Ogre+Traits

Use pages 32 and 33 in your science notebook. (Not Cornell)
 * 1) 18 Punnett Practice (Ogre Traits)

Remember: Capital letters are used for dominant traits and lower case are used for recessive traits. A genotype consist of two letters representing the two alleles of the organism. A phenotype is the trait the organism shows. Purebreds are homozygous, so their alleles are the same. (Both letters are the same.) Hybrids are heterozygous, so their alleles are different. (The two letters are different.) How to fill out a Punnett square is on textbook page 164.

Investigating the probability of traits in ogre offspring.

A. Green teeth are dominant and white teeth are recessive. Use a Punnett square to show a cross between a purebred dominant and a purebred recessive. Use the letter “G”.

1. Give the probable genotypes of the offspring: a) Homozygous dominant genotype is .......... b) Percent homozygous dominant present?

c) Heterozygous genotype is ........................ d) Percent heterozygous present?

e) Homozygous recessive genotype is........... f) Percent homozygous recessive present?

2. Give the ratio of the genotypes of the offspring.

3. Give the ratio of the phenotypes of the offspring.

4. What percent will have the dominant phenotype?

5. What percent will have the recessive phenotype?

B. Hairy pits are dominant and hair-free pits are recessive. Use a Punnett square to show a cross between a hybrid and another hybrid. Use the letter “H”. 1. Genotypes: a) Homozygous dominant genotype is ........... b) Percent homozygous dominant?

c) Heterozygous genotype is ......................... d) Percent heterozygous?

e) Homozygous recessive genotype is ........... f) Percent homozygous recessive?

2. Give the ratio of the genotypes of the offspring.

3. Give the ratio of the phenotypes of the offspring.

4. What percent will have the dominant phenotype?

5. What percent will have the recessive phenotype?

C. Curley tail is dominant and straight is recessive. Use a Punnett square to show a cross between a hybrid and purebred recessive. Use the letter “T”. 1. Give the probable genotypes of the offspring: a) Homozygous dominant genotype is.......... b) Percent homozygous dominant?

c) Heterozygous genotype is....................... d) Percent heterozygous?

e) Homozygous recessive genotype is.......... f) Percent homozygous recessive?

2. Give the ratio of the genotypes of the offspring.

3. Give the ratio of the phenotypes of the offspring.

4. What percent will have the dominant phenotype?

5. What percent will have the recessive phenotype?

D. Nose hair is dominant and hair-free is recessive. Use a Punnett square to show a cross between a hybrid and another hybrid. Use the letter “N”.

1. Give the probable genotypes of the offspring: a) Homozygous dominant genotype is.......... b) Percent homozygous dominant?

c) Heterozygous genotype is....................... d) Percent heterozygous?

e) Homozygous recessive genotype is ........... f) Percent homozygous recessive?

2. Give the ratio of the genotypes of the offspring.

3. Give the ratio of the phenotypes of the offspring.

4. What percent will have the dominant phenotype?

5. What percent will have the recessive phenotype?

Bonus Cross Waxy ears are dominant and wax-free ears are recessive. Use a Punnett square to show a cross between a purebred dominant and a hybrid. Use the letter “E”.

1. Give the probable genotypes of the offspring: a) Homozygous dominant genotype is .......... b) Percent homozygous dominant?

c) Heterozygous genotype is....................... d) Percent heterozygous?

e) Homozygous recessive genotype is.......... f) Percent homozygous recessive?

2. Give the ratio of the genotypes of the offspring.

3. Give the ratio of the phenotypes of the offspring.

4. What percent will have the dominant phenotype?

5. What percent will have the recessive phenotype?