Differentiate between genes and alleles. 2. can a person's genotype be determine by their phenotype

Gene is a sequence of nucleotides on the DNA that determines a certain trait. When the gene mutates, it takes up two or more forms. These forms are called the alleles. Example, in the pea plant, a gene codes for the color of the pea. This gene exists in two forms, one gives yellow color to the peas and the other gives green color to the peas. The two forms can be present together in the genome. Their expression will determine the dominance of one form over the other (in this case yellow color is dominant over the green color).

A person's genotype can be guessed but not accurately estimated by looking at the phenotype. A phenotype can be a result of the action of two or more genes expressing together. Though a pedigree analysis on the inheritance of certain kinds of genes can reveal the mode of inheritance, i.e., if its autosomal gene inheritance or sexually-linked gene inheritance.