Tags: genotype diet
Cover The Earth
November 14th, 2009 , by adminGrowing up in Brooklyn I remember many exciting and fun filled trips to Manhattan --or as anyone from Brooklyn calls it, “The City.” One of the features I always looked forward to seeing was a huge advertisement for a paint company that featured a can of paint pouring itself over a globe of the world, its byline proclaiming “We Cover the Earth with Our Paints.”

Excepting the obvious question as to why anyone would ever want to cover the world in it, paint is not a bad metaphor for how most scientists viewed inheritance before Mendel, it being a sort of “blended essence” --a mix of the features of both mom and dad, much like how we might combine white and black paints to make gray. In the late 1800s Charles Darwin proposed a mechanism of inheritance by means of gemmules, imaginary granules or atoms which are continually being thrown off from every cell or unit, and circulate freely throughout the system. Yet Mendel’s research showed that it was nothing of the sort; being in fact much more digital, like how a computer makes all sorts of interesting stuff out of what are essentially zeros and ones. Mendel’s theory nixed that notion completely, although after a while things started to be observed that appeared to indicate that genetics wasn’t all that black and white, on and off after all, but I’ll save that for a later story.
I’ve married a blue eyed woman, and have two daughters. The first daughter has brown eyes just like me. Simple enough: My brown-eyed alleles squash my wife's blue-eyed ones. However, my second daughter has greenish-hazel eyes, much lighter than mine or her sister, but certainly not bright blue like those of my wife, so it would seem like a little blending is going on over there after all. Eye color is not a simple dominant-recessive trait, although knuckle hair and tongue rolling are. The eye color trait is what geneticists call polygenic, which simply means that it is not decided by one single gene. In order to account for my younger child’s green-hazel eyes, we have to add other factors to the mix.
My wife is pure Irish on her mother’s side and a mix of Slovakian and Hungarian on her father’s. Hungarians have the highest percentage of green eyes of any population, close to 20%, so something in my wife’s blue-eyed world (the blue-eyed allele of her Hungarian father) produced a variant that refused to role over and die, but instead made alliances with other genes --including a recently discovered one that may go back to the Neanderthals--- that slips green eyes and red hair in between things, ultimately producing my younger daughter’s wonderful green eyes. Given that, you'd think I'd get the tongue rolling gene and she the knuckle hair, but alas, the results are quite opposite.
Many traits are polygenic, and when when added to the tremendously under-appreciated epigenetic effects on gene expression, explain why we have never found a single gene for diabetes, or cancer or Alzheimer’s disease. If it were that simple, we’d have had the answers to these questions already.
Another type of inheritance is very close to my heart. The allele (the set of alternate genes for any trait) for type O blood is recessive to the alleles for type B and type A. Again using my family as an example, biologically I am type A blood and my wife is type O. My daughters are both type A blood, so we know that they must have received a type O allele from mom and a type A allele from me. Their genotype for ABO blood type is A/o (recessive alleles are usually depicted in lower case, dominant in capitals, and genetic things are usually rendered in italics).
If I was instead type B blood and had provided a type B allele, the children would have type B, as type B is dominant to type O as well.
But here is where things get interesting. What happens if you were to receive one type A allele and one type B allele? Why, you would be blood type AB! The reason behind this is that although both B and A clobber O, they strike a tentative truce between themselves and split the kingdom and declare a dual monarchy. This is called co-dominance. There are not many instances of co-dominance in genetics, and ABO inheritance is almost always given as the example.
You may well ask why, if type O is recessive to types A and B, why hasn’t it disappeared, leaving only A and B to slug it out, and eventually producing a world of only type AB people? The reasons and proofs for this are mathematical, so I won’t bore you with them, but suffice it to say that if a population is large enough, and the individuals in that population tend to mate randomly, and there are no other major influences (such as one type being more resistant to an infectious disease), after one generation the gene pool will stabilize and reach a sort of equilibrium.
Since there is such a huge amount of o allele in the human population (so much so, in fact, that even though it is the recessive allele, individuals with type O blood constitute the majority of most populations around the world) it will keep propagating itself, whereas the type you’d have though would be replacing everyone else by now, AB, comprises at best about 2% of the population.
Most people probably have a negative concept of mutation, spawned by a slew of admittedly great science fiction. However, it might surprise you to learn that that vast majority of mutations, at least the ones that get incorporated into our genetic heritage, are not lethal and often don’t do very much at all. For example, let’s again turn to our trusty blood types. As we will explore in more later on in this book, genes are chunks of DNA that do things, like code for specific proteins. Although DNA is an incredibly long molecule (if all the DNA in all your cells was unwound and placed end to end it would produce a string capable of reaching to the sun and back several times) it is composed of a simple string of four repeating nucleotides abbreviated A,T,C and G. The sequence of these four repeating nucleotides is what contains the instructions for the protein.
