Tag Archives: Basic Science

Oh, noes, GMOs!

Oh, noes, GMOs!


Everyone calling vociferously for labeling GMOs on the internet seems to go silent when they are asked specific questions about why, and how much labeling they’re actually asking for. Turns out, they usually don’t know how genetic modification is done, how many different kinds of modifications there are, how much actual potential harm there is or isn’t, or, quite frankly, how digestion works. (If it worked the way some alarmists believe it does, I’m afraid we might have to turn to cannibalism!)

Labeling something “Contains GMOs” is not only uninformative and misleading, but will add an average of $500 to each American’s food bill if it were to be instituted. Also, in order for a label to be useful and valid, it would need to be much more detailed. So I would like to break it down a little more realistically.


Bacillus thuringiensis is applied liberally on organic crops to control pests. Catalogs that sell Bt to home gardeners describe it as “Bacillus thuringiensis (Bt) is a natural occurring, soil-borne bacteria that has been used since the 1950s for natural insect control.” (Planet Natural) and “Bt is a naturally occurring bacteria with many powerful insect-specific strains. Like other biologicals, Bts biodegrade in sunlight and may require reapplication. Bt for Caterpillars & Worms: Safe for the user and the environment, Bacillus thuringiensis v. kurstaki is a pest control mainstay for organic vegetable growers.” (Grow Organic) You would not find any food in the supermarket that would be labeled “Genetically modified with Bt,” because those crops are not used to feed people, but for animal feed and other industrial uses. You would, however, find lots of foods labeled “Sprayed with Bt,” at least if labeling were honest.

So why is it that Bt is safe and organic when sprayed in large quantities (where it drifts and affects insects that are not feeding on the crops, including some beneficial species) but suddenly becomes “Bt toxin” when it is engineered into the crop and affects only the pests that feed on the crops? The EPA has done thorough testing on Bt (http://www.epa.gov/pesticides/biopesticides/pips/regofbtcrops.htm) and assured that GM crops with the gene that produces the Bt protein are not in foods meant for human consumption, even though humans do not have the body chemistry that allows Bt to be absorbed.

Big Organic wants to have its cake and eat it, too. In order to continue using Bt itself for pest control, but demonize it as a toxin when it’s made by the plant itself, the very sites that make these statements do some unscientific speculation as to how this is so and present it as factual. Were they to admit that Bacillus thuringiensis is Bacillus thuringiensis and is harmful only to specific species (not human) that are directly exposed to it, they would not be able to continue their hypocritical campaign to use and sell it while simultaneously representing it as a life-threatening dangerous substance.


You would see “Roundup Ready,” but that would be pretty uninformative, also, because many crops that are not “Roundup Ready” are treated with Roundup, because it is an effective dessicant. For example, a wheat farmer would use it to kill and dry his entire field so that all the wheat would be usable, and would not need careful (and expensive) sorting to ensure that a few green grains wouldn’t rot an entire silo of harvested wheat. So, GMO or not, a label saying “glyphosate exposed” would be much more useful. That, however, would be a decision one should make based on environmental concerns rather than personal ones, because glyphosate is toxic to humans in such large doses that you would need to drink about three gallons of it straight to get sick.


There would also have to be a label for trans-species modification. Scientists take a gene for a trait from one species (usually another species of something that we also eat, so we’re eating that gene already, just in some other food) and insert it into another. You would need to do some serious mental gymnastics to see how this would be harmful. You would also have to start giving up a lot of foods, organic or otherwise, because this is also used to protect crops against diseases that would wipe them out. Bananas and papayas and oranges would no longer exist, or might go extinct in the future, without the modifications that allow them to resist the fungi that kill them. You might also want to check out foods that contain other foods, and perhaps stop using recipes. Your Manhattan Clam Chowder has fish genes and tomato genes. . .


The last label would be a cross-species modification. This is when a gene for a particular trait is taken from one species and transferred to a related species – like the gene from one type of salmon that triggers larger size to a smaller sized salmon. Again, if you were to avoid foods with this label, you would need to deny yourself foods that have been cross-bred and hybridized by man for thousands of years, which would be everything we eat. It’s the same process, but accelerated and without the negative characteristics of traditional manipulation by sexual selection.

