Human Gene Count Slashed

jd writes "The estimate for the number of genes in human genetic code has been savagely revised downwards. The new estimate, of between 20,000 to 25,000 genes is marginally less than the 27,000 for the Arabidopsis, a flowering plant in the mustard family. Earlier estimates had placed the number of genes at around 44,000 - or even as high as 100,000. Eric Lander of the Broad Institute in Cambridge, Massachusetts is quoted in the CNN story as saying that the number of genes isn't as crucial as how they are used." Read on for more, below.

jd continues: "This has the potential for making life extremely interesting for genetic engineers, given that both individual genes and interactions between genes must be proportionately more complex, in order to get the same level of complexity out. Half the number of genes equates to twice the information encoded in forms other than discrete physical blocks of code.

There is no mention in the article of a story running in 2002 of genetic therapies unexpectedly causing cancer, although if you now factor in the increased complexity of interactions, it is possible that such side-effects can be better understood and therefore prevented. The new estimates, therefore, are more than just idle curiosity but have the potential for impacting how the science is approached."

Comments

Re:Complexity for smaller?

[PhrostyMcByte]

I think a good analogy for the /. croud would be ASM and C. ASM has a very small set of instructions and can be very complex to piece together. C has a much larger set and it is relatively easy to use.

Re:genes, not genomes

[Anonymous Coward]

This is particularly interesting because with less genes then there are less genes that can interact with each other (I'm not talking about major/minor genes). As scientists are learning, the inhibition and activation of genes is alot more complicated than expected. With less genes, it means that the methods such as histone inhibition or non-genetic micro-RNA are more significant. Of course, it may also mean that DNA isn't the holy grail of biology, like we all thought (instead it is a complex interaction between micro-RNA and DNA).

Not only that...

[FiReaNGeL]

According to scientists, we gained 1000 genes compared to rodents when we diverged from them 75 millions years ago. And we 'lost' 33 genes compared to them (they have a functional copy, we have a nonfunctional pseudogene; it's still there, only not working - stop codons, etc).

The "we must have more gene than (insert stupid animal or plant here)" is funny. Our superiority complex at its best.

Read about the whole thing (with more links) on my blog (see sig)

Does it really matter?

[Tezkah]

I was at a lecture by Evelyn Fox Keller, and she said that there has been a paradigm shift and we're moving from breaking up biology into tiny parts, to seeing the whole picture. Whether theres 100,000 or 20,000 genomes seems rather trivial.

Re:The Scariest Part of the Article...

[larley]

Well, technically, you CAN buy genes. There are quite a few companies that sell pre-sequenced genes. In fact, the entire genomes of several organisms are available in varying amounts ligated into Bacterial Artificial Chromosomes (BACs) and plasmids. An interesting link is http://www.arabidopsis.org/ - There's a lot of information on Arabidopsis, where they keep a database of the entire Arabidopsis genome as well as many freely-available tools for its analysis.

Re:Ah

[anonymous cowherd (m]

Note that even with "only" 20K genes, this still gives us nearly 400M subsets of 2 individual genes to ponder. The complexity of the human organism is not surprising. In fact, it would be surprising if it were not so complex.

Re:Complexity for smaller?

[metlin]

I'm not sure how that is.

"We just have to get used to the fact that we don't have many more genes than a worm," Rubin said.

So how can humans be so complex with relatively few genes?

Seems to me like the instruction sets are the same, while the coding complexity varies?

Re:Ah

[kilonad]

And if we were to consider the possiblity of up to every gene interacting with each other, that would give us 20000!, or roughly 1.819e+77337 possibilities. (surprisingly enough, that didn't crash the windows calculator program, although it did take a second or two even on an A64)

Genes -- Proteins

[oddwick11]

An often unknown fact is that a single gene can code for thousands of different proteins. Protein regulation can occur in a variety of way, one of which is through "junk" DNA.

Currently little is known on the exact mechanism, which is a huge impediment to proteomics. As the phenomenon is elucidated, expect to see a lot more useful information coming out of genome projects.

Computationally predicting the 3-D structure and function of a gene is far more important than you probably realize. Reaching this point will revolutionize almost every aspect of your life, from pharmaceuticals, to nutrition, to silico-neural interfaces.

Re:genes, not genomes

[delco]

DNA isn't the holy grail of biology, like we all thought (instead it is a complex interaction between micro-RNA and DNA).

Interesting. I'd go out on a limb and say it was the process of translation or even protein folding that is the actual holy grail.

There are some camps that believe that the DNA->mRNA interaction (aka transcription) is less complex and more predictable than the mRNA->Protein interaction (aka translation). If my memory serves me well, the process of transcription usually produces a fairly good "copy" of the DNA sequence, while translation seems to have a few unknowns in how he sequence is transformed into AA chains. And then the way in which the proteins fold, and hence gain their function is still up for grabs.

Re:Complexity for smaller?

[avsed]

Actually, that's a bad analogy, since modern assembly possesses a significantly richer grammar than C. However, it is correct to say that the interactions between language elements (instructions) in ASM are very much simpler than in C.
More on topic: Why are people surprised that millions of years of evolution has resulted in a high entropy encoding "format" (the genome) whose consituent elements are multipurpose and have complex interactions with each other? An animal is more evolved (has a history of more complex environmental interactions) than a plant, so why shouldn't its genome be less redundant / contain more entropy? Comparisons of number of genes are (to return to the computing analogy) like comparing two processors based on their physical size.
D.

Re:Genomes?

[pyrosoft]

J. Craig Venter himself, apparently.

Frogs

[FuzzyDaddy]

Gene count is a funny thing. Frogs, for example, have a lot of genes to guide their development from egg to tadpole to account for variations in water temperature and chemistry. Mammals gestate in a much more controlled environment (controlled temperature and chemistry), and hence do not need this huge complex of genes.