What will be the distribution of phenotypic features in the first generation after a cross between a homozygous female and a heterozygous male for a single locus ?

Options

A. `3:1`
B. `1: 2: 1`
C. `1: 1`
D. none of these

Explanation

To determine the distribution of phenotypic features in the first generation after a cross between a homozygous female and a heterozygous male for a single locus, we can follow these steps:

### Step 1: Identify the Genotypes
- **Homozygous Female**: Let's denote the homozygous female as **tt** (where 't' represents the recessive allele).
- **Heterozygous Male**: The heterozygous male can be denoted as **Tt** (where 'T' represents the dominant allele and 't' represents the recessive allele).

### Step 2: Determine Gametes
- The homozygous female (tt) can only produce one type of gamete: **t**.
- The heterozygous male (Tt) can produce two types of gametes: **T** and **t**.

### Step 3: Create a Punnett Square
- Set up a Punnett square to visualize the potential offspring from the cross:

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

### Step 4: Analyze the Offspring Genotypes
- From the Punnett square, we can see the possible genotypes of the offspring:
- **Tt** (tall) - 2 occurrences
- **tt** (dwarf) - 2 occurrences

### Step 5: Determine the Phenotypic Ratio
- The phenotypes corresponding to the genotypes are:
- **Tt**: Tall (dominant phenotype)
- **tt**: Dwarf (recessive phenotype)

- Thus, the phenotypic distribution is:
- Tall: 2
- Dwarf: 2

### Step 6: Calculate the Phenotypic Ratio
- The ratio of tall to dwarf plants is 2:2, which simplifies to **1:1**.

### Conclusion
The distribution of phenotypic features in the first generation after a cross between a homozygous female and a heterozygous male for a single locus will be **1:1** (tall to dwarf).