Question

floobits are an alien species. the table below provides information about some of their physical traits. use your knowledge of genetics to complete the problems below.

characteristic	dominant gene	recessive gene
eye number	one (e)	three (e)
lip color	purple (l)	green (l)
number of fangs	one (f)	two (f)

1. use the information about floobits to fill in the phenotype for each trait.

a. tt __________ b. ll ________ c. ee ________ d. ee __________

1. use the information in the chart to write the genotypes for each trait below.

a. one eye __________ b. two fangs __________
c. short __________ d. purple lips __________

1. determine the genotypes using the information in the chart above.

a. heterozygous purple lips __________ b. homozygous one eye __________
c. hybrid one fang __________ d. purebred tall __________

1. a tall floobit named george met and fell in love with a tall floobit named marge.

a. if marge’s father is a heterozygous tall floobit and her mother is a short floobit, what is marge’s genotype? complete the punnett square to show the possible genotypes that would result to help you determine marge’s genotype.
what is marge’s genotype? ____________
b. george is heterozygous for this height.
what is his genotype? ____________
c. complete the punnett square to show the possibilities that would result if george and marge had offspring.
d. list the possible genotypes and phenotypes for the kids.
____________
e. what is the probability of tall floobit kids? ______%
f. what is the probability of short floobit kids? ______%

Explanation:

Step1: Recall dominant - recessive rules

Dominant genes show their phenotype in homozygous (two identical dominant alleles) or heterozygous (one dominant and one recessive allele) conditions. Recessive genes show their phenotype only in homozygous recessive (two identical recessive alleles) conditions.

Step2: Answer question 1

A. TT is homozygous dominant for height, so the phenotype is Tall.
B. LL is homozygous dominant for lip - color, so the phenotype is Purple.
C. ee is homozygous recessive for eye number, so the phenotype is Three eyes.
D. Ee is heterozygous for eye number, so the phenotype is One eye.

Step3: Answer question 2

A. One eye can have genotypes EE or Ee.
B. Two fangs have the genotype ff.
C. Short has the genotype tt.
D. Purple lips can have genotypes LL or Ll.

Step4: Answer question 3

A. Heterozygous purple lips have the genotype Ll.
B. Homozygous one eye has the genotype EE.
C. Hybrid one fang (heterozygous) has the genotype Ff.
D. Purebred tall has the genotype TT.

Step5: Answer question 4A

Marge's father is Tt and mother is tt. The Punnett - square:

	T	t
t	Tt	tt

Marge is tall, so her genotype is Tt.

Step6: Answer question 4B

George is heterozygous for height, so his genotype is Tt.

Step7: Answer question 4C

Punnett - square for George (Tt) and Marge (Tt):

	T	t
t	Tt	tt

Step8: Answer question 4D

Possible genotypes: TT, Tt, tt.
Possible phenotypes: Tall (TT, Tt), Short (tt).

Step9: Answer question 4E

Probability of tall flobbit kids: 75% (TT: 1/4, Tt: 2/4, so (1 + 2)/4=3/4 = 75%).

Step10: Answer question 4F

Probability of short flobbit kids: 25% (tt: 1/4 = 25%).

Answer:

1. A. Tall; B. Purple; C. Three eyes; D. One eye
2. A. EE or Ee; B. ff; C. tt; D. LL or Ll
3. A. Ll; B. EE; C. Ff; D. TT
4. A. Tt; B. Tt; C. See step 7; D. Genotypes: TT, Tt, tt; Phenotypes: Tall, Short; E. 75; F. 25