A Molecular Technologist Has Run a Vertical Gel

Multiple Choice

A molecular technologist has run a vertical gel. While analyzing the gel, the technologist notices that the bands in the outer lanes did not run as far as similar-sized bands in the inner lanes, so the bands look like a smile on the gel. What is the explanation for this?

A) Samples were loaded into the inner wells first and got a head start moving down the gel.
B) A larger volume of sample was loaded into the outer wells so that they ran slower.
C) The electrodes in the middle of the gel were working better than at the edges of the gel.
D) The temperature across the gel was not constant, so the inner wells were warmer.