$4$

Multiple Choice

$2$ points

Chronic myelogenous leukemia is caused by a translocation between chromosomes $9$ and $22$ that creates a fusion gene that contains parts of the BCR and ABL genes. This fusion gene maintains the kinase ability of ABL but is regulated and localized differently than ABL, leading to overactivation and cancer signaling. This sequence of events is possible because:

This is an example of horizontal gene transfer

Protein design is modular, with different parts of the polypeptide sequence responsible for different aspects of a protein's regulation and function

The $BCR$ and ABL genes are orthologs

The translocation causes a loss of function mutation