KRAS is the best-known oncogene (i.e. its mutation result in cancer) with the highest
mutation rate among various cancers. To study how the famous G12S KRAS mutation (Glycine
at 12th amino-acid is replaced to Serine) induce cell proliferation, you are creating a KRAS
G12S cell line, which contains a reduced level of wildtype KRAS, while expressing KRAS G12S.
Describe your method of establishing the mutant cell line, starting from the wildtype cell and
using the recombinant DNA plasmid.
â—‹ We need to transfect cells with two separate plasmids, one containing shRNA that knock down wildtype KRAS, another that overexpresses KRAS mutant. The
first step can be replaced with CRISPR-Cas9.
 In scRNAseq, what are the roles of UMI and Bcd?
 At what stage does cDNA fragmentation occur in scRNA-seq, and why is it important?
â—‹ cDNA fragmentation in scRNA-seq occurs during library preparation, after reverse transcription and amplification. Since most scRNA-seq methods are 3'- or 5'-