Get a slate, marker and

eraser

What type of diagram shows a trait being passed from one

generation to the next?

A Pedigree

What symbol is used to indicate male on a pedigree?

What symbol is used to indicate female on a pedigree?

Show a mated male and female

Show a sister and brother

Show parents with two children (one boy and one girl).

Show the same family, but the son has a trait that neither parent

has.

Is the trait dominant or recessive?

Recessive

Use the letter A for the trait. Indicate the genotype (or possible

genotypes) or each person.

AA or Aa aa

Aa Aa

Show parents with three children. (Two boys and one girl)

Show the same family. Mom and the daughter have a trait.

Is the trait dominant or recessive?

It is impossible

to tell

This is a dominant trait. Indicate the genotype (or possible

genotypes) of each person.

Aa

Aa

aa

aa aa

This is a recessive trait. Indicate the genotype (or possible

genotypes) of each person.

aa

aa

Aa

Aa Aa

A family has a boy who cannot roll his tongue and a girl who can. Their father is able to roll his tongue, but

the mother is not. Mom’s father cannot roll his tongue, but all of the other grandparents can. Draw the

pedigree for this family.

White – Can Roll Tongue

Determine the genotype (or possible genotypes) of each person.

rr Rr

White – Can Roll Tongue

Rr rr

rr RrRR or Rr RR or Rr

At least one of these must be Rr

A litter of mice has three males and three females. One male is white, but all of the others are black. The parents and grandparents are all

black. Mom’s maternal grandfather is white. All other great-

grandparents are black. Draw the pedigree and write the genotypes

that you can determine.

bb

Bb Bb

Bb

bb

A dark mouse (a dominant trait) has a grandparent who is white.

What is his genotype?

DD or Dd

A dark mouse (a dominant trait) has a grandparent who is white.

What is his genotype?

How could you determine his genotype?

Cross him with a white mouse.

THIS IS CALLED A TEST CROSS