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Non Mendelian Genetics Patterns of inheritance that aren’t simply dominant or recessive

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Non Mendelian Genetics Patterns of inheritance that arent simply dominant or recessive I. Incomplete Dominance II. Co-dominance A.The phenotypes of both homozygotes are produced in the heterozygous individuals; both alleles are expressed equally. B. Examples 1. Short-horned cattle red and white coats are co- dominant whiteo oiat 2. Chickens feather color; black and white are co- dominant 3. Four oclock plants red and white petals are co- dominant Short-horned cattle Four oclock plants Black and white feathers III. Multiple Alleles A.Traits controlled by more than 2 alleles. B. Examples 1. ABO blood type in humans A and B are codominant, but dominant to O 2. Pigeons feather color; B A, B and b; B A produces ash red feathers, B produces wild-type (grey) feathers, and b produces chocolate colored feathers IV. Polygenic Inheritance A.Many traits are controlled by 2 or more genes. B. Examples: 1. Eye color 2. Hair color 3. Skin color 4. Height Eye Color Skin Color V. Traits Influenced by the Environment A.An individuals phenotype often depends on conditions in the environment. B. Such factors as temperature, amount of sunlight, soil conditions and nutrition can affect the phenotype of an organism. C. Examples: 1. Arctic fox brown in summer; white in winter 2. Hydrangea flower color acidity of the soil determines blue or reddish color 3. Siamese cats cooler body areas are darker 4. Height in humans - early nutrition (or lack of) affects the height of humans The End!