Your Student Is Trying to Create a "Gene X" Knockout

question 28

Essay

Your student is trying to create a "Gene X" knockout mouse by introducing a recombinant construct into embryonic stem (ES) cells, selecting transformants, and introducing the transformed cells into mouse blastocysts. He designed his construct as follows:
NeoR---- region of homology to Gene X--- HSV tk- -- region of homology to Gene X where NeoR is the neomycin- resistance gene and HSV tk is the Herpes Simplex virus thymidine kinase gene. He transforms the ES cells and exposes them to G418 and ganciclovir. Explain to your student he failed to recover transformed ES cells.

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Definitions:

Dummy Variables

Numerical variables used in regression analysis to represent subgroups of the sample in a binary form.

Indicator Variable

A variable used in statistics that takes the value 1 to indicate the presence of a certain condition and 0 to indicate its absence.

Nominal Variables

Categorical variables that have two or more categories without having a natural order or rank.

College Major

The specialized area of study or field chosen by a college or university student to focus their academic coursework and degrees.