Question

investigation question:
what is the likelihood that the offspring of a heterozygous male (ff) and a heterozygous female (ff) have offspring with yellow fur?
we can use punnett squares to determine the probability (likelihood) of an offsprings traits.
a punnett square has four sections totaling up to represent a 100% chance to occur. each section represents one possible offspring combination for a trait and a ________ chance to occur.

1. write the female parents allele combination along the left side of the square with one letter next to one square.

(mothers combination is ff)

1. write the male parents allele combination along the top of the square with one letter above one square.

(fathers combination is ff)

1. in each box, pull the letter from the left and the letter from the top to form a possible allele combinations.

making sense of the punnett square:
write the four possible genotype combinations from your punnett square above:

Explanation:

Step1: Recall Punnett Square Basics

A Punnett Square with 4 sections means each section has a probability of $\frac{1}{4}$ (or 25%) since $1\div4 = 0.25$ (25%).

Step2: Set Up Parent Alleles

Mother (Ff) has alleles F and f (left side: F next to one square, f next to the other). Father (Ff) has alleles F and f (top: F above one square, f above the other).

Step3: Fill Punnett Square

• Top - left: F (from top) and F (from left) → FF
• Top - right: F (from top) and f (from left) → Ff
• Bottom - left: f (from top) and F (from left) → Ff
• Bottom - right: f (from top) and f (from left) → ff

Step4: Determine Genotype Counts

• FF: 1 out of 4
• Ff: 2 out of 4
• ff: 1 out of 4

Step5: Relate Genotype to Phenotype (Yellow Fur)

Assume F is dominant (yellow fur), so FF and Ff show yellow fur. Total favorable (FF + Ff) = 1 + 2 = 3 out of 4.

Step6: Calculate Probability

Probability = $\frac{\text{Number of favorable genotypes}}{\text{Total genotypes}}=\frac{3}{4}$ (or 75%).

Answer:

The likelihood (probability) that the offspring will have yellow fur is $\frac{3}{4}$ (or 75%).

Filling the Blanks (From the Worksheet):

• Each section chance: 25% (or $\frac{1}{4}$)
• FF: 25% (yellow, assuming F is dominant)
• Ff: 50% (yellow, since F is dominant)
• ff: 25% (non - yellow, recessive)
• Four genotypes: FF, Ff, Ff, ff
• Chances for each:
• FF: 25% chance, yellow fur.
• Ff (first): 25% chance, yellow fur.
• Ff (second): 25% chance, yellow fur.
• ff: 25% chance, non - yellow fur.
• Overall yellow fur chance: 75% (3 out of 4)