What is genotype? What is phenotype?
Your genotype is your complete heritable genetic identity; it is essentially your unique genome that would be revealed by personal genome sequencing. However, the word genotype can also refer just to a particular gene or set of genes carried by an individual, rather than the entire genome of that individual. For example, if you carry a mutation that is linked to diabetes or heart disease, you may refer to your genotype just with respect to this mutation without consideration of all the other gene variants that your may carry.
In contrast, your phenotype is your actual physical characteristics. This includes straightforward characteristics like your height and eye color, but also your overall health, your disease history, and even your behavior and general disposition. Do you gain weight easily? Are you grumpy in the morning? Do you like cats? These are all ways in which you present yourself to the world, and as such are considered phenotypes. However, not all phenotypes are a direct result of your genotype; chances are that your personal disposition to cats is the result of your life’s experience with pets rather than a mutation in a hypothetical cat fancier gene. Most phenotypes are influenced by both your genotype and by the unique circumstances in which you have lived your life, including everything that has ever happened to you. We often refer to these two inputs as “nature”, the unique genome you carry, and “nurture”, the environment in which you have lived your life.