The difference between having the gene for type A blood or type B blood is a variation of a mere seven letters out of the total of 1,062 that make up the entire gene. We even know exactly where they differ: letters number 523, 700, 793 and 800. If you are type A blood, you have C,G,C,G in these locations, whereas if you are type B blood you have G,A,A,C there instead. Yet however slight this difference is, it is enough to cause a major problem if you were to receive the wrong blood in a transfusion. These are called point mutations because they are a simple one-letter misspelling in a gene, unless as in the case of blood type it is a consistent variation that is inheritable, in which case it is called a polymorphism.
The type O gene mutation is even more interesting. It derives from a frame shift mutation. If you are type O you may be surprised to discover that rather than having a difference of letters, like A and B, you're just missing one letter, number 258, entirely.
So hopefully by now you are comfortable with the notion that mutations are just part of life, unless of course you are unfortunate enough to have gotten a lethal one (and there are many) which probably would never have allowed you to get so far in life as to be able to read this blog. Many, if not most, of these mutations are spontaneously terminated while the sufferer is still an embryo in utero. Virtually all of the well-known genetic disorders are semi-lethal.
There are may causes of mutations, including viruses and radiation, but the most common cause is the simple fact that when our cells reproduce, they must make a complete copy of there DNA, and sometimes the copies don’t turn out so great. Think about the photocopy of that great joke that circulated around the office cubicle the other day. If it was barely legible, with bloated letters that ran one into the other, it was probably because someone made a photocopy of the original, which was quite likely a photocopy of the previous copy. Each time a copy was made of a copy, the writing was degraded a bit more.
Genes are like that. Often as we get older, we tend to get more and more of this “photocopy effect”. Perhaps what was once a word string of CAG became CAA. Even if it is copied correctly, it will be CAA from there on. Perhaps not unexpectedly these mutations are called “copying errors” and given the enormous amount of cell division that goes on over the course of a lifetime it is the real surprise is just how good of a job we do at it.
Fascinating presidential election; certainly a very unique and historic outcome. It will be interesting to see --given the perilous state of affairs we find ourselves in-- whether 2008 is also the first presidential election in which (come January) it is the winner rather than the loser who demands a recount.
Tension and Relaxation
October 21st, 2009 , by adminYou are a collection of cells, literally trillions of them, each with a specific design and function. With a few exceptions, cells have a basic architectural design, most of the time being depicted as looking like a fried egg cooked sunny side up. However, in reality they are three dimensional beings, so it might be better to think of the average cell as a golf ball that you’ve cut across its midline. The “white” of our cell model is the body of the cell, and here are found many specialized areas called organelles that do particular jobs, much like our own internal organs have specific jobs as well. The “yolk” of our cell model is called the nucleus, and in this compartment there lies the object of our affections, the chromosomes.
Chromosomes were first discovered at the end of the 19th century by a German biologist named Walther Flemming. Flemming was looking at cells under a microscope and got the idea to use colors to dye the cell to make it easier to see things. The idea must have worked better than anticipated since he at once began to see spaghetti looking things in the nucleus that dyed a very deep color. As is the fashion, he named these entities chromosomes which is Greek for “colored bodies”.
Chromosomes are one of the more dynamic faces of Nature; they have to be, since they are responsible for the passing on of the Baton of Life that we call reproduction. The number of chromosome in the cell nucleus differs somewhat from species to species. We human have 46 chromosomes; dogs have 78; alligators 32; cabbage plants 18.
Your chromosomes are both the governess and chauffeur of the most important molecules in your body; DNA. Like any blueprint, DNA needs to read in order for the work order to be constructed. Now, DNA is a long, long molecule. If it were completely unraveled it would be about six feet long, yet so thin that it would be invisible. If the entire DNA, in every cell of your body, was stretched out and laid end-to-end in a straight line, it would reach to the sun and back over one thousand times.
I think an effective way of describing the dynamic qualities of the chromosome is to use a few metaphors. My older daughter likes to knit, so we often visit the knitting supply shop in town for fresh yarn. Yarn usually comes wrapped in skeins, a length of yarn wound around a reel. Most yarn comes in lengths of 80-150 yards. One of the nice things about buying yarn this way, rather than just as one long unwound string, is that you can put it under your arm and walk to the car. This is certainly better than tying a knot to the rear bumper and pulled the unwound string all the way home. Thus, the first important lesion of chromosome dynamics; if you’re going to reproduce you’ve got to stuff that entire DNA into a very small, tight package. Chromosomes are just that: tight packages of DNA.
