Genetics and molecular biology
Could Humans Have Another Chromosome?
Artificial chromosomes are real, they work in cells, and they are nowhere near what the Kings program claims to have built.
Plausible ExtrapolationWhat we actually know
Humans carry 23 pairs of chromosomes. Extra copies of existing chromosomes usually cause serious developmental consequences. But researchers have built human artificial chromosomes — engineered pieces of DNA with the three parts a chromosome needs to survive cell division: a centromere, telomeres at both ends, and origins of replication. In laboratory cells, these can carry added genes and be inherited through division.
Where the extrapolation begins
Scaling a laboratory artificial chromosome up to a whole organism, carried in every cell from conception and passed reliably through development, is an enormous jump — but it is a jump in engineering, not in principle. The story treats the added chromosome as the delivery method for everything CROWN designed, which keeps the modifications separate from the natural genome.
What the novel invents
The fiction begins with reliability. In the book the added chromosome behaves perfectly across an entire body and an entire lifetime. Real artificial chromosomes are lost from cells, silenced, or rearranged. CROWN's version does not fail, and the book does not fully explain why.
Questions to think about
- — Why might engineers prefer to add a chromosome rather than edit existing ones?
- — If a trait lives on an added chromosome, is it 'yours'?
Where to read next
- — Reviews on human artificial chromosomes (HACs) in gene-therapy literature
- — Basic chromosome structure: centromeres, telomeres, replication origins
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