This document discusses several concepts in genetics beyond Mendel's laws of inheritance: 1) Incomplete dominance results in an intermediate phenotype in heterozygotes, such as pink flowers from a cross of red and white flowering plants. 2) Co-dominance occurs when two alleles are fully expressed in the phenotype, like the ABO blood groups in humans where the IA and IB alleles both produce antigens. 3) Pleiotropy is when one gene affects multiple phenotypic traits, such as genes for dwarfism or gigantism affecting both height and other body features. 4) Epistasis occurs when one gene masks the expression of another gene, as in coat color genes in mice or dogs.