2n-2 is

Options

A. Monosomic and nullisonic condition s
B. Trisomic and monosomic conditions
C. Nullisomic
D. Haploid

Answer

To solve the question "2n-2 is", we need to understand the implications of the expression "2n-2" in terms of chromosomal conditions. Here’s a step-by-step breakdown:

### Step 1: Understand the notation
- The term "2n" refers to the diploid number of chromosomes, where "n" is the haploid number. In humans, for example, n = 23, so 2n = 46.

**Hint:** Remember that "n" represents the number of chromosomes in a haploid set, while "2n" represents the total number of chromosomes in a diploid organism.

### Step 2: Analyze the expression "2n-2"
- The expression "2n-2" indicates that two chromosomes are missing from the diploid set. This means that instead of having the full diploid set (2n), there are two fewer chromosomes.

**Hint:** Think about what it means to lose chromosomes from the diploid set. How does this affect the chromosomal condition?

### Step 3: Identify the chromosomal condition
- When we subtract 2 from the diploid number (2n), we are left with a condition where there are two chromosomes missing. This condition can be classified as a form of aneuploidy.
- Specifically, if two chromosomes are missing from a diploid set, this condition is referred to as "monosomic" for those two chromosomes.

**Hint:** Recall the definitions of chromosomal conditions: monosomic means one less chromosome from a homologous pair, and if two are missing, it can be classified under a broader category of aneuploidy.

### Step 4: Evaluate the options
- **Option A: Monosomal and monosomic conditions** - This is incorrect because "monosomal" is not a standard term in genetics.
- **Option B: Trisomic and monosomic conditions** - This is incorrect because trisomic refers to having an extra chromosome, not a deletion.
- **Option C: Perisomic** - This is not a recognized term in genetics.
- **Option D: Abnormal** - This is too vague and does not specifically describe the condition.

**Hint:** Compare each option to the definitions of chromosomal conditions you have learned.

### Step 5: Conclusion
- The correct interpretation of "2n-2" is that it indicates a condition where two chromosomes are missing from the diploid set, which can be classified as a form of aneuploidy. The closest correct answer based on the options provided is that it refers to a monosomic condition.

**Final Answer:** The expression "2n-2" indicates a monosomic condition.