Genotype = two letters
The father's and mother's gene segment that defines a characteristic is called a genotype. It is usually represented by two letters.
It’s easiest to remember what a genotype is when you think of it as meaning two letters.
The jeans can type (genotype) two letters at once.
Each possible genotype can be shown using a punnet square.
In this example the mother has brown eyes but carries one brown eye allele and one blue eye allele. The father is also brown eyed but again carries one blue eye allele and one brown eye allele.