Look at what we’ve done to purebred animals – hip dysplasia in German Shepherds, seizures in Boxers and Spaniels. . .When we tried to breed a rot-resistant potato by hybridization, we ended up with a potato that was kinda poisonous. Genetic modification is working on a rot-resistant potato that won’t make you sick.


Golden rice was created by moving a gene that produces Vitamin A from the leaves and stem of the plant to the grain. This is a technology that may be applied to other species later on. People destroying entire crops of golden rice because it’s GMO is an example of uninformed hysteria. So we’d need a label for this at some point.

If all you want is a nice, simple label that says “Contains GMOs” so you can make buying decisions without thinking, then stick with buying things that say “GMO-Free.” The GMO labeling being proposed by the Organic Foods Industry is not designed to inform or help people make healthy decisions, but to direct buyers to their own products. If you want labels that actually give you useful information, they’re going to be on almost every item in the store, and it’s going to cost all of us. And if you really want to know what’s in your GM food, check the EPA, the ISAAA’s GM Approval Database, and consumer information from the FDA.

If you want to see why the studies being cited as proof that GMOs are dangerous are not valid evidence, here are a few links. Academics Review looks at a large selection of studies and explains what they actually found and whether those findings are accurate. The Seralini rat tumor study was so deeply flawed that even a low-impact journal retracted it out of embarassment – lots of scientific explanation and criticism is collected at David Tribe’s blog. Skeptical Raptor breaks down the information in a recent meta-analysis of 1,783 studies, including at least 600 independently funded, which found no tangible dangers and many benefits of GM crops.

(Image source Also a good article!)

Where I Go For Science

Where I Go For Science

A friend of mine asked me for a few links to science sites so she could learn a little more, so I set to copying and pasting my bookmarks for her. Now I know why I lose so much time sitting at the computer. Most of these sites are life sciences, so sorry about the lack of Chemistry and Physics and such. Here’s the list. . .

Sites in my WordPress Reader, loosely arranged by subject:

Skepticism/Critical Thinking
Science or Not?
I fucking hate pseudoscience
Edzard Ernst
Why Evolution is True
Violent Metaphors

Brain Stuff
Left Brain Right Brain
Mind Hacks
Neurologica Blog
Wiring the Brain
Science Over a Cuppa
Gabriela Tavares
BPS Research Digest

Science Based Medicine
Science-Based Pharmacy
Science-Based Life
Drug Monkey

Bits of DNA
Code for Life

Skeptical Raptor’s blog
Shot of Prevention
The Poxes Blog

Other. . .
Inspiring Science
Double X Science
Bishop Blog

Not on wordpress:

Not Exactly Rocket Science Not only a lot of interesting articles on Biology, but a weekly roundup of interesting links. (You can also visit The Loom and Only Human from here, plus some others, but these three are my favorites.)
In The Pipeline Chemistry, but a lot of it related to Pharmaceuticals.
Skeptical Medicine A critical look at both conventional medicine and pseudoscience.
Scitable Nature Publishing Group’s educational site.


Research Blogging
Science News (limited access for free, but still a lot of good science.)
Science Seeker (you can filter what you see by checking the subject boxes to the right.)

I’m always checking for new places, especially those that would be good for people who are not scientists, but want to understand. I’ll take suggestions for anything that’s not behind a paywall or too difficult for non-academics!

Learning From Research – The Discussion

Learning From Research – The Discussion

It’s been a while, and I’ve had a lot of stuff going on both in my life and in my mind, but I’m determined to finish this thing. Previous posts:

Part 1
Part 2

This is the section in which everything that was talked about before is kind of recapped and explained and, well, justified. I approached this in a much simpler format, because that’s really all it needs. My comments are bolded.


