GENETICS-BLOODTYPES

Humans can have one of four different ABO blood types: A, B, AB, or O. Blood tyes are determined by two co-dominant allels and one recessive allele.I guess the next question would be what is an allele? An allele is a form of genetic information that is in a certain part of our DNA on a specific chromosome.
There can be three different alleles for blood types: A, B, and O. The different blood types are caused by a protein cell surface marker. We all have two ABO blood type alleles, we get one from our biological mother and another one from our biological father. The description of the pair of alleles is called genotype. There can be six different genotypes but only four phenotypes.