In order to tell the difference between the two you must first know what the difference is between the genome and the genotype. Only then can you understand the difference between genotype and phenotype.
The genome is a collection of DNA and is actually nothing more than a list of all the genes within the body of an organism. From the functioning of the kidneys to the color of the eyes and the shape of the nose.
The genotype is defined as “the set of genes of an animal”. It would be exactly the same as the genome but the difference lies in the fact that the genotype is all the genetic material within an animal which focuses on one part of the body. That may be about, for example, the color of the skin and eyes or the construction of an animal’s skeleton or a specific organ function. The genotype is used to indicate the difference between what is determined by the genes and what we see on the outside.
The phenotype is the genotype plus the environmental factors. Despite the fact that genotype determines the properties of organs or the appearance of an animal, it can change considerably by environmental factors. The best example is the research on a group of rabbits. One half lived on a beautiful green land and the other half lived on a barren piece of land with little edible grass but full of other sources of food. Both groups are doing well and reproduce. But after a number of generations they changed significantly in their looks. The rabbits on the green land got a bright color and smooth coat. Their intestines have become accustomed to the fresh grass. The rabbits on the barren land got darker and their fur turned coarser. They eat less fresh grass but a lot of dry grass or hay. But their genetic characteristics remain the same and are transmitted in the same way to their children.
Use in breeding
The genotype and phenotype in animals, is mainly used for the colors within a species. The genetic code of a color is then called the genotype and the colors that we can see if humans are the phenotype.