Question

Draw a diagram of the Holliday intermediate stage of the double-strand break model of recombination. Your
diagram must show each DNA strand (i.e. backbone) of all chromatids of the homologous pair of
chromosomes – use a line to represent a single strand of DNA. Specifically label:
• Chromosome(s)
• Sister chromatids(s)
• Non-sister chromatid(s)

• Holliday junction(s)
• Possible heteroduplex region(s)

Answer 1

Answer: The Holliday Model (also known as heteroduplex model) describes recombination between two homologous double-stranded molecules, those with identical or nearly identical sequences, but it is equally applicable to two different molecules that share a limited region of homology, or a single molecule that recombines with itself because it contains two separate redions that are homologous with one another.

Model for homologous recombination. Consists of the following steps:
-Nicks
-Strand Invasion
-Branch migration
-Isomerization
-Resolution (by RuvC)