Rate of genetic change - ABG Exam 2

Four categories that affect change

accuracy of selection

selection intensity

genetic variation

generational interval

accuracy of selection

the accuracy of our prediction of the parent’s true BVs

effected by heritability

selection intensity

how “Choosy” we are being with the parents we select

Genetic Variation

The variability pf BV for a trait under selection

the range available for selection

Genetic interval

which animal would we expect to see genetic change occur faster

the amount of time required to replace one generation with the next

The Key equation

Rate of change = accuracy x intensity x variation / generational interval

key equation written

BV/T = Rbvbv x i x sigmabv / L

i = selection criterion

sigma = SD

L = time

rBVBV

the correlation between true BV’s and their predictions for a trait under selection

Between 0 and 1

i

the difference between the mean selection criterion for all the individuals selected to be parents (SCs) and the meaning standard criterion for all individuals (SC) divided by the standard deviation

How to select for threshold traits

choose a trait after the truncation point, ut may not be best performers

Linear

The rate of genetic change isn’t linear because the values used in the key equation can change if there are new practices, new technologies, or just new BV developed over time

Practical key equation

rate of change = heritability x intensity x variation / interval

why is it more important to select males than females?

Males have higher selection accuracy

males can be more intensely selected