homi vs. homi

From ScienceDaily: Humans And Chimpanzees Genetically More Similar Than One Yeast Variety Is To Another

Scientists at the University of Gothenburg in Sweden say that humans and chimps are more similar on that level than two yeast species in the same genus. (FYI, we're in the same family as chimps, Hominidae or the great apes.)

I do think it's pretty cool... I like chimps, at least theoretically, as I don't know if I've ever met them. But they're cute, and they seem smart and feisty, and except for the whole endangered-species thing, I sometimes think I'd rather be an ape than a human.

I think this is a crappy comparison, though. This article says that there is a 4% difference in genes between the two yeast species, Saccharomyces cerevisiae and S. paradoxus, and a 1% difference between chimps and humans.

So, S. cerevisiae has 12,156,677 base pairs. I couldn't find a figure for the other. But say it's the same amount. With a 4% difference, that means around 486,267 base pairs are out of order or replaced in some way.

Not such an exact number for humans; everything says "approximately 3 billion." We can go with that, though. No numbers for the chimps, either, but you should look at the wiki article because they are adorable. Anyway. A 1% difference in 3 billion genes is... 3 million.

I just think there is a slight difference between almost 500,000 and 3 million, no matter the percentages.

Ah, well, I'm not a geneticist or anything. Maybe it is deep and meaningful. It is pretty cool to read about the Chimpanzee genome project and look at the only really obvious difference: at some point, for us, the 2nd and 3rd chromosomes that the chimp and human lines shared fused into one larger chromosome, with the addition about 150,000 or so base pairs. And since according to that article I posted this morning, the human and chimp line underwent the burst of genetic duplication that is thought to be the basis of our "human-ness," chimps are like our extended family, and I'm not trying to make a taxonomy pun here. They're like our cousin. Maybe second cousin, once removed. Hey, I don't mind grooming, but I won't eat mites.

genetic "volcano"

From ScienceDaily: Did Burst Of Gene Duplication Set Stage For Human Evolution?

This is pretty crazy stuff. Around 10 million years ago, the common ancestor of chimpanzees and humans started undergoing gene duplication at a much faster rate than normal, while other mutations like a single nucleotide change became less prevalent.

Evan Eichler, a geneticist with the University of Washington says, "There's a big burst of activity that happens where genomes are suddenly rearranged and changed." Duplication slowed down after the chimp and human lines diverged. '"You might like to think that humans are special because we have more duplications than did earlier species," he says, "but that's not the case."'

Apparently, though, this crazy burst of duplication is what makes humans human. It "creat[ed] an instability that persists in the genome of modern humans and contributes to diseases like autism and schizophrenia. But that gene duplication also may be responsible for a genetic flexibility that has resulted in some uniquely human characteristics."

the wacky world of lyme

From ScienceDaily: Scientists Identify Potential Key To Lyme Disease

Researchers from UT Southwestern Medical Center have noted that the bacteria that causes Lyme disease, Borrelia burgdorfei, is especially dependent on getting manganese from its host to establish infection, as opposed to iron like most pathogens. They then identified the specific enzyme that captures manganese for the bacteria. When they engineered a strain of B. burgdorfei lacking that protein and introduced it to mice, the bacteria wasn't able to infect.

I don't know if I would find this interesting except that I had Lyme a few years ago. It's fairly common where I live. My father and one of my sisters had it, too. I missed the telltale "bull's-eye" rash and must have thought I had the flu if I ever had the fever and malaise; when I was diagnosed and treated it was all extreme fatigue, joint pain, headaches, "Lyme fog," depression, mild hallucinations, and alternating insomnia and hypersomnia. It's a crazy, crazy disease. I would kind of suggest, you know, not getting it.

just no genome compare and contrast essays, please

From ScienceDaily: New Computational Technique Allows Comparison Of Whole Genomes As Easily As Whole Books

Based on a word frequency technique used to compare and categorize texts, professor of chemistry at UC Berkley Sung-Hou Kim and a group of researchers have developed a method that allows the comparison of entire genomes of species. Up to this point, comparisons have only been done between exons, which are the sequences of DNA used by RNA to make proteins. They ran a comparison of 518 genomes; six were eukaryotes, two random, and the rest bacteria and archaea. The tool, the feature frequency profile (FFP) method, easily separated the examples into domains and fairly reliably into phyla and classes, "with some interesting discrepancies compared to the currently accepted groupings." Interestingly enough, "most" of those discrepancies involved species whose classifications are in dispute.

This sounds pretty amazing. Dr. Kim gives many fields where this method will help, but I think learning more about how species relate with each other is the most interesting thing. Previously I posted an article about how Darwin's Tree of Life doesn't really tell the whole story of evolution and the development of life. I can't wait to see what kind of awesome things they discover.

RNA is bi....directional?

From ScienceDaily: Rewrite the Textbooks: Transcription is Bidirectional

Scientists at the European Molecular Biology Lab in Germany have discovered that RNA transcription of DNA is bidirectional from promoters, as opposed to all transcription happening in one direction. DNA is still pretty mysterious, so even though this isn't as incredibly exciting as naked singularities or quantum communication, it's still good to know. Also, I can impress my biology professor. I like doing that.

a web, note a tree

From New Scientist: Why Darwin was wrong about the tree of life

Growing evidence is showing Darwin's idea of life as a growing, branching tree is too simple by spades, mostly because of RNA and DNA research. This article goes into detail about endosymbiosis and the development of eukaryotic cells, horizontal gene transfer, viable hybrids, and DNA implantation by viruses. There's even the discussion of the possibility that animals with distinct and completely different larvae and adult stages could be the descendants of two very different species. Very interesting.

one for the other

From ScienceDaily: Mothers Pass On Disease Clues To Offspring

Apparently in many species, when females are pregnant and they might get ill, they produce less aggressive male offspring with a better immune system, and "[t]he results of this new study support the existence of a ‘trade off’ between social dominance and disease resistance."

Ha! So see, my desire for a less aggressive mate makes sense. Better disease resistance to pass down. Fuck social dominance, those assholes.

type 1 diabetes + celiac disease = bff

From ScienceDaily: Type 1 Diabetes And Celiac Disease Linked

"Richard A. Insel, MD., Executive Vice President, Research, at JDRF, said: "'These studies demonstrate that type 1 diabetes and celiac disease share far greater genetic overlap than had been appreciated, which helps explain the high prevalence of both diseases occurring simultaneously in an individual, and provide new avenues for understanding the cause and mechanisms of both diseases.'"

Apparently they found that people with these diseases share seven loci with each other, which is pretty crazy. I talked about this a few posts back, the correlation between these two diseases, but I thought it was only one gene that did it.

allergies: nature or nuture?

From the New York Times: Researchers Put a Microscope on Food Allergies

I find research like this pretty interesting, because 4/5 members of my immediate family have celiac disese, an allergy to certain types of grain proteins, especially in wheat, rye, barley, and oats. What causes allergies? Is it genetic or triggered by environment? My dad has it, and so do me and my two sisters. Recently I found out the same gene that can cause it has also been linked to thyroid disorders, which many of my mother's sisters have, and diabetes 1, which my grandmother had. So I wonder if my sisters and I got the gene from both sides, and that's why we have it.

A lot of people have wheat sensitivities, and I think a lot more people have celiac that don't realize it. Seems like autoimmune disorders are becoming more prevalent. I wonder if they're becoming more common, or just that we're noticing more?