Multiple Choice
In what stage of meiosis does crossing over (homologous recombination) primarily occur?
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4. Genetic Mapping and Linkage
Crossing Over and Recombinants
Multiple Choice
In meiosis I, what are the visible crossover points where non-sister chromatids exchange segments called?
A
Synaptonemal complexes
B
Kinetochores
C
Centromeres
D
Chiasmata
Verified step by step guidance1
Understand that during meiosis I, homologous chromosomes pair up and exchange genetic material to increase genetic diversity.
Recognize that the physical sites where non-sister chromatids exchange segments are visible under a microscope as points of contact.
Recall that these visible crossover points are called chiasmata (singular: chiasma), which hold homologous chromosomes together after crossing over.
Differentiate chiasmata from other structures: synaptonemal complexes are protein structures that form between homologous chromosomes earlier in prophase I; kinetochores are protein complexes at centromeres where spindle fibers attach; centromeres are the constricted regions of chromosomes.
Conclude that the correct term for the visible crossover points where non-sister chromatids exchange segments during meiosis I is chiasmata.
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