On the other hand, it is very difficult, if not downright impossible to knit anything if the skein of yarn still has the paper label wrapped around it. In order to use the yarn, you have to unwind it. That’s the formula: when the cell needs to use DNA to get information about how to make a protein, it has to unwind it. When it needs to reproduce, or turn off the DNA information flow, it needs to concentrate and condense it.
DNA is packaged and concentrated by special proteins termed histones. This concentrated DNA is called chromatin, which is the DNA plus the histones that package DNA within the cell nucleus. Chromatin structure is also relevant to DNA replication and DNA repair.
Histones are very cool bead-like proteins that spool the DNA in a way that makes it either tighter or looser, sort of like the cardboard around which our skein of yarn is wrapped. Histones respond to changes in their structure by tightening the DNA wrap or loosening it. Whenever a cell needs to access the genetic information encoded in its DNA, the histones on the section of the DNA that is needed undergo a chemical reaction called acetylation by which a molecule called an acetyl group is stuck on the histones, causing them to relax and unravel. When business is concluded for the day, special enzymes come along and chomp off the acetyl group cause the histones to become de-acetylated, which makes them tighten up again, sending the DNA in the region back to its resting state. Think of it like this; when your DNA needs to work its histones chow down on acetyl groups for breakfast and they do yoga; when it needs to reproduce or shut down, the histones lift weights --the strain of which causes the acetyl group to pop out of their mouths.
Only until recent times have we understood this mechanism, and of its supremely paramount importance: That it is used by the environment to influence gene function and that influence, for either good or bad, can be passed on as inheritance. Amazingly, we not only inherit the genes from our parents, but state of histone acetylation of the genes as well. Thus, the histone acetylation patterns of the genome are a prime mechanism of epigenetic inheritance, along with DNA methylation.
Scientists have given each human chromosome a number, according to its size; thus chromosome number 1 is the largest, then number 2, etc. Chromosomes come in pairs, one from each parent. So there are 23 pairs, for a total of 46 in us humans. Numbers 1-22 are non-sex chromosomes called autosomes, and pair 23 contains the X and Y sex chromosomes.
In the few minutes it has taken to read up to here, this, around 400 million of your red blood cells were depleted and replaced, consistent with the set of genetic instructions contained in your DNA. This is where the genetic code comes in.
IFHI 2009: Fully Booked!
May 12th, 2009 , by adminI'm just back from a site visit to the Dolce Conference Center, scene-to-be of the upcoming IFHI 2009 Conference and Certification. What a facility! If you've been to the Buttes for 2005 or 2007 prepared to get gob-smacked! The premises (a former monastery) are just gorgeous this time of year. The intimacy of the lecture halls combined with the terrific AV capabilities of the facility already have my mind running in overdrive. I think it was very smart to top the attendance at 125. This will insure that everyone feels that they are a real part of the event.
Unfortunately, despite the fact that the conference is three weeks away, I'm told that all available rooms at the Dolce Conference Center have been taken. We have a few seats still available for the day sessions, and if anyone plans to register from this point on, we can book them at the nearby Double Tree Inn and the Dolce will bus these folks back and forth.
Anyway, if you want to attend IFHI, even at this late point in the process, contact IFHI Conference Services and maybe they can work something out for you.
The Weekly Transfusion 1.2
March 23rd, 2009 , by adminHere it is.. another Monday and another research grab-bag.
Five daily portions of fruits and vegetables raise serum antioxidants in three months
To explore the effects of increasing fruit and vegetable intake and the resulting effects on levels of circulating micronutrients in a community-dwelling population with an already high consumption of fruits and vegetables, 112 volunteers (86% women) underwent targeted dietary counseling for three months. At the beginning of the study and after 4, 8 and 12 weeks a food frequency questionnaire was filled in, and plasma levels of dietary antioxidants as well as biomarkers of oxidative lipid and protein damage were determined. Compared to baseline, especially the intake of fruits was significantly improved after 3 months of intervention, and mean plasma levels of lutein, zeaxanthin, β-cryptoxanthin, lycopene, α- and β-carotene, retinol, α-tocopherol, vitamin C and vitamin B6 were increased. Biomarkers of oxidative stress remained unchanged. Thus, a nutritional counseling program is capable of improving plasma levels of antioxidants even in a health-conscious population.
Article Link
Comment:
What is especially interesting about this study was that they used individuals who were already eating a pretty healthy diet, which just goes to show that even if you follow the BTD or GTD in terms of food choices, something as basic as making sure that you get the required amounts of recommended fruits and vegetables can make a big difference.
