The Theory of Path Coefficient Applied to Quantitative Genetic Analysis | Animal Husbandry & Veterinary Science Optional for UPSC PDF Download

The Theory of Path Coefficient Applied to Quantitative Genetic Analysis

Overview of Path Coefficient Method

• The path coefficient method is a traditional approach used to analyze genetic relationships among individuals. It focuses on tracing causal chains between initial causes and final effects. Correlation coefficients are used to quantify the strength of relationships between these events.

Application in Genetic Analysis

• This method helps measure correlations between zygotes, gametes, and their contributions in pedigrees. It simplifies relationships for straightforward cases but can become complex in pedigrees with numerous ancestors.

Estimation of Body Weight

• The method can be applied to estimate an animal's body weight based on causal relationships and path coefficients. For instance, an animal's final weight after a certain period can be calculated by summing its initial weight and weight gain.

Path Coefficient Calculation

• Path coefficients assign numerical values to different causal paths to quantify direct influences in a system of variables. These coefficients help determine how much a specific cause contributes to the variation of an effect.

Path Coefficient Definition

• The path coefficient from cause A to effect X is a standardized measure of the direct influence of A on X while keeping other causes constant. It is a dimensionless value similar to a correlation coefficient, indicating the direction of influence.

Comparison with Regression Coefficient

• Path coefficients resemble regression coefficients but are unitless and show the direction of influence from cause to effect. They are equivalent to standardized regression coefficients for standardized variables.