What is a Pedigree Chart A diagram that

What is a Pedigree Chart? A diagram that shows the occurrence of a genetic trait in several generations of a family. It traces the inheritance of a trait within a family.

Symbols used in Pedigree Charts

The pedigree above traces the inheritance of a vary rare biochemical disorder in humans. Affected individuals are indicated by filled-in circles and squares. • • Is the allele for this disorder dominant or recessive? dominant What genotypes are possible for the individuals marked 1, 2, and 3? 1. 2. 3. Heterozygous (hybrid) Homozygous Recessive

The pedigree above represents the inheritance of colon cancer within a family. Dark-shaded symbols represent individuals with one of the two major types of colon cancer. Numbers under the symbols are the individual's age at the time of diagnosis. What is the genotype of the deceased individual in generation II? A) homozygous for a gene for colon cancer B) homozygous for both cancer alleles from his mother C) heterozygous for a gene for colon cancer D) affected by the same colon cancer environmental factor as his mother E) carrier of all of the several known genes for colon cancer

What evidence suggests that this pedigree shows the inheritance of a sex-linked trait? • Affected are mostly males • Only females are carriers

This pedigree chart shows the inheritance of colorblindness, a sex-linked trait, in a family. 1. Explain, in terms of inheritance and genotype, why the female in the fourth generation is a carrier. She inherited the recessive gene for color-blindness from her dad and could pass it on to her son or daughter. She inherited a normal dominant gene for color vision from her mom, so she has normal vision. 2. The carrier female in the fourth generation marries a color-blind man. What are the possible genotypes and phenotypes of their offspring?

2. The carrier female in the fourth generation marries a color-blind man. What are the possible genotypes and phenotypes of their offspring? Use a key and a punnett square to support your answer. Key X = gene for color vision X- = gene for color-blindness Y = Y chromosome X- Y X X X- X Y X X Y 25% 25% Normal Male Color-blind Male Carrier Female Color-blind Female 1. What is the chance that they will have a daughter that is color-blind? 2. What is the chance that their daughter is color-blind? 3. What is the chance that their child will be

Key X = gene for color vision X- = gene for color-blindness Y = Y chromosome X Y X X X- X Y X- X- Y 25% 25% Normal Male Color-blind Male Carrier Female Color-blind Female 1. What is the chance that they will have a daughter that is color-blind? 25% 2. What is the chance that their daughter is color-blind? 50% 3. What is the chance that their child will be color-blind? 50%

Name ________ What are the possible blood types and genotypes of individuals 1, 7, and 10? O AB 3 1 2 A A O 4 5 6 A 10 9 B 7 A A 11 12 O AB A AB B 11 12 13 14 8 15

What are the possible blood types and genotypes of individuals 1, 7, and 10? AB 3 Ao O 1 2 A A O A B 4 5 6 7 8 Bo or AB A 10 9 A A 11 12 O AB A AB B 11 12 13 14 15