It was first demonstrated here that the fidelity of replicating methylation patterns of CGIs in the promoter regions is significantly higher than that of CGIs outside the promoter regions. (CGIs in promoter regions replicate themselves more accurately than the ones outside of promoter regions.) It was also demonstrated here that methylated genomic regions show much higher fidelity than unmethylated genomic regions. (If the genes are methylated, they tend to stay methylated, if they’re unmethylated, they can become methylated.) These showed that maintenance methylation of hemimethylated CpG sites into fully methylated CpG sites at DNA replication was highly reliable, while unmethylated CpG sites tended to be methylated by de novo methylation. (Methylation sticks.) It is well-known that exogenous DNA is exposed to a de novo methylation pressure (Doerfler et al. 2001; Bird 2002), and a similar methylation pressure seems to be working on the endogenous DNA. (Unmethylated sites are vulnerable to methylation from outside sources.) To maintain the unmethylated status of CGIs, protection mechanisms from the de novo methylation pressure seem to be necessary. (Unmethylated CGIs need something that protects them from methlyation or they’re vulnerable to it.) Since the MPERs were significantly lower in CGIs in the promoter regions than in CGIs outside the promoter regions, the presence of a protection mechanism(s) specific to the promoter regions, in addition to a mechanism(s) common to all CGIs, was indicated. (Promoter region CGIs probably have stronger protection against methylation of unmethylated regions, because they resist methylation better than non-promoter-region CGIs do.) Although the details of the mechanisms are still unknown, binding of transcriptional factors, such as Sp1, has been indicated as a promoter-specific mechanism (Han et al. 2001). (Hint, hint – this is something someone might want to look into, guys, ‘cuz our grant has been spent! Heh.)

The differential fidelities in replicating methylation patterns of CGIs in the promoter regions and those outside indicated that aberrant methylation of CGIs would occur at different rates depending upon their locations. This will be important when tumors are analyzed for the CGI methylator phenotype (CIMP), which are considered to be caused by molecular defects that allow accumulation of aberrant CGI methylations (Toyota et al. 1999). The differential fidelities shown here suggest that there are two types of CIMP, one due to a defect(s) in the protection mechanisms common to all CGIs and the other due to a defect(s) in the protection mechanisms specific to CGIs in the promoter regions. Actually, a correlation between the CIMP and the diffuse-type histology was clearly observed in gastric cancers when CGIs in the promoter regions were used for CIMP analysis (Kaneda et al. 2002b), while it was unclear when CGIs outside the promoter regions were used. (This will help us do more research that will help with cancer prediction/prevention/treatment, in case you don’t think that these findings have a worthwhile purpose of their own. When in doubt, reference cancer. For people with maybe a little less vision or curiosity. Just sayin’.)

In order for an impaired fidelity in maintaining a methylation pattern to exert any biological effect, methylation statuses of multiple CpG sites in a CGI must be altered. (One change at a single location isn’t going to make a big difference.) A significant increase of MPERs would be necessary for this, and quantitative analysis of MPERs in cells with suspected increase of MPERs is necessary. (We don’t know how many besides “more than one,” so another study would be required.) DMR of the H19 gene had a polymorphism at nt. 391 (nt. 8217; GenBank accession no.AF125183), and this served to distinguish the two alleles clearly. (This location was where we could best see what happened.) The G-allele was methylated in all of the six cultures, and the T-allele was unmethylated. The methylation patterns of the T-alleles were similar in HMEC11 and HMEC15, but were essentially variable among the six cultures. This indicated that, although the original cells in HMEC11 and HMEC15 might have had a common ancestral cell, methylation patterns in a tissue alter significantly during a human life span. (Methylation may change because of time, not necessarily because something came in and methylated stuff. No pointing at a specific environmental influence like a chemical or somesuch. Just demonstrating that it happened, and where and why it would be more or less likely to happen.)

Future clarification of what protection mechanisms are involved and how they are impaired in various diseases will contribute to understanding of aging (Ahuja et al. 1998; Issa et al. 2001) and various pathological conditions. (This is a single step in a huge process, but it puts us on a track to learning more than what we know now.)