The sire and dam each contribute 39 chromosomes to their offspring. Constitution - The manner in which an individual dog reacts to external or environmental influences. Dominant - The genetic information for a particular trait form one parent, e.g., eye color, that supersedes the genetic information from the other parent for the same trait. Familial - Traits which run in certain lines or groups of dogs. Gene - A basic unit of heredity.
Chromosomes contain many genes, and each gene is responsible for determining part of all of a trait.
Recent discoveries in genetic science have shown that there may be as many as 100,000 pairs of genes contributing to the construction of a dog, and 200,000 contributing to the construction of a human being. Genotype - Genes that are carried by a dog but not necessarily seen or expressed. Heredity - The traits a puppy acquires from its parents. These traits may be obvious or they may be hidden, yet passed on to subsequent generations. Hybrid - A dog with different genes for the same trait.