Multiple Choice
In prophase I of meiosis, allele shuffling between homologous chromosomes occurs in a process called:
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4. Genetic Mapping and Linkage
Crossing Over and Recombinants
Multiple Choice
In eukaryotic meiosis, during which stage does crossing over between homologous chromosomes occur, generating recombinant chromatids?
A
Metaphase I of meiosis I
B
Prophase II of meiosis II
C
Anaphase II of meiosis II
D
Prophase I of meiosis I (specifically pachytene)
Verified step by step guidance1
Understand that crossing over is the process where homologous chromosomes exchange genetic material, creating recombinant chromatids and increasing genetic diversity.
Recall the stages of meiosis I: Prophase I, Metaphase I, Anaphase I, and Telophase I, and note that Prophase I is subdivided into leptotene, zygotene, pachytene, diplotene, and diakinesis.
Identify that crossing over specifically occurs during the pachytene stage of Prophase I, when homologous chromosomes are fully synapsed and the exchange of genetic material takes place.
Recognize that Metaphase I involves alignment of homologous pairs at the metaphase plate, but crossing over has already occurred by this point.
Note that Prophase II and Anaphase II occur during meiosis II, which deals with separation of sister chromatids, not homologous chromosomes, so crossing over does not happen in these stages.
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