Considerations in eukaryotic chromosomes The enormous amount of dna in eukaryotic cells poses the following obstacles to cells. 1. Compaction- The length of the total DNA content of a human cell is nearly 3 meters, yet it must be packed into a nucleus about 10-5 m in diameter 2. Selective transcription-In a typical differentiated eukaryotic cell, only a small fraction of the DNA (5%-10%o)is ever transcribed. Many genes that do undergo transcription do so only in certain cell lines in particular tissues, and then often only under special circumstances. To maintain and regulate such complex programs of selective transcription, the accessibility of the dna to RNa Polymerases must be under strict controlConsiderations in eukaryotic chromosomes The enormous amount of DNA in eukaryotic cells poses the following obstacles to cells: 1. Compaction - The length of the total DNA content of a human cell is nearly 3 meters, yet it must be packed into a nucleus about 10-5 m in diameter. 2. Selective transcription - In a typical differentiated eukaryotic cell, only a small fraction of the DNA (5%-10%) is ever transcribed. Many genes that do undergo transcription do so only in certain cell lines in particular tissues, and then often only under special circumstances. To maintain and regulate such complex programs of selective transcription, the accessibility of the DNA to RNA Polymerases must be under strict control