Genome Surprise

Catskul writes "Along with the news that the polished and (more nearly) complete human genome being published Monday, comes a surprising observation about the genome: We have substantially fewer genes than expected; between 27,000 and 40,000 as compared to an original estimate of 140,000." Update: 04/14 01:22 GMT by T : For everyone who can't look at a Z, headline updated with an S in "surprise."

Comments

Not a new observation

[zach_smith]

Along with the news... comes a suprising observation about the genome: We have substantially fewer genes than expected

This observation was already made a couple of years back when the first draft was published. Note the date on the second link.

Re:Just for comparison's sake...

[Pharmboy]

That's nothing new, though - scientists have known a long time there's no scientific basis for the concept of "race" as applied to humans. It's a cultural construct.

Not to argue with your basic idea there, but how does culture determine the similarities then? The fact that most native Africans have dark skin, most Northern Europeans are relatively fair skinned, and most Asians are notably shorter than Native Americans? There has to be some genes doing something. Or some other mechanism we have yet to discover.

Our perception of 'race' is surely more exaggerated than the actual genetic differences alone justify, but race is more than genes. For instance: dictionary.com defines race as:

* A local geographic or global human population distinguished as a more or less distinct group by genetically transmitted physical characteristics.

* A group of people united or classified together on the basis of common history, nationality, or geographic distribution: the German race.

* A genealogical line; a lineage.

* Humans considered as a group.

So race is neither purely genetic, nor purely cultural. We forget that sometimes.

Background Info

[Acidic_Diarrhea]

Want To Know What The Human Genome Project Is?

Begun formally in 1990, the U.S. Human Genome Project is a 13-year effort coordinated by the U.S. Department of Energy and the National Institutes of Health. The project originally was planned to last 15 years, but rapid technological advances have accelerated the expected completion date to 2003. Project goals are to

• identify all the approximate 30,000 genes in human DNA,
• determine the sequences of the 3 billion chemical base pairs that make up human DNA,
• store this information in databases,
• improve tools for data analysis,
• transfer related technologies to the private sector, and
• address the ethical, legal, and social issues (ELSI) that may arise from the project.

To help achieve these goals, researchers also are studying the genetic makeup of several nonhuman organisms. These include the common human gut bacterium Escherichia coli, the fruit fly, and the laboratory mouse.

A unique aspect of the U.S. Human Genome Project is that it is the first large scientific undertaking to address the ELSI implications that may arise from the project.

Another important feature of the project is the federal government's long-standing dedication to the transfer of technology to the private sector. By licensing technologies to private companies and awarding grants for innovative research, the project is catalyzing the multibillion-dollar U.S. biotechnology industry and fostering the development of new medical applications.

Sequence and Analysis of the human genome working draft was published in February, 2001, in Nature and Science. See an index of these papers and learn more about the insights gained from them.

For more background information on the U.S. Human Genome Project, see the following

• HGP Goals (1998-2003)
• HGP Progress
• HGP History
• Human Genome News

What's a genome? And why is it important?

• A genome is all the DNA in an organism, including its genes. Genes carry information for making all the proteins required by all organisms. These proteins determine, among other things, how the organism looks, how well its body metabolizes food or fights infection, and sometimes even how it behaves.
• DNA is made up of four similar chemicals (called bases and abbreviated A, T, C, and G) that are repeated millions or billions of times throughout a genome. The human genome, for example, has 3 billion pairs of bases.
• The particular order of As, Ts, Cs, and Gs is extremely important. The order underlies all of life's diversity, even dictating whether an organism is human or another species such as yeast, rice, or fruit fly, all of which have their own genomes and are themselves the focus of genome projects. Because all organisms are related through similarities in DNA sequences, insights gained from nonhuman genomes often lead to new knowledge about human biology.

  To understand more read

  • The Science Behind the Human Genome Project: Understanding the Basics

Re:I thought so.

[JDevers]

Actually no, still wrong. A genome is the entire complement of genes an organism possess, a chromosome is a relatively arbitrary unit in which the genome is broken into. I doubt any scientist ever suggested that "more chromosomes=more complex" seeing as how most higher plants have significantly more chromosomes than any animals. A gene on the other hand is a functional unit, it can code for one or more proteins but they have a well known beginning and end (both to us and to the transcription machinery). These three words are about as non-exchangable as three words can be. You noted you weren't "intending to be scientific", however you were commenting on a somewhat scientific article in a moderately well-read community. If you don't want anyone to insult you, don't comment on things you don't understand.

The Real Human Genome Project

[Mars Ultor]

While I'm certainly not a learned expert, as a new graduate of an Honours Genetics program in Canada, I feel I must point out a few misconceptions found in the story intro.

I let out an audible groan over the 'revelation' that the human genome contains at most 40,000 genes, compared to the original estimate of ~150,000. I was relieved when I noticed that the article linked to dated to 2001. This makes sense, since that discrepancy was first discussed during my courses over two years ago.

