Autosomal co-dominant refers to a type of inheritance pattern where two different alleles for a gene are both expressed equally in the phenotype of an organism. This means that neither allele is dominant over the other, allowing traits from both alleles to be visible. A common example of this is seen in the blood type system, where individuals with the genotype IAIB express both A and B antigens on their red blood cells. In autosomal co-dominance, the alleles are located on non-sex chromosomes, known as autosomes. This pattern can lead to a variety of phenotypes in offspring, depending on the combination of alleles inherited from each parent. Understanding this concept is important in fields like genetics and medicine, as it helps explain certain traits and conditions that can be passed down through families.