So I was eating this apple.... And I got wondering. Its easy to find out what the nutritional content of a food is. Its carbohydrates, protein, salt, energy etc just takes a quick google search, or a look on the side of a packet. But what about that most essential of all molecules? The life defining, imperfect recorder of millions (nay billions) of years of evolving history, that thing makes me a me, a cat cat, and yes a Pink Lady apple, a Pink Lady apple? |
How much DNA????
That's what I want to know!
So off to google I went. In 2010 the apple genome was sequenced. - A total length of 742.3 million base pairs of DNA was found. Now when they sequence a genome, they always do a haploid genome - one set of chromosomes (in this case 17 chromosomes), but apples fruit are diploid - 2 sets of chromosomes - 34 (well some are triploid - 3 sets, but that's a whole other story and Pink Ladies are definitely diploid). So that's double the DNA in each cell. |
The distance from 1 base pair to the next is a nice small 0.34 nanometers or 0.34 billionths of a metre. - pretty small huh?
So in a single apple cell the length of DNA is
That's just crazy - surely not.
Yep there is,
AND THAT'S NOT ALL!
There are lots of apple cells in a single apple!
I measured my apple - it had a seven cm diameter (0.07m diameter), a 3.5 cm radius (0.035m).
It was pretty round.
So the volume of my apple is 4/3 x pi x 0.035 x 0.035 x 0.035 = 0.000179594 metres cubed
So the numbers of cells in my apple is 0.000179594 divided by 0.0000000000081812309 = 21,951,953 cells
so the total DNA in my apple is 0.504764 x 21,951,953 = 11080556 metres
or
11,000 kilometres!!!!!
(No wonder it tasted good)