Bikini Bottom Genetics Review

Bikini Bottom Genetics Review

Genetic Terms and Definitions

  • Homozygous (Ho)

    • Definition: Organisms with two identical alleles for a trait.

    • Example: BB (Purebred)

    • Also referred to as purebred

  • Heterozygous (He)

    • Definition: Organisms with two different alleles for a trait.

    • Example: Bb (Hybrid)

  • Alleles

    • Definition: Different versions of a gene that can exist at a specific locus on a chromosome.

    • Example: For the gene that determines body color, alleles might be Y (yellow) and y (blue).

  • Genotype

    • Definition: The genetic makeup of an organism represented by pairs of letters (alleles).

    • Example: TT, Bb, or Rr.

  • Phenotype

    • Definition: The physical appearance or observable traits of an organism.

    • Example: A yellow body or round eyes.

Classification of Gene Pairs

  • Characteristics Classification:

    • Body Shape:

    • TT - Homozygous (Ho)

    • Bb - Heterozygous (He)

    • Body Color:

    • dd - Homozygous (Ho)

    • Ff - Heterozygous (He)

    • Eye Shape:

    • Rr - Heterozygous (He)

Possible Genotypes for Traits

  • Purebred Squarepants:

    • Genotype: SS

  • Blue Body Color:

    • Genotype: xx

  • Round Eyes:

    • Possible Genotypes:

    • Rr

    • RR

    • Ss

Phenotypes for Each Genotype

  • SS (Homozygous) -

    • Phenotype: Squarepants, Yellow body

  • TT (Homozygous) -

    • Phenotype: Round eyes

  • Rr (Heterozygous) -

    • Phenotype: Round eyes

  • dd (Homozygous) -

    • Phenotype: Roundpants

  • Ff (Heterozygous) -

    • Phenotype: Yellow body

Punnett Square Analysis for SpongeJimBob's Offspring

  • Scenario:

    • SpongeJimBob is a heterozygous yellow sponge with genotype Yy.

    • His spouse is a blue sponge with genotype yy.

  • Punnett Square:

         Y      |      y  
      -----------------  
    Y |    YY   |   Yy  
      -----------------  
    y |    Yy   |   yy

  • Possible Genotypes for Offspring:

    • 2 heterozygous (Yy)

    • 2 homozygous recessive (yy)

  • Phenotypes of Offspring:

    • 50% Yellow (YY or Yy)

    • 50% Blue (yy)

Punnett Square Analysis for Eye Shape

  • Scenario:

    • SpongeJimBob has oval eyes (Rr) and his spouse is homozygous for round eyes (RR).

  • Punnett Square:

         R      |      R  
      -----------------  
    R |    RR   |   RR  
      -----------------  
    r |    Rr   |   Rr

  • Possible Genotypes for Offspring:

    • 100% Heterozygous for round eyes (RR or Rr)

  • Percentage with Round Eyes:

    • 100%

  • Percentage with Oval Eyes:

    • 0%