Each sperm has 37.5 Mb of DNA, an ejaculation means transferring 15,875 GB in about 3 seconds

Each sperm has 37.5 Mb of DNA, an ejaculation means transferring 15,875 GB in about 3 seconds

In an episode of the BBC program QI – Quite Interesting, as you can see below in video the great Stephen Fry asks : How much information do you think there is in the DNA of a small sperm …?

And he answers: it is 37.5 MB. In a normal male ejaculation, it is equivalent to 15,875 GB. That’s roughly 7,500 information laptops. However, are your figures correct? Maybe it fell short.

More information than expected

The Twitter account summarizes Fry’s claims like this:

  • Sperm has 37.5 MB of DNA information.
  • One ejaculation transfers 15,875 GB of data, equivalent to 7,500 laptops.

But maybe the numbers should be higher if we calculate what Wikipedia says . The haploid human genome (23 chromosomes) is approximately 3 billion base pairs long and contains about 30,000 genes. Since each base pair can be encoded by 2 bits, we have about 750 megabytes of data .

A single somatic (diploid) cell contains twice this amount, or about 6 billion base pairs.

Men have less than women because the Y chromosome is about 57 million base pairs, while the X is about 156 million, but in terms of information, men have more because the second X contains almost the same information. than the first . Since individual genomes vary in sequence by less than 1% from each other, variations of a given human genome from a common reference can be losslessly compressed to approximately 4 megabytes .

The entropy rate of the genome differs significantly between coding and non-coding sequences . It is close to the maximum of 2 bits per base pair for coding sequences (approximately 45 million base pairs), but less for non-coding parts. It varies between 1.5 and 1.9 bits per base pair for the individual chromosome, with the exception of the Y chromosome, which has an entropy rate of less than 0.9 bits per base pair .

So it’s actually over 30,000 TB of DNA-encoded information if your sperm count isn’t low . This means that the egg withstands this DDoS attack at 1.5 terabytes per second, and only lets through one packet of data, making it the best firewall in the world! The downside is that this one small data packet that it lets through locks up the system for 9 months.