Home
Class 12
BIOLOGY
Crossing over occurs at...

Crossing over occurs at

A

Single strand satge of chroomosmes during propase

B

Two strand stage during zygotene

C

Metaphase II of meiosis

D

Four strand stage

Text Solution

AI Generated Solution

The correct Answer is:
**Step-by-Step Solution:** 1. **Understanding Crossing Over**: - Crossing over is a genetic process that occurs during meiosis, where homologous chromosomes exchange segments of genetic material. This increases genetic diversity in gametes. 2. **Identifying the Stage of Meiosis**: - Meiosis consists of two main stages: Meiosis I and Meiosis II. Crossing over specifically occurs during Meiosis I. 3. **Recognizing the Relevant Phase**: - Within Meiosis I, crossing over occurs during Prophase I. This phase can be further divided into several sub-stages: Leptotene, Zygotene, Pachytene, Diplotene, and Diakinesis. 4. **Focusing on the Correct Sub-stage**: - The actual exchange of genetic material occurs during the Pachytene stage of Prophase I, where homologous chromosomes are closely aligned and form structures called tetrads (or bivalents), consisting of four chromatids (two from each homologous chromosome). 5. **Conclusion**: - Therefore, crossing over occurs at the 4-strand stage, which refers to the tetrad formation during the Pachytene stage of Prophase I in meiosis. **Final Answer**: Crossing over occurs at the 4-strand stage during the Pachytene phase of Prophase I in meiosis. ---
Promotional Banner

Topper's Solved these Questions

  • CHROMOSOMAL BASIS OF INHERITANCE

    DINESH PUBLICATION ENGLISH|Exercise Check Your Grasp|57 Videos

  • CHORDATA- PROTOCHORDATA

    DINESH PUBLICATION ENGLISH|Exercise CYG|11 Videos

  • COELENTERATA AND CTENOPHORA (OR CNIDARIA AND ACNIDARIA)

    DINESH PUBLICATION ENGLISH|Exercise CYG|10 Videos

Similar Questions

Explore conceptually related problems

Crossing over occurs between

Crossing over occurs between ........... Chromatid of ......... chromosome.

Two homologous chromosomes are depicted in the diagram given below. Crossing over occurs between chromatid 2 and chromatid 3 at the point as depicted . The gametes produced as a result of this crossing over will be

Crossing-over occurs in the

During meiosis, crossing over occurs between

Crossing over occurs during (a) Pachytene (b) Diplotene (c) Diakinesis (d) Zygotene

In Drosophila crossing over occurs in female but not in male. Gene A and B are 10 map unit apart on chromsome. A female Drosphila with genotype (AB)/(ab). and male Desphila with genotype (AB)/(ab). How many type of gametes are produced by female and male Droaphila respectively

Segregation of Mendelian factors (no linkage no crossing over) occurs during:

Match List I and List II and select the correct answer using the code given below in the lists: {:("List I (Phase of meiosis)","List II (Event that occurs)"),("Prophase I","Crossing over occurs"),("Metaphase I","Sister chromatids migrate to opposite poles"),("Anaphase I","Homologous line up at equator in pairs"):}

Synapsis or crossing over occuring in meiosis I at pachytene stage ; occurs between