In sexual reproduction, genetic material from the sire and dam are passed on to their offspring in the form of DNA. The makeup of DNA consists of two strands of genetic material that connect to each other forming what is known as “base pairs”. How these base pairs align with each other, become the genetic blueprint for a particular trait. These aligned base pairs of DNA (one from each parent) are called GENES. Genes are located within chromosomes. A GENE LOCUS is where a gene is located on a chromosome. One published analogy likened a chromosome to a music CD; the genes found on the chromosome, occupy a specific location or “locus” much like music is found on a specific track. This is an important concept to keep in mind, when we talk about the different GENE SERIES OR LOCI later in this guide.