Some of the most common diseases are infections caused by bacteria, such as Campylobacter, Salmonella, Shigella, E. coli O157:H7, Listeria, botulism, and norovirus.
A genotype is the actual genetic coding for an organism. A phenotype is the physical appearance. For example, let's say BB or Bb is the coding for black hair. BB/Bb is the genotype, and the black hair is the phenotype.
What is phenotype? Your genotype is your complete heritable genetic identity; it is 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.