Calculating Inbreeding Coefficient_Syekat Fish World

Individual inbreeding values can be calculated by using a technique called pathway analysis. In path analysis you convert a pedigree to a path diagram and determine the inbreeding of an individual by adding the different possible paths to one or more common ancestor. For Example:

Each arrow of the path diagram represents a gamete and 50% of an individual genome. Individual inbreeding values are calculated by using the following formula:

Where,

F_x = The inbreeding of an individual

N= Number of individual in a given path

F_A =The inbreeding of the common ancestor

If  F_A  is 0 the equation will be as follows:

Individual G in the preceding pedigree is inbreed because one of his ancestors appears on both the maternal and paternal side of the pedigree (the definition of a common ancestor). Individual A is the common ancestor of G. The inbreeding of G is determined by tracing a path from G to A. When you trace the path, what you will do is determine how A's genes ended up in G. To do this, you start with one of G's parents, trace a path to A, and then trace the path from A to G's other parent: To calculate F_G,  trace a path from D to E, through G's common ancestor:

Common ancestor of G: A

There are 3 individuals in this path , so the value of N = 3

Individual A is not inbreed . So, Calculation of F_G  is :

If more than one common ancestor exists, you simply add the products of each path. For example ,