Module 4

Last update by mayur on 03/31/2014
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The full-length (i.e., containing the entire protein coding region) cDNA for a specific eukaryotic gene in humans is 1500 nucleotides long. You screen a pig genomic library with this cDNA and isolate two genomic clones of different lengths. Both clones are sequenced and found to be 1900 and 2100 nucleotides long from start codon to stop codon. How would you explain the presence of two genomic clones in pigs, and the discrepancies in their length compared to the cDNA probe?

Answer:

This gene was most likely present in a common ancestor, the presence of two copies could be from gene duplication and the increase in length could be due to elongation of repeats included in the sequence.

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