Tt mates with tt. What will be characteristic of offsprings?

Options

A. 75% recessive
B. 50% recessive
C. 25% recessive
D. All dominant

Answer

To determine the characteristics of the offspring when Tt (heterozygous) mates with tt (homozygous recessive), we can follow these steps:

### Step 1: Identify the Genotypes of the Parents
- One parent has the genotype Tt (heterozygous).
- The other parent has the genotype tt (homozygous recessive).

### Step 2: Set Up a Punnett Square
- Create a 2x2 Punnett square to visualize the possible combinations of alleles from the parents.
- The alleles from the Tt parent (T and t) will be placed on one side of the square, and the alleles from the tt parent (t and t) will be placed on the other side.

### Step 3: Fill in the Punnett Square
- The combinations will be:
- Top left: T (from Tt) and t (from tt) = Tt
- Top right: t (from Tt) and t (from tt) = tt
- Bottom left: T (from Tt) and t (from tt) = Tt
- Bottom right: t (from Tt) and t (from tt) = tt

The completed Punnett square looks like this:

| | t | t |
|-----|-----|-----|
| T | Tt | Tt |
| t | tt | tt |

### Step 4: Analyze the Offspring Genotypes
- From the Punnett square, we see the following genotypes:
- 2 Tt (heterozygous)
- 2 tt (homozygous recessive)

### Step 5: Determine the Phenotypic Ratio
- The Tt genotype expresses the dominant trait, while the tt genotype expresses the recessive trait.
- Therefore, the phenotypic ratio of the offspring is:
- 50% dominant (Tt)
- 50% recessive (tt)

### Conclusion
The characteristics of the offspring from the cross Tt x tt will be:
- 50% will show the dominant trait (Tt).
- 50% will show the recessive trait (tt).