The other grain of salt that needs to taken is the idea of a "completed" genome. The human genome is nearly sequenced, however it the annotation of the genome that matters most. To place this into context, the genome of the fruit fly, Drosophila melanogaster, is over 75% annotated. Currently only a small portion of the human genome is annotated, that is to say, the roads are mapped, and the streets (or in this case, genes) are identified and their function characterized. This is one of the most essential tasks still facing biologists today. Without knowing all the potential genes, as well as their function and expression patterns, the human genome is no better a guide than using a globe to navigate the streets of Toronto (or New York, take your pick).

As it has been mentioned before, I won't delve too far into the fact that a given stretch of DNA can code for genes in two different directions, and in three different "frames" per direction. On top of this, the mRNA produced from the DNA can be spliced in numerous ways. A single expanse of DNA can produce countless different proteins - and its proteins, not genes, that carry out all the functions our body needs to survive.

Humans are extremely complex, but as we go about our 'very' important lives, it's humbling to know that on the surface, we do not contain many more genes than some other 'lesser' forms of life on this planet.

Re:I thought so.

[evilquaker]

The low number of genes means humans have as few as 300 more genes than a mouse and only twice the genes of the fruit fly. "A lot of people will find that philosophically disturbing," says theoretical biologist Jean-Michel Claverie

I don't see why they should. More genes == more superiority? Who made up that rule?

The brightest minds of biology did, over 10 years ago... and so the central dogma of biology ("one gene => one protein => one function") was taught to a generation of students.

Of course, this completely misses two of the biggest results in the last few years: the acknowledgment of alternative splicing as a common phenomenon (10 years ago, people thought it happened in 5% of human genes, now we know it's more like 50%) and the identification of miRNAs as regulators of gene function.

But it's so hard to argue with dogma...

genomics is only the first step

[EngMedic]

remember, folks.. just because we have a genetic sequence is about 10% of the story. Proteomics is the next big thing, and there are a lot more protiens than genes.

Re:I thought so.

[kmellis]

People are trying to explain this in different ways, but let's make it clear and simple:

The modern concept of race is that groups of people that are readily identifiable via a few physical traits (primarily skin color, but also face and eye shape, height, etc.) are more closely genetically related, on average, to each other than to they are to other groups.

This has been proven to be false.

It doesn't have to be false. Populations do diverge genetically, that's certain. And human populations could have diverged in ways that are expressed uniquely as gross anatomical differences. But they haven't.

A key word in that previous paragraph is "uniquely". You see, for something like skin color to be a reliable indicator of genetic relatedness, the skin color has to have a one-to-one correspondence with the genetic variation that causes it.[1] For example, I happen to have a rare genetic disease that is a mutation on the gene that controls collagen. As far as anyone knows, this mutation exists only among a few people in the world that have a common ancestor. So if you find this mutation, then you've found someone related to me. Put another way, if you find someone with the disease I have, they're related to me.

In contrast, there are other mutations on the collagen gene that exist among many unrelated people. It's a common mutation. If you find someone with that corresponding disease, there's no guarantee that they're related to someone else with that disease.

Now, the problem is that all of the features that are associated with how people define "race" are like the latter example, not the former. That is, genetically unrelated people can have dark skin. Dark skin can and has arisen among unrelated populations. Worse, dark and light skin has arisen among relatively closely related populations such that a given light skinned population is more closely related to a given dark skinned population than it is to another light skinned population. So, looking at the human race as a whole, skin color is an unreliable indicator of genetic relatedness.

Within a population that is reasonably restricted, however, it can be a reliable indicator of relatedness. Almost all African Americans have a common ancestor from west Africa. But west Africans are not closely related to some other dark skinned Africans. So, for example, while African Americans share a tendency to having the gene that causes sickle cell anemia, other dark skinned people--including many other African peoples--do not.

The reason this is all very important is because the modern idea of race has been assumed to have been validated on the basis of genetics. Furthermore, since it's assumed that members of a "race" are closely related genetically, and since it's obviously true that genetically closely related individuals are likely to share a lot of traits, it's been assumed that members of a race share lots of similar traits. Thus, people have argued about gross differences between races in the matter of intelligence, athletic ability, temperment, what have you. And if race did reliably indicate genetic relatedness, then these assumptions might have some merit. But since race is not an indicator of genetic relatedness, it can't be (in this respect[2]) an indicator of similarity in these traits.

Since the whole modern notion of race rests upon this assumption of relatedness and shared traits, and that notion is false, this is why some people say that the concept of race is scientifically false. They're not saying that genetics is false, or that genes don't control the expression of the various features associated with race. They are saying that the particular kind of relationship imagined between genetics and race doesn't exist.

And, in the end, what you're left with is a very messy sociological conception of race which has everything to do with local cultural standards and nothing at all to do with genetics in a meaningful way.