Genetics cat

The hereditary characteristics of a cat are, just like with all living organisms, determined by the genes. A cat has 19 pairs of chromosomes; each chromosome has been created out of a DNA (Double Deoxyribonucleic Acid) strip, which consists of thousands of pieces, called genes. The sex depends on the X- and Y-chromosomes. Female cats are XX and tomcats are XY. A female cat only passes X, the tomcat determines the kitten’s sex. Chromosomes include all hereditary characteristics like build, fur length, fur drawing, character etc and also the color. All cats have a gene for red. Red is only found on X and is therefore gender-linked. The X chromosome with the gene for red is indicated with XO, O is for dominant red. The cat is therefore noticeable red or has red spots (tortoise). The X chromosome without the gene for red is Xo, o stands for recessive red. The cat has any other color now (all other colors are a variation of black, for example blue and chocolate). A tomcat only has one X and is therefore XOY (red) or XoY (black). A female cat can be XoXo(black); XOXo or XoXO(tortoise) or XOXO(red). Red female cats therefore always have a red father; red tomcats always have a red or tortoise mother.  All cats have a gene in their chromosomes for hard or diluted colors. For hard colors this is the gene D and for diluted colors d. The gene for hard or real colors D is dominant with respect to the gene for diluted colors d. If a cat is homozygous for hard colors DD (black, chocolate or brown, cinnamon, red or tortoise) you will get a cat with hard colors. If the cat is heterozygous Dd (so a gene with diluted and a gene with hard colors) you will get a cat which has a noticeable hard color, but may inherit a diluted color. If a cat homozygous has the diluted gene dd, you will get a cat with noticeable diluted colors (blue, lilac, fawn, cream or blue cream). The hair color is produced by skin cells which actually feed the pigment in the hairs. The inhibitor gene, gene I, stops the pigment at the beginning of the hairs. This brings a variety of subtle patterns, which changes if the cat moves. With a uniform cat you will get smoke then, with a white under fur. With striped cats it is silver and a bit harder to observe, these cats often have a light or white under fur. The gene I can occur many times on the fur, a cat with a lot of gene I gets a very light fur with a small colored top. (shaded). The gene I doesn’t only regulate the hair colors. It also regulates the temperature sensitive extremities, these are called points. Point cats have a light body color and dark “points”; these include their ears, feet, tail and nose. Point cats have a warmth sensitive enzyme in their pigment cells in their skin, which causes their pattern. At a normal body temperature the fur is the lightest, at cold points the enzyme is activated and you will get a darker color. Since it is temperature sensitive these kittens are born white. Cats from cold surroundings get darker than cats from warm surroundings, all point cats also get darker as they grow older. All cats also wear a certain pattern, also the uniform colored cats. Geneticists call it the dominant agoeti gene A. Uniform colored cats have a genetic recessive gene for agoeti, non agoeti gene a. A uniform colored cat therefore is homozygous aa. A heterozygous cat AA has a tabby pattern and all kittens will also have this. The tabby genes have different patterns, some are dominant, and some are recessive. Ticked is the most dominant pattern. Striped is dominant over marbled, spotted and uniform, but not over ticked. Spotted is dominant over marbled and uniform, marbled is only dominant over uniform. A white marking off is dominant over fully colored. A cat with white can have the gene SS or Ss, if it has Ss the cat can inherit without white, SS can only produce kittens with white. A cat with the gene ss doesn’t have a white marking off. White hair doesn’t have a color producing pigment. Complete white cats have a dominant gene W. The white cat has a color (which can be found with the (grand) parents or by means of breeding), but you cannot see it. Deafness is often associated with the genes W and S, although it occurs more with white cats with blue eyes than with white cats with green, odd-eyed and yellow eyes. White cats aren’t albino cats; albino cats don’t have color in their eyes.