Let’s compute the number of 21-rung models it would take to represent (a) a single gene,* (b) a complete chromosome, or even (c) a whole genome, including the largest one of all, Polychaos dubium, belonging to a genetically bloated amoeba. The genes here are well- studied. TP53, the human tumor suppressor gene, is in fact the most thoroughly studied gene of all.
To do the calculation, just divide the number of rungs/nucleotide pairs by 21, to compute the number of models. Then, to visualize this number of models, in their total length, just take the number of models and turn that into linear feet by multiplying the number of models by three (3) feet—the length of each model. For longer results, you can then divide the “total length in feet” by 5,280 for the number of miles.
How many of our DNA models would be required for…
A. TP53 Gene: 1179 rungs/nucleotide pairs – would require ____ models
Length in feet: _______
B. Cytochrome C Gene: 312 rungs/nucleotide pairs – would require ____ models
Length in feet: _______
C. Human Y Sex Chromosome: 58 million rungs/nucleotide pairs – would require ___________ models.
This would have this length in feet: _________ and miles:_________
D. Human X Sex Chromosome: 156 million rungs/nucleotide pairs – would require ___________ models.
This would have a length in feet of __________ and this length in miles:__________.
E. Rose genome: 560 million rungs/nucleotide pairs – would require _____________ models.
This would have a length in feet of __________ and this length in miles:__________
F. Dog genome: 5 billion rungs/nucleotide pairs – would require _____________ models.
This would have a length in feet of __________ and this length in miles:__________
G. Amoeba genome (Polychaos dubium): 670 billion rungs/nucleotide pairs – would require ___________ models.
This would have a length in feet of__________ and this length in miles:__________
* The figure of gene length given here is the mRNA length or “spliced version” of the gene
information, after all intron commercial breaks have been removed. Later lessons will explain
this process.
