I need help interpreting this gel? I am confused to what all the numbers on the

Question

I need help interpreting this gel? I am confused to what all the numbers on the gene ruler mean and how I can talk about my results. I performed an isolation of pRecA/pUC19 plasmid DNA followed by a Digestion of pRecA/pUC19 plasmid DNA with BamHI. Thank you 527281802 FAU S/25/2018 12:36:42 PM Dye Ethidium Bromide: Lights TLUM N Wave: Filter UV06 GeneRuler 1 kb DNA Ladder 10000 30 6 8000 30 6 6000 70 14 5000 30 6 4000 30 6 3500 30 6 3000 70 14 3500 1500 25 5 1000 60 12 750 25 5 500 25 5 -250 25 5 0.5 ugane, 8 cm length gel, 1X TAE, 7 V/cm, 45 m

Explanation / Answer

The gene ruler shown here is a 1kilo base pairs i.e 1 kb DNA ladder 1kb= 1000 bases ( this is the lowest accurate measure by using this gene ruler).

In molecular biology DNA or plasmid DNA are composed of bases. These DNA when digested by some restriction endonucleases produces small fragments of DNA which are several basepair long. The number of these base pairs denotes the actual size of the fragment produced.

A gene ruler contain known base pair sizes and hence are run along with the unknown sample to determine the size of that sample by the position of band that comes parallel to the gene ruler band.

Hence the bp size mentioned on the gene ruler from 1000 to 10,000 bases are actual length of the fragments in that gene ruler.

Second column which denotes ng/0.5 microgram in the range of 25-70 denotes the concentration of each band contained in the ruler. For example the concentration of 1000 basepair band is 60ng when 0.5microgram of DNA ladder is loaded on 1% agarose gel.

Third column on the DNA ladder denotes the percentage of each band in the whole ladder i.e 1000 bp band constitutes 12% of the total ladder, 3000 bp band constitutes 14%, 6000 bp band also constitutes 14% and so on.

So to interpret the results from the gel picture the no. of band, which is parallel to the unknown band in DNA ladder is counted, starting from the bottom and then from the DNA ladder chart the base pair size is determined.

Here in this case it is recommended that the 1kb ladder and BamH1 digested pRecA/pUC19 plasmid DNA fragments should be run on 1% agarose gel rather than 0.8% to found the band size accurately and this will also enhance the band sharpness and resolution too.

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