can you help me explain the embedded picture

Trinucleotide Repeat Formation in Huntington's Disease Initiation of RNA Primer Synthesis 5'-CAGCAGCA-3' As you just learned, Huntington's disease occurs due to the 3'-GTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGT-5' Template Strand Replication Fork- formation of trinucleotide (CAG) repeats. These repeats can be quite large and can lead to the development of neurological diseases. GCAC Click the play button to listen to Dr. Feilotter explain the process of trinucleotide repeat formation. Upstream Slippage Slipped Strand Causes an Insertion Structure DOODOODO EE Leading Strand Direction of Synthesis 5'-CAGCAGCAGCAGCAGCAGCAG CAGCAGCAGCAGC-3' Click the icon to view 3'-GTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGT-5 Template Strand Replication Fork- the audio transcript. 00:00 ( CC E Subsequent Replication Leads to Expansion of the Trinucleotide Repeat Newly Synthesized, "Expanded" DNA Segment 5'-CAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGC-3' 3'-GTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCG-5' Original Segment of Double-Stranded DNA 5'-CAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCAGCA-3' 3'-GTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGTCGT-5' Click to enlarge