During meiosis I, crossing over can occur. What is the most common result of crossing over?

• A. Reduction in chromosome number
• B. Increased genetic variation in gametes
• C. Formation of identical sister chromatids
• D. Production of diploid gametes

Answer: (B)

Verified step by step guidance

1. Understand the process of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the production of gametes (sperm and eggs). It consists of two stages: meiosis I and meiosis II.
2. Learn about crossing over: Crossing over occurs during prophase I of meiosis I. It involves the exchange of genetic material between homologous chromosomes, which are pairs of chromosomes containing the same genes but possibly different alleles.
3. Recognize the role of crossing over: The primary purpose of crossing over is to increase genetic variation. By exchanging segments of DNA, new combinations of alleles are created, which contribute to genetic diversity in the resulting gametes.
4. Differentiate between the options: Reduction in chromosome number is a result of meiosis overall, not specifically crossing over. Formation of identical sister chromatids occurs during DNA replication, not crossing over. Production of diploid gametes is incorrect because meiosis produces haploid gametes.
5. Conclude the most common result: The most common result of crossing over during meiosis I is increased genetic variation in gametes, as it creates new combinations of alleles that contribute to the diversity of offspring.