During meiotic prophase in a eukaryotic cell, Spo11 initiates recombination by causing a double-strand break in DNA between Gene A and Gene B on one sister chromatid.Which of these events will occur prior to formation of a Holliday junction?
A)A heteroduplex forms due to pairing of Gene A and Gene B.
B)Resolvase cuts all four chromatids.
C)Spo11 causes a double-strand break in a nonsister chromatid.
D)Strand invasion causes one strand of the uncut chromatid to form a D loop.
E)Branch migration lengthens the heteroduplex region to include Gene A and Gene B.

Question

Quizplus · Accepted Answer

Strand invasion, which leads to the formation of a D loop, is a critical step that occurs after Spo11 induces a double-strand break but before the formation of a Holliday junction. This process involves one of the single strands from the broken DNA invading a homologous sequence on a nonsister chromatid, which is essential for homologous recombination and the eventual formation of a Holliday junction.

During Meiotic Prophase in a Eukaryotic Cell, Spo11 Initiates Recombination