At what stage does genetic variation increase through the recombination of alleles?

At what stage does genetic variation increase through the recombination of alleles?

• A. Metaphase 1
• B. Prophase 2
• C. Interphase 1
• D. Prophase 1

Answer: (D)

During Prophase 1 of meiosis, genetic variation increases significantly due to the process known as crossing over. This is the stage where homologous chromosomes pair up and exchange segments of their genetic material. As a result, the alleles on these chromosomes recombine, leading to new combinations that were not present in the parent organisms. This recombination is crucial for generating genetic diversity among the offspring, which is essential for evolution and adaptation. In contrast, the other stages mentioned do not contribute to the recombination of alleles in the same way. Metaphase 1 is primarily about the alignment of homologous chromosomes at the cell equator, and Interphase 1 primarily involves the replication of DNA and preparation for meiosis, without any exchange of genetic material. Prophase 2 occurs after the first meiotic division and involves separating the sister chromatids without the pairing and crossing over of homologous chromosomes seen in Prophase 1. Therefore, the significant increase in genetic variation through recombination of alleles specifically occurs during Prophase 1.

During Prophase 1 of meiosis, genetic variation increases significantly due to the process known as crossing over. This is the stage where homologous chromosomes pair up and exchange segments of their genetic material. As a result, the alleles on these chromosomes recombine, leading to new combinations that were not present in the parent organisms. This recombination is crucial for generating genetic diversity among the offspring, which is essential for evolution and adaptation.

In contrast, the other stages mentioned do not contribute to the recombination of alleles in the same way. Metaphase 1 is primarily about the alignment of homologous chromosomes at the cell equator, and Interphase 1 primarily involves the replication of DNA and preparation for meiosis, without any exchange of genetic material. Prophase 2 occurs after the first meiotic division and involves separating the sister chromatids without the pairing and crossing over of homologous chromosomes seen in Prophase 1. Therefore, the significant increase in genetic variation through recombination of alleles specifically occurs during Prophase 1.