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Multiple Choice
How does crossing over during meiosis increase genetic variation?
A
By exchanging segments of DNA between homologous chromosomes, creating new allele combinations.
B
By reducing the number of chromosomes in gametes, ensuring genetic diversity.
C
By duplicating entire chromosomes, leading to an increase in chromosome number.
D
By preventing mutations during DNA replication, maintaining genetic stability.
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 consecutive divisions: meiosis I and meiosis II.
Learn about homologous chromosomes: Homologous chromosomes are pairs of chromosomes that have the same structure and carry the same genes, although they may have different alleles. During meiosis I, these chromosomes pair up.
Explore the concept of crossing over: Crossing over occurs during prophase I of meiosis I when homologous chromosomes exchange segments of DNA. This process involves the physical exchange of chromosome parts between non-sister chromatids of homologous chromosomes.
Recognize the impact on genetic variation: Crossing over results in new combinations of alleles on each chromosome, which increases genetic variation in the gametes. This genetic variation is crucial for evolution and adaptation.
Differentiate crossing over from other processes: Unlike chromosome duplication or mutation prevention, crossing over specifically contributes to genetic diversity by creating new allele combinations, not by changing chromosome number or preventing mutations.