By John Daniel “JD” Fogarty and Jude Kwaku Poku January 28 Period 3
Color Blindness is defined as the inability to distinguish between certain colors. Color Blindness occurs when there is an absence of color-sensitive pigments in the cone cells of the retina, or the nerve layer at the back of the eye. Color Blindness symptoms can vary. Some people may have trouble seeing red, while others may have a difficulty with blue. These kinds of deficiencies are not so serious. For a person who has a full on color deficiency, the only colors they can see are different shades of black, white, and grey.
WWhat numbers do you see?
CColor blindness is X-linked recessive in the mother’s chromosome. It is more common in males than females.
People acquire the genetic disorder of color deficiency through birth. A color defective male always inherits the deficiency though his mother who usually has normal color vision, but is a carry of the defect.
Punnett squares are used to show the probability of receiving a genetic disorder from a parent. GGGgGg GgGggg G g Gg Mom Dad
Ratios: 1: 2: 1 1 GG 2 Gg 1gg Percentages: 25%: 50% 25% 25% GG 50% Gg 25% gg GGGgGg GgGggg G g Gg
Uppercase letters represent dominant genes while lowercase represent recessive genes, which are always over powered by the dominant genes. A red gene represents a gene that is not a carrier of color blindness, while a green gene represents a gene that is a carrier. GGGgGg GgGggg G g Gg PHENOTYPES: WHAT YOU SEE GG=RED Gg=RED (Green Gene Carrier) gg= Green GENOTYPES: WHAT IS IN THE GENES GG= Homozygous dominant (RED) Gg= Heterozygous dominant (RED with Green) gg= Homozygous recessive (Green)
Phenotype: Ratio: 3 RED:1 Green Percentages: 75% RED:25% Green Genotype: Ratio: 1 GG:2 Gg:1 gg Percentages: 25% GG: 50% Gg: 25% gg GGGgGg GgGggg G g Gg
AA Aaaa AA A aTTT Tttt Tt T t XXXy xy Xy X x
Genotype: Ratio: 1XX:2Xy:1xy Percent: 25% XX:50%Xy:25%xy Phenotype: Ratio: 2 RED:2 Green Percent: 50% RED:50% GreenXXy XyXyxyxy X y X x Total Percentage for color blindness:50%