Genetics Study Guide

Monohybrid inheritance describes the inheritance of a single characteristic, determined by a single gene. Each gene has different forms called alleles, which can be dominant or recessive. A dominant allele expresses its characteristic even when only one copy is present, while a recessive allele only expresses its characteristic when two copies are present. An individual's genetic makeup for a trait is called its genotype, and the observable characteristic is its phenotype. Genetic diagrams, Punnett squares, and family pedigrees are tools used to predict and illustrate the patterns of monohybrid inheritance. Genetic diagrams show the genotypes of parents and predict the genotypes and phenotypes of offspring. Punnett squares provide a visual representation of all possible combinations of alleles from two parents, allowing for the calculation of probabilities for offspring genotypes and phenotypes. Family pedigrees track the inheritance of a trait through multiple generations within a family, using standard symbols to represent individuals, their sex, and whether they express the trait.

The Human Genome Project (HGP) was an international scientific research project with the primary goal of determining the sequence of chemical base pairs that make up human deoxyribonucleic acid (DNA), and of identifying and mapping all of the genes of the human genome from both a physical and functional standpoint. Completed in 2003, it provided an essentially complete map of the human genetic blueprint. The outcomes of the HGP have profoundly impacted biological research and medicine, leading to a much deeper understanding of human biology and disease. Its applications in medicine are vast, including advancements in diagnostics, personalized medicine, gene therapy, and drug development. By identifying genes associated with various diseases, the HGP has paved the way for more targeted and effective treatments, as well as improved predictive testing for genetic conditions. This knowledge also underpins pharmacogenomics, allowing for drug prescriptions tailored to an individual's genetic makeup, thereby optimising efficacy and reducing adverse effects.