The reasons are as follows: (i) DNA sample that was loaded on the gel may have got contaminated with nuclease (exo-or endo-or both) and completely degraded. (ii) Electrodes were put in opposite orientation in the gel assembly that is anode towards the wells (where DNA sample is loaded). Since DNA moRead more
The reasons are as follows:
(i) DNA sample that was loaded on the gel may have got contaminated with nuclease (exo-or endo-or both) and completely degraded.
(ii) Electrodes were put in opposite orientation in the gel assembly that is anode towards the wells (where DNA sample is loaded). Since DNA molecules are negatively charged, they move towards
anode and hence move out of the gel instead of moving into the matrix of gel.
iii) Ethidium bromide was not added at all or was not added in sufficient concentration and so DNA was not visible.
In a gene cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector, [The step would not be affected] and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant / plasmid DNA, in tRead more
In a gene cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector, [The step would not be affected] and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant / plasmid DNA, in the absence of selectable marker, it will be difficult to distinguish between transformants and non-transformant, because role of selectable marker is in the selection of transformants.
A mixture of fragmented DNA was electrophoresed in agarose gel. After staining the gel with ethidium bromide, no DNA bands were observed. What could be the reason?
The reasons are as follows: (i) DNA sample that was loaded on the gel may have got contaminated with nuclease (exo-or endo-or both) and completely degraded. (ii) Electrodes were put in opposite orientation in the gel assembly that is anode towards the wells (where DNA sample is loaded). Since DNA moRead more
The reasons are as follows:
See less(i) DNA sample that was loaded on the gel may have got contaminated with nuclease (exo-or endo-or both) and completely degraded.
(ii) Electrodes were put in opposite orientation in the gel assembly that is anode towards the wells (where DNA sample is loaded). Since DNA molecules are negatively charged, they move towards
anode and hence move out of the gel instead of moving into the matrix of gel.
iii) Ethidium bromide was not added at all or was not added in sufficient concentration and so DNA was not visible.
You have chosen a plasmid as vector for cloning your gene. However this vector plasmid lacks a selectable marker. How would it affect your experiment?
In a gene cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector, [The step would not be affected] and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant / plasmid DNA, in tRead more
In a gene cloning experiment, first a recombinant DNA molecule is constructed, where the gene of interest is ligated to the vector, [The step would not be affected] and introduced inside the host cell (transformation). Since, not all the cells get transformed with the recombinant / plasmid DNA, in the absence of selectable marker, it will be difficult to distinguish between transformants and non-transformant, because role of selectable marker is in the selection of transformants.
See less