Days to 230 lb. The concept of heritability can also be examined from the standpoint of selection response. This concept is diagrammed in Figure 2. A diagrammatic relationship of the performance of parents and the expected performance of their progeny relative to the population mean for traits with differing heritabilities. The cause of the likeness between parent and offspring is because genes are passed from the parent to the offspring.
Sibs tend to be alike because they share genes in common which are received from their parents.
There is a greater likeness between relatives for a highly heritable trait than for a lowly heritable trait. For example, a group of sibs is more likely to be similar for backfat thickness than for number born in their first litter. Genes, as compared to management, have a greater effect on performance for a highly heritable than for a lowly heritable trait. Differences among animals can have both genetic and environmental causes. The heritability of a trait is the ratio of variation due to genetic causes to the variation due to genetic plus plus environmental causes.