Question about Northern Blot - (Dec/18/2013 )

I would be very grateful if someone provided me some hints to tackle this problem:

A human gene with 4 exons and 3 introns has been identified.

Introns have 456, 1500, 224 and 524 pairs of nucleotides respectively.

Exons have 2300, 500 and 4600 pairs of nucleotides respectively.

When performing a Northern Blot with a RNA probe for this gene in a human cellular extract,a pattern with 3 bands was observed in the autoradiography:

Each band corresponds to RNAm molecules of the following sizes: approximately 2700 pairs of nucleotides, 1200 pairs of nucleotides

and 1000 pairs of nucleotides. Explain the results of the Northern Blot.

Extra question: what would you do to improve the analysis?

Key Concepts: transcription, splicing, alternative splicing.

Thank you very much!!

-mj711-

hints:

you have your introns and exons labelled in reverse.

mrna is produced from combinations of exons (alternative splicing).

the sizes of product are approximations (not exact).

-mdfenko-

Thank you! The number of nucleotides in the introns is irrelevant, isn't it?

-mj711-

pretty much (at least, for your purpose)

-mdfenko-