Question

It has been recently determined that the gene for duchenne muscular dystrophy (dmd) is more than 2000 kb (kilobases) in length; however, the mrna produced by this gene is only about 14 kb long. what is a likely cause of this discrepancy

Answer 1

The likely cause of this discrepancy is the introns have been sliced out during mRNA processing.
In most organisms, the coding regions (exons) are interrupted by the non-coding regions (introns). During transcription, the entire gene is copied into the pre-mRNA, which includes exons and introns. During the process of RNA splicing or processing, the introns are removed and exons joined to form a contiguous coding sequence.