Question

Using SpongeBob's and Carolina Seafoam's life story, create a Five-generation pedigree chart tracking the trait of glowing freckles.

(Pedigree Chart: Pedigree Chart Link Links to an external site.OR Write it out on paper)

Students must include:

Names of each member in the pedigree
Correct Shapes for each member (Males= Square, Females= Circle)
Include Geneotypes for each member ( Using the letter "G" for glowing freckles)
Include the generation numbers on the outside of each generation
Hint:

GG and Gg = Glowing freckles

gg = No Glowing Freckles

Story:



SpongeBob SquarePants had always wondered why he had tiny glowing blue freckles that shimmered whenever he laughed. No one else he knew had them. Until the day he met Coralina Seafoam, a friendly marine biologist jellyfish-wrangler who had just moved to Bikini Bottom.

Coralina had the same glowing blue freckles.

When SpongeBob asked about them, Coralina explained that the freckles were a family trait passed down through generations. She told him that in her family, the glowing freckles were dominant, meaning you only needed one copy of the gene to show the trait.

SpongeBob was amazed. Coralina invited him to meet her family so he could learn more about them.



Coralina’s Family History

Coralina’s parents were:

Mother: Marina Seafoam — had glowing freckles
Father: Tide Seafoam — did not have glowing freckles
Marina told SpongeBob that the freckles came from her side of the family. She showed him old portraits of ancestors who had passed away long before SpongeBob was born:

Great‑Grandmother Pearlina — glowing freckles (deceased)
Great‑Grandfather Barnacle Bill — no freckles (deceased)
Grandmother Shelly Seafoam — glowing freckles (deceased)
Grandfather Reef Seafoam — glowing freckles (deceased)


SpongeBob noticed a pattern: the freckles kept appearing in almost every generation.

SpongeBob and Coralina Start a Family

Over time, SpongeBob and Coralina became close friends, then partners, and eventually started a family of their own. They had three children:

Bubblebeard — glowing freckles
Sandyfin — glowing freckles
Finnbert — no freckles
When their children grew up, they had kids of their own:

Bubblebeard’s children: one with freckles, one without
Sandyfin’s children: both with freckles
Finnbert’s children: none with freckles
SpongeBob realized he had discovered something amazing: the glowing freckles trait could be traced back five generations, to ancestors who lived long before he was born.

Answer 1

Below is a written five-generation pedigree (text version) for glowing freckles (G = glowing allele; gg = non‑glowing). I list each generation (I–V) on the left, each person with sex (shape), name, phenotype, and inferred genotype. Males = square, Females = circle (I indicate shape in parentheses).

Notes used to infer genotypes:
- Glowing is dominant: GG or Gg = glowing, gg = no glowing freckles.
- Any glowing child of a non‑glowing parent must be heterozygous (Gg) if the other parent is gg.
- Two glowing (heterozygous) parents (Gg × Gg) can produce GG, Gg, or gg offspring (25% gg expected).

Generation I (oldest great‑grandparents)
- Pearlina (circle — female) — glowing freckles — genotype: Gg
- Barnacle Bill (square — male) — no freckles — genotype: gg
(Reason: Pearlina is glowing and Barnacle Bill is non‑glowing; their glowing descendant must carry one G from Pearlina → Pearlina is at least Gg.)

Generation II (grandparents)
- Shelly Seafoam (circle — female) — glowing freckles — genotype: Gg
- Reef Seafoam (square — male) — glowing freckles — genotype: Gg
(Reason: Shelly is a child of Pearlina (Gg) × Barnacle Bill (gg); Shelly must be Gg to be glowing. Reef is described as glowing; assigning Gg fits the observed pattern of recurring freckles.)

Generation III (parents)
- Marina Seafoam (circle — female) — glowing freckles — genotype: Gg
- Tide Seafoam (square — male) — no freckles — genotype: gg
(Reason: Marina is descendant of two glowing grandparents (Shelly, Reef) but Marina’s partner Tide is non‑glowing (gg) and their glowing child Coralina shows the dominant allele was passed — Marina is assigned Gg.)

Generation IV (proband couple)
- Coralina Seafoam (circle — female) — glowing freckles — genotype: Gg
- SpongeBob SquarePants (square — male) — glowing freckles — genotype: Gg
(Reason: Coralina is child of Marina (Gg) × Tide (gg) → Coralina must be Gg. SpongeBob is glowing and, because one of Coralina & SpongeBob’s children (Finnbert) is non‑glowing, SpongeBob must be a carrier (Gg) so Gg × Gg can yield a gg child.)

Generation V (their children)
- Bubblebeard (square — male) — glowing freckles — genotype: Gg
- Sandyfin (circle — female) — glowing freckles — genotype: Gg
- Finnbert (square — male) — no freckles — genotype: gg
(Reason: From Coralina (Gg) × SpongeBob (Gg) the offspring probabilities include GG/Gg/gg. The story’s children (two glowing, one non‑glowing) are consistent with Bubblebeard = Gg, Sandyfin = Gg, Finnbert = gg.)

Extra next‑generation (children of Generation V — listed but beyond the five generations of the main chart)
- Bubblebeard’s children: one with freckles (Gg), one without (gg).
- Sandyfin’s children: both with freckles (GG or Gg — at least G_).
- Finnbert’s children: none with freckles (all gg) — consistent with Finnbert = gg (if spouses are gg or none gave G).

How to draw this as a pedigree:
- Draw generations I → V left to right (or top to bottom). Place spouses side‑by‑side with a horizontal line between them; vertical lines down to their children. Use circles for females and squares for males. Write each person’s name under their symbol and their genotype (e.g., Coralina: Gg) next to or below the name. Label generations I, II, III, IV, V on the outside of the chart.

If you want, I can:
- Produce a simple ASCII pedigree layout, or
- Create a downloadable image (PNG/SVG) of the pedigree with correct shapes/genotypes and generation numbers. Which would you prefer?