mixing can not explain the unexpected characteristics of a descendant. Until scientists discover the basis of cellular life to better understand trait inheritance.

First clarifying some terms will help you start. Evolution is simply to "change generations" (Brandon, 1990, p. 5). Changes occur due to natural selection, accidentalities, genetic drift, or because its characteristics are genetically related to other traits. If it is produced by a natural selection, the feature is adaptive. This feature is the result of natural selection and health is meant reproductive success only if "its popularity is due to the fact that it gives greater flexibility" (Richardson, 1996, p. 545)

Many of the interesting characteristics for animal production are quantitative features. Evaluation of the genetic value of animals is still largely based on the application of quantitative genetics theory. Traditionally, genetic improvement of livestock breeds was based on phenotypic selection. The past century has been characterized by the development of quantitative theories and methods to accurately select and predict genetic responses (Walsh, 2000). This led to the selection of many economically important genetic traits in cattle, sheep, pigs and poultry. The conceptual basis of this theory is a multigene model that assumes that quantitative traits are generated by the action (and interaction) of multiple secondary genes, each of which has minimal impact. Most morphological markers are gender limited, dependent on age, and are significantly affected by the environment. Biochemical markers show low polymorphism

The inheritance function is characterized by descendants inheriting from parents. These features exist in the form of genetic material DNA. Genetic material is carried by genetic carrier - chromosome. Each heterosexual gamete associated with sexual reproduction is donated in the form of genetic material. These features are represented in descendants and continue to be produced. This characteristic of moving from one generation to another is called a genetic characteristic.