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Scientists Analyze Chromosomes 2 and 4: Discover Largest "Gene Deserts"
National Human Genome Research Institute ^ | 06 April 2005 | Staff

Posted on 04/13/2005 6:20:23 PM PDT by PatrickHenry

A detailed analysis of chromosomes 2 and 4 has detected the largest "gene deserts" known in the human genome and uncovered more evidence that human chromosome 2 arose from the fusion of two ancestral ape chromosomes, researchers supported by the National Human Genome Research Institute (NHGRI), part of the National Institutes of Health (NIH), reported today.

In a study published in the April 7 issue of the journal Nature, a multi-institution team, led by [load of names deleted, but available in the original article].

"This analysis is an impressive achievement that will deepen our understanding of the human genome and speed the discovery of genes related to human health and disease. In addition, these findings provide exciting new insights into the structure and evolution of mammalian genomes," said Francis S. Collins, M.D., Ph.D., director of NHGRI, which led the U.S. component of the Human Genome Project along with the DOE.

Chromosome 4 has long been of interest to the medical community because it holds the gene for Huntington's disease, polycystic kidney disease, a form of muscular dystrophy and a variety of other inherited disorders. Chromosome 2 is noteworthy for being the second largest human chromosome, trailing only chromosome 1 in size. It is also home to the gene with the longest known, protein-coding sequence - a 280,000 base pair gene that codes for a muscle protein, called titin, which is 33,000 amino acids long.

One of the central goals of the effort to analyze the human genome is the identification of all genes, which are generally defined as stretches of DNA that code for particular proteins. The new analysis confirmed the existence of 1,346 protein-coding genes on chromosome 2 and 796 protein-coding genes on chromosome 4.

As part of their examination of chromosome 4, the researchers found what are believed to be the largest "gene deserts" yet discovered in the human genome sequence. These regions of the genome are called gene deserts because they are devoid of any protein-coding genes. However, researchers suspect such regions are important to human biology because they have been conserved throughout the evolution of mammals and birds, and work is now underway to figure out their exact functions.

Humans have 23 pairs of chromosomes - one less pair than chimpanzees, gorillas, orangutans and other great apes. For more than two decades, researchers have thought human chromosome 2 was produced as the result of the fusion of two mid-sized ape chromosomes and a Seattle group located the fusion site in 2002.

In the latest analysis, researchers searched the chromosome's DNA sequence for the relics of the center (centromere) of the ape chromosome that was inactivated upon fusion with the other ape chromosome. They subsequently identified a 36,000 base pair stretch of DNA sequence that likely marks the precise location of the inactived centromere. That tract is characterized by a type of DNA duplication, known as alpha satellite repeats, that is a hallmark of centromeres. In addition, the tract is flanked by an unusual abundance of another type of DNA duplication, called a segmental duplication.

"These data raise the possibility of a new tool for studying genome evolution. We may be able to find other chromosomes that have disappeared over the course of time by searching other mammals' DNA for similar patterns of duplication," said Richard K. Wilson, Ph.D., director of the Washington University School of Medicine's Genome Sequencing Center and senior author of the study.

In another intriguing finding, the researchers identified a messenger RNA (mRNA) transcript from a gene on chromosome 2 that possibly may produce a protein unique to humans and chimps. Scientists have tentative evidence that the gene may be used to make a protein in the brain and the testes. The team also identified "hypervariable" regions in which genes contain variations that may lead to the production of altered proteins unique to humans. The functions of the altered proteins are not known, and researchers emphasized that their findings still require "cautious evaluation."

In October 2004, the International Human Genome Sequencing Consortium published its scientific description of the finished human genome sequence in Nature. Detailed annotations and analyses have already been published for chromosomes 5, 6, 7, 9, 10, 13, 14, 16, 19, 20, 21, 22, X and Y. Publications describing the remaining chromosomes are forthcoming.

The sequence of chromosomes 2 and 4, as well as the rest of the human genome sequence, can be accessed through the following public databases: GenBank (www.ncbi.nih.gov/Genbank) at NIH's National Center for Biotechnology Information (NCBI); the UCSC Genome Browser (www.genome.ucsc.edu) at the University of California at Santa Cruz; the Ensembl Genome Browser (www.ensembl.org) at the Wellcome Trust Sanger Institute and the EMBL-European Bioinformatics Institute; the DNA Data Bank of Japan (www.ddbj.nig.ac.jp); and EMBL-Bank (www.ebi.ac.uk/embl/index.html) at EMBL's Nucleotide Sequence Database. [Links in original article.]

NHGRI is one of the 27 institutes and centers at NIH, an agency of the Department of Health and Human Services. The NHGRI Division of Extramural Research supports grants for research and for training and career development at sites nationwide. Additional information about NHGRI can be found at www.genome.gov.


TOPICS: Culture/Society; Miscellaneous; Philosophy
KEYWORDS: chromosomes; crevolist; dna; evolution; genetics
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To: Dog Gone

Think of a taking a trip to the grocery store with a friend. If you come out with more bags than your friend, that doesn't necessarily mean you bought more groceries. Similarly having more chromosomes (analogous to more bags) doesn't necessarily imply having more genes (analogous to the groceries.) Of course, having said that, having more genes in a genome is also not necessarily required to have more complexity.


181 posted on 04/14/2005 5:35:29 AM PDT by stremba
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To: Cicero

If we were created by God, then what possible observation would be different from what we would observe if we are the result of evolution? If both ideas produce identical observable results, the science will assume the simpler one. The ideas boil down to: We see certain observations. We can account for these observations by well understood natural processes or we can account for them by well understood natural processes and, in addition, an omnipotent supernatural being. Simpler, in a scientific sense, means we should not needlessly add entities to a theory. In this case, if we don't need God to account for observations, then a scientific theory should not include God. This doesn't mean that the theory says that God doesn't exist, but rather that God is not needed to explain the phenomenon that the theory tries to explain. I would contend that there is no difference in the observations that would be expected if God really created everything than there are if it's all a result of natural processes. If I am wrong, then please give a specific difference in what would be observed ONLY if God created everything, and not otherwise.


