Hi folks, When you study Mendelian laws you learn about dominant alleles of a gene, A, or recessive alleles of a gene. My question is, What is its relation to DNA? -So in terms of bases we have A, T, C and G. And I know a gene may be in a chromosome and it may contain several million of these bases. What do we mean in terms of bases that a gene is recessive or dominant? Does that mean there are only two versions of that gene? I mean two different sequences of bases, one is the dominant and the other is the recessive. I am confused too with homozygous and heterozygous. In terms of bases what is an homozygous gene? DNA is a double stranded molecule of complementary bases, I don't see what could be a heterozygous gene. Thanks!