Back
Home
2.4 outline the use of highly variable genes for DNA fingerprinting of forensic samples, for paternity testing and for determining the pedigree of animals
define what is meant by polygenic inheritance and describe one example of polygenic inheritance in humans or another organism
- Wherever graduations in phenotype occur for a characteristic (rather than one or two definite phenotypes), the characteristic is polygenic and is controlled by more than one pair of genes.
- One example is height in humans – there are a large number of phenotypes, each differing slightly from the next and forming a graduated series. Some variation in height in humans is due to environmental factors such as diet, exercise and disease. However, if the environmental factors were constant, there would still be continuous variation in height due to such things as bone formation and hormone levels. The more genes that control a characteristic, the more possible gene combinations exist and the more phenotypes.
- Other examples of polygenic inheritance include: skin colour in humans, colour in wheat kernels, egg weight in poultry, fleece weight in sheep.