The Genome At Ten: Two Pictures

In honor of the tenth anniversary of the human genome project, here are a couple telling images, courtesy of Mihaela Pertea and Steven L Salzberg.

First: a visual history of the estimates of the number of genes in the human genome.
gene number600And second, a warning to anyone who believes in an iron law that the more protein-coding genes in a species, the more sophisticated/complex/cool/human that species is:
gene count600
I for one welcome our grapey overlords.

[Update: Biochemist Larry Moran takes issue with the very high numbers for early gene number estimates. Steven Salzberg defends the graph. Read it all here!]

0 thoughts on “The Genome At Ten: Two Pictures

  1. Any reason why the comma is in the wrong place in “670,0000”?

    Also, who made that estimate before the genetic code was cracked? This was a guess at how much proteins we have?

  2. I never understand why folks expect vertebrates to have more genes than plants. Think of all the extra biochemistry plants have to do: assimilating inorganic nutrients and photosynthesizing. This is in addition to respiration, cell division, differentiation, etc. that we all do.

  3. The comma out of place was a typo inserted by the copy editors. We caught it and asked for them to fix it, but they didn’t catch it in time for the print version. I think it is now corrected in the online version.

    The estimate of 6.7 million genes is by F. Vogel. who published it in 1964, when the genetic code was only partially known. He basically took the estimated size of the genome in base pairs, then divided it by the length of the first gene to be decoded, hemoglobin, which is very short, only 450 bases. He didn’t know about introns, intergenic DNA, or anything of the sort, but it was a valiant effort.

  4. The reduction in the estimates of the number of protein-coding genes in the human genome parallels our increased understanding of the complexities involved in regulation of gene activity. For example, many types of non-coding RNAs have been described as well as their roles in modulating the information flow from DNA to protein.

    At the same time, I believe that the human genome’s reduced “tool kit” (in terms of number of protein-coding genes) shows a certain level of our genome’s sophistication. Think of the many different ways one can use a screwdriver – say to open a can of paint, or its handle as a hammer. In other words, different proteins can join to different networks in a tissue- or developmental-specific manner. In conjunction with this are the alternatively spliced mRNAs, which often lead to different protein isoforms (proteins that are mostly the same, but with perhaps one different functional subdomain). Think of a Phillips vs. regular screwdriver.

    Thus, fewer genes has not meant there are fewer protein isoforms nor less complex protein-protein or protein-small molecule interaction networks. To the contrary, there is an increased complexity and that is one reason it has been difficult to define all the players in a particular human affliction such as type 2 diabetes or cancer.

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