I have a question on whole exome sequencing of cancer. I have three different cell lines from same individual cultured separately under different treatment stages (clone A before treatment, clone B after six months of treatment and clone C after 2 years of treatment). If in a SNP, I have genotype of 1/1 in clone A with (0,4) reads, 1/1 in clone B with (0,14) reads and 0/1 in clone C with (12,5) reads. Can someone please explain me what could be the possible reason and significance of such change based on the genotype and number of reference and alternate reads across different time frames of treatment in terms of gained resistance, diseases relapse or any other biological significance in these three clones.