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#crossing over

18 public questions tagged with this topic.

Which enzyme is responsible for crossing over during meiosis?

Recombinase facilitates crossing over during the pachytene stage of prophase I in meiosis. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.

Which stage of meiosis involves crossing over?

During Prophase I, homologous chromosomes undergo crossing over, increasing genetic diversity. This follows from NCERT principle where relation explains outcome clearly for students.

Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Biology - Botany portion covering relevant concept, Topic: Plant structure, physiology and applications.

In which phase of meiosis does crossing over occur?

Crossing over occurs during prophase I of meiosis, allowing genetic recombination between homologous chromosomes. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.

Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.

What is the function of the chiasmata in meiosis?

Chiasmata become cytologically visible during diplotene and diakinesis after synaptonemal complex disassembly, appearing as cross-shaped connections between homologs under microscope. They represent late consequence of crossover recombination established chemically in pachytene between non-sister chromatids, where exchange of DNA segments creates physical interlock. Cohesion between sister chromatids distal to crossover site mediated by cohesin Rec8 maintains association, converting molecular exchange into durable tether linking homologs. This tether provides resistance to spindle pulling forc

Ref: Alberts et al., Molecular Biology of the Cell, 7th ed., Chapter 21: Chiasmata and Homolog Cohesion.

Which substage of prophase I is characterized by crossing over?

Pachytene represents longest stable meiotic prophase stage where fully synapsed bivalents thicken and crossing over implemented. Molecular hallmark is homology-directed repair of programmed double-strand breaks introduced by Spo11 topoisomerase-like transesterase in leptotene that generates 3 prime single-strand overhangs via MRE11-mediated resection. Overhangs invade homologous duplex mediated by meiosis-specific recombinases DMC1 and RAD51, forming D-loop intermediates. Decision between non-crossover and crossover fate controlled by ZMM proteins MSH4-MSH5 heterodimer stabilizing joint molecu

Ref: Hunter, Cold Spring Harb Perspect Biol 2015, Meiotic Recombination in Pachytene. Alberts 7th ed., Chapter 21.