What does Dominant with Incomplete Penetrance Mean?
All chromosomes exist in pairs in the nucleus of cells. Each pair is comprised of one chromosome from the sire and one from the dam. Therefore, every animal has two copies of every gene. In dogs there are 78 chromosomes, or 39 pairs. The traits that we see in an individual are collectively known as the “phenotype”, while the “genotype” refers to genetic constitution or makeup of an individual. A mutation is a permanent change in the DNA sequence of a gene, whether it be good, bad or neutral . Mutations that cause a genetic disease can be inherited as dominant where one bad copy of the gene is sufficient to cause disease or a phenotypic trait to be observed, or recessive where two bad or mutated copies of the gene are needed to cause disease or phenotypic trait to be observed. Dominant with incomplete penetrance refers to a situation where an inherited mutation may or may not be expressed in an individual Penetrance refers to the frequency that the phenotype (or some characteristics of
