Question

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. Screening of genomic libraries of several other organisms reveals that all of them contain only one genomic clone -- pigs seem to be the exception to the rule here. What evolutionary events might have led to the presence of two genomic clones in pigs, and the discrepancies in their length compared to the cDNA probe

Answer 1

In pigs, this gene suffered duplication and then paralogous genes diverged by accumulating mutations during evolution

Step-by-step explanation:

Paralogous genes can be defined as evolutionarily related genes that emerged by duplication in a common ancestor of the two species being compared. Gene duplication is one of the most important mechanisms of genome evolution by which paralogous genes arise and acquire novel functions. After gene duplication, one of the two functional gene copies is prone to accumulate mutations because the organism has two genetic sequences to produce the same protein encoded by this gene. In consequence, it is expected that the cDNAs obtained from these genetic sequences show differences in nucleotide length.