182 posted on 04/14/2005 5:43:07 AM PDT by stremba
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To: Echo Talon

It would help your credibility if you could actually state what evolution really says and not some cartoon version of it. Knocking down strawmen does nothing to help the Creationist's arguments.


183 posted on 04/14/2005 5:48:14 AM PDT by stremba
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To: Strategerist; Echo Talon

I also think that millions of Catholics will find it surprising to find out that the all-knowing authority, freeper Echo Talon, has pronounced that the Pope and any Catholics who believed him when he said that evolution is not incompatible with Catholicism are not really Christians!


184 posted on 04/14/2005 5:52:01 AM PDT by stremba
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To: Echo Talon

What the Pope states is exactly what you deny, namely that it is possible to be a Christian who believes that evolution is a valid scientific theory.


185 posted on 04/14/2005 5:56:45 AM PDT by stremba
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To: Thinkin' Gal
That makes more sense than some of the stuff from the simian side.
186 posted on 04/14/2005 6:10:00 AM PDT by Dataman
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To: PatrickHenry
"gene desert"?

More unused DNA?

Ofcourse you realize this proves me right.

187 posted on 04/14/2005 6:11:30 AM PDT by biblewonk (Jer 7:18 and the women knead dough, to make cakes for the queen of heaven;)
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To: furball4paws; jwalsh07

dang I can be a dope sometimes. An hour later I was lying in bad going..... haploid, haploid.... chromosomes.... increased harvest.... big tomatoes..... ahhhhhhh


188 posted on 04/14/2005 6:16:44 AM PDT by ndt
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To: Vaquero
"Species" not "specie"; the words do have different meanings.

(I may often didact but I never pedant.)
189 posted on 04/14/2005 6:17:54 AM PDT by Doctor Stochastic (Vegetabilisch = chaotisch is der Charakter der Modernen. - Friedrich Schlegel)
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To: hershey
... Well, it looks as if the Good Lord has a plan for us. He's left room to add stuff as needed. It's like soup. A little seasoning, then taste to see what's missing...and add that.

"Look at your children
See their faces in golden rays
Don’t kid yourself they belong to you
They’re the start of a coming race
The earth is a bitch
We’ve finished our news
Homo sapiens have outgrown their use
All the strangers came today
And it looks as though they’re here to stay"

"Oh you pretty things (oh you pretty things)
Don’t you know you’re driving your
Mamas and papas insane
Oh you pretty things (oh you pretty things)
Don’t you know you’re driving your
Mamas and papas insane
Let me make it plain
You gotta make way for the Homo superior"

190 posted on 04/14/2005 6:22:39 AM PDT by dread78645 (Sarcasm tags are for wusses.)
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To: Doctor Stochastic

guess I created my own singular.


191 posted on 04/14/2005 6:31:25 AM PDT by Vaquero ("There is nothing lower than the human race - except the french." (Mark Twain))
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To: Echo Talon

The point is, that according to creationism there is a wide gap between humans and apes. According to creationism, if I show you a creature, it should be no problem for you to tell me if it's an ape or a human. The point is that CREATIONISTS disagree as to whether these creatures are apes or humans, thus falsifying the idea that there should be no problem distinguishing apes from humans.


192 posted on 04/14/2005 6:31:30 AM PDT by stremba
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To: Thinkin' Gal
Chromosome 2:


193 posted on 04/14/2005 6:41:24 AM PDT by Lijahsbubbe (Expedients are for the hour, but principles are for the ages.)
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The universe-builds-a-bigger-idiot placemarker.


194 posted on 04/14/2005 6:46:16 AM PDT by balrog666 (A myth by any other name is still inane.)
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To: Chiapet
De-lurking briefly to say that you reckon correctly.

Why thank you! It's always nice to have one's prejudices confirmed.

195 posted on 04/14/2005 6:55:32 AM PDT by Thatcherite (Conservative and Biblical Literalist are not synonymous)
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To: jwalsh07
How do you supppose that first 23 Chromosomer haploid felt when he met his female counterpart, the 24 Chromosomer haploid?

Don't know about the first, but this situation is not extremely rare in humans. Most mismatches are detrimental, but a few go unnoticed unless a DNA test is done.

196 posted on 04/14/2005 6:56:47 AM PDT by js1138 (There are 10 kinds of people: those who read binary, and those who don't.)
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To: Echo Talon
Sorry, but im tired and can't keep you heathens entertained anymore... I have been up all night working on a project. My advise to you is... Run to church!!! Don't walk.. RUN TO CHURCH! :P

Are there heathens here? Where? How do you know?

197 posted on 04/14/2005 7:12:43 AM PDT by Thatcherite (Conservative and Biblical Literalist are not synonymous)
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To: stremba
... having said that, having more genes in a genome is also not necessarily required to have more complexity.

More code doesn't necessarily make a better program.

198 posted on 04/14/2005 7:36:52 AM PDT by js1138 (There are 10 kinds of people: those who read binary, and those who don't.)
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To: Doctor Stochastic

Bad spelling drives out the good.


199 posted on 04/14/2005 7:39:38 AM PDT by js1138 (There are 10 kinds of people: those who read binary, and those who don't.)
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To: jwalsh07
Dunno.

This is the usual answer that comes from basic ID theory. It's no surprise that most folks don't have much use for it.

200 posted on 04/14/2005 7:42:23 AM PDT by <1/1,000,000th%
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