The purpose of this report is to inform dog breeders of a very common genetic disease known as Progressive retinal atrophy (PRA). The report will also inform buyers of the disease so they are aware of the disorder and they can check to dog’s pedigree for the disease. PRA could affect any dog, as a result of this it is recommended that the offspring should be examined by a board-certified veterinary ophthalmologist and screened for the existence of the disorder. 2. Recessive and dominant genes
Genes are genetic instructions that define what we look like, a phenotype, and how our cells are made up, a genotype. “Genes are made up of DNA and are organized into larger structures called chromosomes, which are located within the nucleus of the cell.” (Lofts, G. 2012)
(Image 1: The link between DNA, Genes, Chromosomes, Nucleus and Cells) Genes play an extremely important part in how we look. Genes carry information about our cells that create a persons characteristic. (eg. Eye Colour, Hair Colour, Skin colour etc.) Genes can also be described as instruction manuals. Genes are made up of DNA, which carries the instructions to make and operate parts of our bodies. (learn.genetics.utah.edu, 2004) Genes are passed from parent to offspring through a type of cell division called meiosis. Meiosis is used in the production of sex cells. (Gametes) The Female gamete is the ova and the male gamete is the sperm. “This process results in the chromosome number being halved, so instead of pairs of chromosomes in each resulting cell, there is only one chromosome from each pair.” (Lofts, G. 2012) This genetic information was then put into 23 chromosomes from each your mother and your father. This results in 46 chromosomes, which makes up a zygote. The difference between a dominant and a recessive gene is that a dominant gene is a gene overrides the recessive gene. It can suppress the recessive gene therefore it changes the allele even though...