Paul Andersen explains how changes in the genotype of an individual can affect the phenotype. He begins with genotype:phenotype::letters:story analogy. He explains how mutations can be neutral, beneficial or harmful. He also explains how mistakes in the cell cycle can lead to disorder, sterility or new species.
Paul Andersen explains simple Mendelian genetics. He begins with a brief introduction of Gregor Mendel and his laws of segregation and independent assortment. He then presents a number of simple genetics problems along with their answers. He also explains how advances in genetic knowledge may lead to ethical and privacy concerns.