Answer:
By translocation of chromosome 9 and chromosome 22.
Explanation:
Acute lymphoblastic leukemia (ALL) is a type of blood cancer, which leads to increased production of immature lymphocytes.
This condition can arise due to translocation between chromosome 9 and chromosome 22. During this, ABL1 gene of chromosome 9 and BCR gene of chromosome 22 fuse together and Philadelphia chromosome.
Fusion gene made from ABL1-BCR represents an oncogene, which codes for a mutated protein. This protein causes impaired DNA binding with uncontrolled cell division that can cause cancer.
Thus, the correct answer is 'translocation.'
