80 megabytes seems too small to specify a human
|June 21, 2014||Posted by scordova under 'Junk DNA'|
and Larry Moran argue that most of the human genome of 3.2 giga base pairs is junk. I will appeal to engineering intuition and say these guys are awfully premature in their pronouncements since their estimates would imply that a mere 80 megabytes would be enough specify not only an adult human but all the developmental forms that have to be implemented along the way from conception to adulthood.
Where did I get the 80 megabyte number? The human genome is about 3.2 giga base pairs. Evolutionnews reports Graur is arguing 5% to 15% of the human genome is functional. For simplicity I’ll suggest the mid range figure from Graur as 10%. That means then 3.2 billion * 10% = 320 million base pairs. Since each nucleotide from one strand associated with a base pair has 2 Shannon bits, that’s 320 x 2 = 640 million bits. There are 8 bits in a byte so 640,000,000 / 8 = 80 megabytes.
From the BioMumbers website, human cells are reported to have on the order of 1 to 10 billion physical proteins from a supposed set of only 20,000 coding genes. If a human has 1 billion physical proteins per cell and there are 200 trillion cells in a grown human, that implies coordination of 200 billion trillion proteins. 😯
Do you think 80 megabytes could provide enough information to assemble and manage not only 200 billion trillion proteins, but all the developmental forms along the way? If you were tasked to build something as fearfully and wonderfully made as a human with its complex systems (nervous, immune, digestive, optical, auditory, endocrine, respiratory, smell sensing, vascular, reproductive, skeletal, urinary, lymphatic, muscular, etc.), would you feel comfortable having only 80 megabytes to store all the construction information for an adult plus all the developmental forms? Not me, and not a lot reasonable people either.
In fact, 3.2 giga bases (or 800 megabytes) would even seem too small. My computer RAM has more than 800 megabytes, and even that doesn’t seem like it would be enough. For those reasons, I think DNA cannot possibly contain all the heritable information that is important to humans. For DNA to work for a human, it must presuppose information rich parts in the rest of the cell. I think there is a lot of heritable information outside of the DNA, and we’re just not doing the information accounting properly. Epigenetic information needs to be accounted for.
Without ribosomes, spliceosomes and host of other pre-existing machines, the DNA would be useless, so I suppose there is information implicit outside the genome which had to be specified even though it is not explicit. For example a compressed ZIP file presupposes a decoder to decompress it. That decoder has a certain amount of information associated with it.
If I were a designer and had only 800 megabytes of DNA to specify something as complex as a human, I would think I’d have to store lots of assembly instructions outside the DNA and implement some of the manufacturing process instructions outside of the DNA. If some of the manufacturing process instructions are implicitly stored outside of DNA, then that is yet more information we have to account for, and if we include that, I think it strains credulity that a mindless process could construct something as complex as a human.
Added to this, the human has moderate self-healing capabilities. How can you construct a system as complex as a healthy human with the added ability to self heal certain parts? I think Dan Gruar’s 80 megabyte argument is on shaky ground, unless he wants to argue for large amounts of epigenetic information. But arguing for large amounts of epigenetic information doesn’t exactly help his crusade against functionality.
He is quite confident he is right because he places his faith in evolutionism more than in reasonable engineering intuitions.
1. photo credits Evolution News