Question

bikini bottom genetics
name
scientists at bikini bottoms have been investigating the genetic makeup of the organisms in this community.
use the information provided and your knowledge of genetics to answer each question.

1. for each genotype below, indicate whether it is a heterozygous (he) or homozygous (ho).

tt __ bb dd ff tt dd __
dd __ ff tt bb bb ff __
which of the genotypes in #1 would be considered purebred? (homozygous)
which of the genotypes in #1 would be hybrids? (heterozygous)

1. determine the phenotype for each genotype using the information provided about spongebob.

yellow body color is dominant to blue.
yy __ yy yy __
square shape is dominant to round.
ss __ ss ss __

1. for each phenotype, give the genotypes that are possible for patrick.

a tall head (t) is dominant to short (t).
tall = __ short = __
pink body color (p) is dominant to yellow (p).
pink body = __ yellow body = __

1. spongebob squarepants recently met spongesusie roundpants at a dance. spongebob is heterozygous for his square shape, but spongesusie is round. create a punnett square to show the possibilities that would result if spongebob and spongesusie had children. hint: read question #2!

a. list the possible genotypes and phenotypes for their children.
b. what are the chances of a child with a square shape? __ out of or __ %
c. what are the chances of a child with a round shape? __ out of or __ %

1. patrick met patti at the dance. both of them are heterozygous for their pink body color, which is dominant over a yellow body color. create a punnett square to show the possibilities that would result if patrick and patti had children. hint: read question #3!

a. list the possible genotypes and phenotypes for their children.
b. what are the chances of a child with a pink body? __ out of or __ %
c. what are the chances of a child with a yellow body? __ out of or __ %
t. trimpe 2003 http://sciencespot.net/

Explanation:

Step1: Genotype classification (Question 1)

• Homozygous (Ho): Have two identical alleles.
• \(TT\): Two \(T\) alleles.
• \(DD\): Two \(D\) alleles.
• \(ff\): Two \(f\) alleles.
• \(tt\): Two \(t\) alleles.
• \(bb\): Two \(b\) alleles.
• \(DD\): Two \(D\) alleles.
• \(dd\): Two \(d\) alleles.
• \(BB\): Two \(B\) alleles.
• \(FF\): Two \(F\) alleles.
• Heterozygous (He): Have two different alleles.
• \(Bb\): \(B\) and \(b\) alleles.
• \(Dd\): \(D\) and \(d\) alleles.
• \(Ff\): \(F\) and \(f\) alleles.
• \(Tt\): \(T\) and \(t\) alleles.

Step2: Phenotype determination (Question 2)

• Yellow body color (dominant - \(Y\)):
• \(YY\): Yellow (homozygous dominant).
• \(Yy\): Yellow (heterozygous).
• \(yy\): Blue (homozygous recessive).
• Square shape (dominant - \(S\)):
• \(SS\): Square (homozygous dominant).
• \(Ss\): Square (heterozygous).
• \(ss\): Round (homozygous recessive).

Step3: Genotype from phenotype (Question 3)

• Tall head (\(T\) dominant to \(t\)):
• Tall: \(TT\) (homozygous dominant) or \(Tt\) (heterozygous).
• Short: \(tt\) (homozygous recessive).
• Pink body color (\(P\) dominant to \(p\)):
• Pink body: \(PP\) (homozygous dominant) or \(Pp\) (heterozygous).
• Yellow body: \(pp\) (homozygous recessive).

Step4: Punnett square for SpongeBob and SpongeSusie (Question 4)

• SpongeBob (\(Ss\) - heterozygous square) x SpongeSusie (\(ss\) - homozygous round)
• Punnett square:

	\(S\)	\(s\)
\(s\)	\(Ss\)	\(ss\)

• A. Genotypes and phenotypes:
• Genotypes: \(Ss\) (square), \(ss\) (round).
• Phenotypes: Square, Round.
• B. Square shape: \(2\) out of \(4\) or \(50\%\) (\(Ss\) occurs twice).
• C. Round shape: \(2\) out of \(4\) or \(50\%\) (\(ss\) occurs twice).

Step5: Punnett square for Patrick and Patti (Question 5)

• Both are heterozygous (\(Pp\)) for pink body color.
• Punnett square:

	\(P\)	\(p\)
\(p\)	\(Pp\)	\(pp\)

• A. Genotypes and phenotypes:
• Genotypes: \(PP\) (pink - homozygous dominant), \(Pp\) (pink - heterozygous), \(pp\) (yellow - homozygous recessive).
• Phenotypes: Pink, Pink, Yellow.
• B. Pink body: \(3\) out of \(4\) or \(75\%\) (\(PP\) and \(Pp\) occur three times).
• C. Yellow body: \(1\) out of \(4\) or \(25\%\) (\(pp\) occurs once).

Answer:

1.

• \(TT\): Ho
• \(Bb\): He
• \(DD\): Ho
• \(Ff\): He
• \(tt\): Ho
• \(dd\): Ho
• \(Dd\): He
• \(ff\): Ho
• \(Tt\): He
• \(bb\): Ho
• \(BB\): Ho
• \(FF\): Ho
• Purebred (homozygous): \(TT\), \(DD\), \(ff\), \(tt\), \(bb\), \(DD\), \(dd\), \(BB\), \(FF\)
• Hybrids (heterozygous): \(Bb\), \(Dd\), \(Ff\), \(Tt\)

2.

• \(YY\): Yellow
• \(Yy\): Yellow
• \(yy\): Blue
• \(SS\): Square
• \(Ss\): Square
• \(ss\): Round

3.

• Tall: \(TT\), \(Tt\)
• Short: \(tt\)
• Pink body: \(PP\), \(Pp\)
• Yellow body: \(pp\)

4.

• A. Genotypes: \(Ss\), \(ss\); Phenotypes: Square, Round
• B. \(2\) out of \(4\) or \(50\%\)
• C. \(2\) out of \(4\) or \(50\%\)

5.

• A. Genotypes: \(PP\), \(Pp\), \(pp\); Phenotypes: Pink, Pink, Yellow
• B. \(3\) out of \(4\) or \(75\%\)
• C. \(1\) out of \(4\) or \(25\%\)