Conditions of a karyotype `2n pm 1 and 2n pm 2` are called

Options

A. aneuploidy
B. polyploidy
C. allopolyploidy
D. monosomy

Explanation

To solve the question regarding the conditions of a karyotype represented as `2n ± 1` and `2n ± 2`, we can follow these steps:

### Step 1: Understand Karyotype Notation
- The notation `2n` represents the diploid number of chromosomes in an organism, where `n` is the basic set of chromosomes.
- The terms `2n + 1` and `2n - 1` indicate an increase or decrease in the number of chromosomes, respectively.

### Step 2: Identify the Types of Changes
- The conditions `2n - 1` (monosomy) and `2n - 2` (nullisomy) indicate a loss of chromosomes.
- The conditions `2n + 1` (trisomy) and `2n + 2` (tetrasomy) indicate an increase in chromosomes.

### Step 3: Define the Type of Mutation
- These changes in chromosome number are classified as genomic mutations. Specifically, they fall under the category of **aneuploidy**.
- Aneuploidy refers to a condition where the number of chromosomes is not an exact multiple of the haploid set (n).

### Step 4: Explain the Mechanism
- The primary cause of aneuploidy is **non-disjunction**, which is the failure of homologous chromosomes to separate properly during cell division.
- This can lead to gametes with an abnormal number of chromosomes, resulting in conditions like monosomy (missing one chromosome) or trisomy (having an extra chromosome).

### Step 5: Conclude with Examples
- Examples of conditions resulting from aneuploidy include:
- **Down syndrome** (trisomy 21) - an extra chromosome 21.
- **Turner syndrome** (monosomy X) - a missing X chromosome in females.

### Final Answer
The conditions of a karyotype `2n ± 1` and `2n ± 2` are called **aneuploidy**.

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