Hi guys, I am using mutation data in ICGC. There is a mutation type named "multiple base substitution". Please refer to an example at https://dcc.icgc.org/mutations/MU63993950
In a nutshell, this record says
The length of the sequence differs before and after mutation. I am wondering why substitution changes the length of sequence. Besides, why the mutated site is a single base, i.e.chr21:g.10848413 ?
So, can anybody help to explain what "multiple base substitution" is? Thanks a lot.