Which of the following answers is neither involved with crossing over nor an outcome of crossing over?

• A. The DNA in two nonsister chromatids is broken by specific proteins at exact points.
• B. Chiasmata indicate where crossing over is occurring between homologs.
• C. Recombination leads to the formation of chromosomes containing paternal and maternal alleles.
• D. All of the listed responses pertain to the process of crossing over.
• E. Independent assortment results from the random alignment of homologous pairs of chromosomes at metaphase I.

Answer: (E)

Verified step by step guidance

1. Understand the concept of crossing over: Crossing over is a process during meiosis where homologous chromosomes exchange genetic material. This occurs during prophase I of meiosis and results in genetic recombination.
2. Identify the role of nonsister chromatids: During crossing over, the DNA in two nonsister chromatids is broken and rejoined, leading to the exchange of genetic material. This is a key part of the crossing over process.
3. Recognize the significance of chiasmata: Chiasmata are the visible manifestations of crossing over, indicating where the exchange of genetic material has occurred between homologous chromosomes.
4. Understand recombination: Recombination is the outcome of crossing over, resulting in chromosomes that contain a mix of paternal and maternal alleles, increasing genetic diversity.
5. Differentiate independent assortment: Independent assortment is a separate process from crossing over. It refers to the random alignment of homologous chromosome pairs during metaphase I of meiosis, leading to the random distribution of maternal and paternal chromosomes into gametes. This is not directly related to crossing over.