Predicting Phenotypes and Genotypes Heterozygous – Is there a predictable result when both parents are heterozygous? Homozygous – is there a predictable result when both parents are homozygous?

Types of Questions 1)Green eyes/ yellow eyed fruit flies 2)Brown/black wolves 3)Find parents genotypes 4)Curly haired babies 5)Parents and grandparents 6)Snakes 7) Donkeys 8) Noses 9) Short/tall 10) Short neck/long neck 11) Short/longue tongues

Punnett Squares

The tool which uses the combination of alleles to predict the probability of traits showing up in offspring.

1) Green eyes are dominant and yellow eyes are recessive. The genotype of two insects are Gg and Gg. Complete a Punnett square!

Genotype and Phenotypes Genotypes What are the chances that the offspring will have the following genotypes? GG? Gg? gg? Phenotypes Give the percentages of the offspring which will have the following phenotypes: Green eyes _____ Yellow eyes _____

Answer When you have tried it…

G Gg Gg GG g G g ?? ?? = gg

What % of the young would have green eyes? Yellow eyes? 75% 25%

What % of the young would have GG? (1 out of 4) 25% Gg? 50% gg? 25%

2) Show the result of crossing (mating/breeding) two wolves. The female is heterozygous Bb and the male is homozygous bb. Complete a Punnett square!

What % of young would be black and what % would be brown? Black = 50 % Brown = 50 %

Answer When you have tried it…

B Bb bb Bb b b b bb

3) B=Brown eyes which are dominant b=blue eyes which are recessive What are the alleles of the parents for the following chart?

B Bb Bb BB b B b bb

Answer When you have tried it…

The parents would be Bb and Bb and both would have brown eyes!

4) Curly hair is dominant, and a couple both have curly hair. What are the chances that their children will have curly hair?

A. All of the babies B. At least 75% of the babies C. At least 50% of the babies D. None of the babies

Answer After you have tried it….

C Cc Cc CC c C c cc Even if the parents were heterozygous for curly hair… 75% of the offspring would have curly hair (CC or Cc – both of these genotypes give the phenotype of curly hair)

5) What percent of your genes come from each parent? 50%

5) Continued What % of genes come from each grandparent? 25%

6) If green snake skin is dominant and yellow is recessive, what are the alleles of the parent snakes for the following:

Answer When you are ready…

G Gg Gg Gg g g G Gg

Homozygous (GG) green Homozygous (gg) yellow

7) In donkeys, if big ears are dominant and both parents are homozygous dominant, what percent of babies will have big ears?

E EE EE EE E E E EE

100%

Answer When you are ready…

Three fingers is dominant and five fingers recessive. If mom is homozygous dominant and dad is heterozygous, what percent of young will have three fingers?

F Ff FF FF f F F Ff

100%

8) Big noses are dominant and little noses are recessive. If Dad is homozygous dominant and mom is homozygous recessive, what percent of children will have big honkers?

N Nn Nn Nn n n N Nn

100%

9) Short is dominant and tall is recessive. If dad is heterozygous dominant and mom is homozygous recessive, what percent of the children will be short and tall?

S Ss’ s’s’ Ss’ s’ s’s’

50% short 50% tall

10) Long neck is dominant and short neck is recessive. If dad is heterozygous dominant and mom is heterozygous dominant, what percent of the children will have long necks and short necks?

N Nn Nn NN n N n nn

75% Long 25% Short

11) Short tongues are dominant and long are recessive. If mom is homozygous recessive and dad is homozygous recessive, what percent of the children will have long tongues?

t tt tt tt t t t tt

100%

Thank you