The exchange of genetic material between chromatids of paired homologous chromosomes during first meiotic division is called

Options

A. transformation
B. chiasmata
C. crossing over
D. synapsis

Explanation

**Step-by-Step Solution:**

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the formation of gametes (sperm and eggs). It consists of two successive divisions: meiosis I and meiosis II.

2. **Homologous Chromosomes**: During meiosis, homologous chromosomes (chromosomes that are similar in shape, size, and genetic content) pair up. Each chromosome consists of two sister chromatids.

3. **Pachytene Stage**: In the first meiotic division, specifically during the pachytene stage of prophase I, the paired homologous chromosomes undergo a significant process.

4. **Non-Sister Chromatids**: The chromatids of homologous chromosomes are referred to as non-sister chromatids. For example, if we have two homologous chromosomes, each consisting of two sister chromatids, the chromatids from different chromosomes are non-sister chromatids.

5. **Crossing Over**: During the pachytene stage, these non-sister chromatids exchange segments of genetic material. This process is known as crossing over. It is crucial for genetic diversity as it results in new combinations of alleles.

6. **Result of Crossing Over**: After crossing over, the chromatids will have segments from each other. This genetic recombination is essential for evolution and adaptation in populations.

7. **Conclusion**: Therefore, the exchange of genetic material between chromatids of paired homologous chromosomes during the first meiotic division is called **crossing over**.

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