Question

A) If we want to use hybridization with a fluorescent probe to find say, the telomeres of each chromosome, we could use a technique called _____. The probes would bind to how many locations on each chromosome? _____

B) If you performed electrophoresis of two DNA molecules (one of 200 base-pairs and one of 250 base-pairs) on an agarose gel, would they move toward or away from the positively charged pole? Why? Which one would migrate farther away from where they both started? Why?

C) Write a rule about DNA size and electrophoresis here.

Answer 1

A) The technique which you will use is in situ hybridisation. Basically it's a technique in which you use a DNA/RNA or nucleotide sequence which is complementary to your target sequence and this complementary squence should be labelled with some dye or fluorescence. Coming to next part of the question the probe will attach to each end of the chromosomes as telomers are present on both the ends of chromosome.

B) They will move towards positive pole. As you know like charges repel each other and unlike charges attract each other. DNA being the negative charge molecule ( due to PO4- group ) it will move towards positive charge. The DNA having 200bp size will migrate farther from other as the size of this DNA molecule is less so has high mobility.

C) Rule is simple. If DNA size is more , it will cover less distance on agrose gel of electrophoresis and vice versa