Give an example of genetic codominance and explain what is meant by this phrase.

This question can be divided into two aspects; example and explanation. Firstly, the example - there are several examples of genetic codominance, including the presence of the AB blood group, variation in animal colours (think roan horses or cows) and sickle cell anaemia. Secondly, the explanation - genetic codominance is when two alleles that denote a particular characteristic are expressed equally, rather than either being dominant or recessive. This can be demonstrated through the presence of an AB blood group, because both A and B proteins are produced, rather than one over the other. The same is true of sickle cell anaemia, with some blood cells being sickle shaped and others being normally shaped.