Lesson 18 Using Punnett Squares and Pedigrees Bb x Bb male / sperm female / eggs X BB BbBbbb BbBb B b Bb Remember this?

A Punnett Square is a diagram used to identify _____________ combinations resulting from a mating. This married couple is considering having their first baby. The man is heterozygous for a disease. The woman is also heterozygous for the disease.

The couple comes to you for counseling. They want you to tell them are the chances they will have a healthy baby.

You know that the disease they carry is a recessive trait and that both parents are heterozygous. RRRrrr Which of the above genotypes will you need to use? Man x Woman __ ?

Man x Woman ____ __ Genotype % RR = Rr = rr = ___% Phenotype % Healthy = Carrier = Diseased = ___% The chance that the couple will have a baby that has the disease is _____%.

Who you are…

___________ = family record for one specific trait. __________________ traits = genes for these traits are carried on the sex chromosomes. __________________ traits = genes for these traits are carried on the sex chromosomes. The gene for Red- Green _______ _______________ is carried on the ___ chromosome. Female must get ___(___) X’s to have colorblindness. Male must get ___(__Y) X to have colorblindness. Why are most sex-linked traits carried on the X chromosome?

Analyzing a Pedigree Interactive Reading a Pedigree = male carrier= female carrier = male without trait = male with trait = female without trait = female with trait = two parents = three children