REVIEW PUNNETT SQUARES

How many alleles are needed to represent a trait? 2

one allele from each parent When Gregor Mendel crossed a purple plant with a white plant, the offspring inherited one allele from each parent

CODOMINANCE

INCOMPLETE DOMINANCE

INCOMPLETE DOMINANCE Genotypes? RR WW RW

OO BB Genotypes? CODOMINANCE BO

CODOMINANCE Genotypes? RR BB RB

INCOMPLETE DOMINANCE Genotypes? RR WW RW

1. If the alleles for the color of a flower are rr , what is true of its parents? The genotype of both parents contained a recessive allele. Rr and Rr or Rr and rr

2. A man with type A blood and a woman with type B blood have a type O child. What are the genotypes of the parents? Man is IAi Woman is IBi

3. A woman who is type B has children with a man who is type O. They have both type B and type O children. What are the genotypes of the parents? Woman is IBi Man is ii

Wavy hair 4. In humans, the allele C (curly hair ) exhibits incomplete dominance over the allele S (straight hair). What type of hair will an individual with genotype CS have? Wavy hair The phenotype would be intermediate between the two.

5.  Two parents are found to be carriers of a genetic disorder caused by a recessive allele (m). Offspring born with two recessive alleles die before becoming old enough to reproduce. What is the likelihood of these parents having an offspring with the disorder? mm Mm Mm ? X

6. B b In squirrels, brown fur color is dominant to gray. A male brown squirrel and a female gray squirrel mate. They have both brown babies and gray babies. What is the genotype of the male parent?

? G g Gg gg 7. Green is dominant to yellow. A hybrid green plant is crossed with a yellow one. What % of the offspring are yellow? ? Gg gg X

? codominance BB YY BY BB BY 8. Genotypes? BB YY BY X Blue petunias crossed with yellow petunias produces blue and yellow petunias. This is an example of codominance When a blue petunia and a blue and yellow petunia are crossed, the genotypic ratios of the offspring are: Genotypes? BB BY ? X

9. Y In daisies, yellow flower color is dominant to white. You cross a plant with white flowers with a plant heterozygous for yellow flowers. What percent of the offspring would have white flowers? y yy Yy ? X If these two plants produced 1000 offspring, how many would be white? 500

BB YY BY BY YY ? 10. Incomplete dominance When a plant with blue flowers mates with a plant with yellow flowers, all the offspring produced are green. This is an example of Incomplete dominance BB YY BY X A plant with green flowers mates with a plant with yellow flowers. What percent of the plants produced will have yellow flowers? BY YY ? X

11. B b Black fur color is dominant and brown fur color is recessive. A black mouse is crossed with a brown mice. The offspring is brown. What is the genotype of the black mouse? bb Bb

12. T t A tan monkey is mated with a white monkey. All of their offspring are tan. What are the genotypes of the parents? What are the genotypes of the offspring? TT , tt Tt If two of these tan offspring are mated, what fraction of their offspring will be white? ? Tt Tt X

13. B represents brown feathers, and b represents white feathers. Bb mates with Bb. What are the chances of producing a bird with brown feathers? Bb Bb ? X