When the genomes of various organisms are compared, why is the genome size not directly correlated with gene number?
What will be an ideal response?
Ans: Organisms differ in the amount of repetitive DNA they contain, how many members there are in gene families, the size and number of introns, and whether the whole genome has undergone a duplication. Prokaryotes and unicellular/oligocellular eukaryotes have more unique DNA, whereas multicellular eukaryotes have more repetitive DNA and larger gene families. Genome duplications are prevalent in plants, where first the genome became tetraploid and then the duplicated genes diverged resulting in a doubling of the genome size.
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