Gregor Mendel discovered the laws of inheritance by experimenting with pea plants and using Punnett squares to show the possible combinations of genetic traits being passed from parents to offspring. A monohybrid cross examines a single trait, while codominance occurs when multiple alleles for a gene are both expressed. The human genome project worked to catalogue all the DNA bases in humans to determine the sequence of A, T, C, and G and find genes associated with certain traits or molecules. DNA profiling uses genetic analysis to match unknown DNA samples to known ones for uses like identifying criminals or determining paternity.