This document summarizes key concepts in genetics, including that genes determine traits, alleles are different forms of genes, dominant traits always show up when the dominant allele is present while recessive traits only show up without dominant alleles present, Mendel discovered traits are not blended but inherited separately, phenotypes are visible traits while genotypes are genetic makeup, genotypes can be homozygous with two identical alleles or heterozygous with two different alleles, and Punnett squares can predict offspring genotypes.