Bell Ringer Blood Punnett Squares What are the

Bell Ringer: Blood Punnett Squares: What are the Genotypes for the Blood Phenotypes? A: B: AB: O: 1. Cross AB Blood with Heterozygous B Blood. What are the results/possibilities? 2. Cross Homozygous A Blood with Heterozygous B Blood. What are the results/possibilities? 3. Cross O Blood with Heterozygous A Blood. Is there a possibility of O Blood?

Pedigrees

Pedigree Chart that shows the relationships between a family.

Roman Numerals Represent the Family Generations Pedigrees A circle represents a female. I A horizontal line connecting a male and female represents a marriage. II A half-shaded circle or square indicates that a person is a carrier of the trait. III A completely shaded circle or square indicates that a person expresses the trait. A square represents a male. A vertical line and a bracket connect the parents to their children. A circle or square that is not shaded indicates that a person neither expresses the trait nor is a carrier of the trait.

Sample Pedigree • 1. This pedigree shows the inheritance of attached ear lobes. Which parent has attached ear lobes? • 2. How many children do the parents have? Which child has attached ear lobes? • 3. Which child is married? Does this child’s spouse have attached ear lobes? Do any of this child’s children have attached ear lobes? n = Attached Earlobes N = Free Earlobes I II III

Hemophilia: “The Royal Disease”

Sex-linked Traits copyright cmassengale 8

Sex-linked Traits • Traits (genes) located on the sex chromosomes • Sex chromosomes are X and Y • XX genotype for females • XY genotype for males • Many sex-linked traits carried on X chromosome copyright cmassengale 9

Sex-linked Traits Example: Eye color in fruit flies Sex Chromosomes fruit fly eye color XX chromosome - female Xy chromosome - male copyright cmassengale 10

Sex-linked Trait Problem • Example: Eye color in fruit flies • (red-eyed male) x (white-eyed female) XRY x X r • Remember: the Y chromosome in males does not carry traits. • RR = red eyed Xr Xr • Rr = red eyed • rr = white eyed • XY = male XR • XX = female Y copyright cmassengale 11

Sex-linked Trait Solution: Xr XR XR Xr Y Xr XR Xr Xr Y 50% red eyed female 50% white eyed male copyright cmassengale 12

Female Carriers copyright cmassengale 13