Schizophrenia, gluten, and low-carbohydrate, ketogenic diets
We report the unexpected resolution of longstanding schizophrenic symptoms after starting a low-carbohydrate, ketogenic diet. After a review of the literature, possible reasons for this include the metabolic consequences from the elimination of gluten from the diet, and the modulation of the disease of schizophrenia at the cellular level.
Article Link
Comment:
Previously, Dohan (Acta Psych Scand 1966, 42(2):125-152) observed a decrease in hospital admissions for schizophrenia in countries that had limited bread consumption during World War II, which suggested a possible relationship between bread and schizophrenia. Early work with lectins clearly showed that the brains of schizophrenics bind lectins differently than the brain tissue of non-schizoprhenics, which appears to make sense in that the carbohydrate content of schizophrenic brain tissue (in addition to dementia and a few other illnesses) revealed the existence of spherical deposits in the inner and middle molecular layers of the dentate gyrus in the hippocampal formation which contained fucose, galactose, N-acetyl galactosamine, N-acetyl glucosamine, sialic acid, mannose and chondroitin sulfate; many of these blood group active carbohydrates with known lectin binding affinities (link).
Over the years some of the most stirring letters I've received from book readers have centered around improvements in family members with schizophrenia. Almost all of these letters have been from or about blood type O schizophrenics, which may mean that the nutritional approach to schizophrenia might necessarily differ by foods and blood type. We are now only beginning to understand the effects of tissue glycosylation on the development and maintenance of brain neural networks (in particular those utilizing the blood group O specific antigen fucose).
Lectin-epithelial interactions in the human colon.
Similar changes in glycosylation occur in the colonic epithelium in inflammatory conditions such as ulcerative colitis and Crohn's disease and also in colon cancer and precancerous adenomatous polyps...Tools are now available to allow fast and accurate elucidation of glycosylation changes in epithelial disease, characterization of their potential lectin ligands, whether dietary, microbial or human, and determination of the functional significance of their interactions. This should prove a very fruitful area for future research with relevance to infectious, inflammatory and cancerous diseases of the epithelia.
Article Link
Comment:
In years past I've written about the effects of some dietary lectins on the cells of the colon, in particular the lectins found in mushrooms, fava beans and jackfruit. Most of the plant lectins are specific for the Thomsen-Friedenreich Antigen (T antigen) a pseudo blood group antigen which is often expressed in pre-malignant cells of the colon.
Here is a quote from a study examining fava (broad) bean lectin:
VFA stimulated an undifferentiated colon cancer cell line to differentiate into gland like structures. The adhesion molecule epCAM is involved in this. Dietary or therapeutic VFA may slow progression of colon cancer.
Here is a quote from a study examining standard commercial supermarket mushroom lectin:
Agaricus bisporus agglutinin (ABA) isolated from edible mushroom has a potent anti-proliferative effect on malignant colon cells with considerable therapeutic potential as an anti-neoplastic agent.
Here is a quote from a study examining jackfruit lectin:
(Jacalin) Lectin binding to human colonocytes can predict the presence of malignant and premalignant lesions of the colon, and has potential as a noninvasive screening tool for colorectal neoplasms.
If you have a family history of colon cancer, or have been diagnosed with colon abnormalities (such as polyps) you may want to investigate adding more of these foods to you diet (using the BTD as a guide to which would be best for you)
Human pseudogenes of the ABO family show a complex evolutionary dynamics and loss of function.
The GT6 glycosyltransferases gene family, that includes the AB0 blood group, shows a complex evolution pattern, with multiple events of gain and loss in different mammal species.These results suggest that some of these GT6 human pseudogenes may still be functional and retain some valuable unknown function in humans, in some case even at the protein level. The evolutionary analysis of all members of the GT6 family in humans allows an insight in their functional history, a process likely due to the interaction of the host glycans that they synthesize with pathogens; the past process that can be unravelled through the footprints left by natural selection in the extant genome variation.
Article Link
Comment:
Pseudogenes have been defined as nonfunctional sequences of genomic DNA originally derived from functional genes and are sometimes referred to as 'Junk DNA.' However new finding are suggestive that these areas of non-coding DNA and RNA may be involved in developmental changes which differentiate the functions linked to the blood type genes that occur between the various species.
Another nail in the coffin for the 'animals have blood types and don't eat right for their type' criticism of the Blood Type Diet by the nincompoop Andrew Weil.
The Effect of ABO Blood Types on Periodontal Status.
A relatively higher percentage of A group patients was found in gingivitis group and relatively higher percentage of O group patients was found in periodontitis group. A significant relationship was also determined between Rh factor and gingivitis. ABO blood subgroups and Rh factor may constitute a risk factor on the development of periodontal disease. However, long-term studies are needed to make a more comprehensive assessment of the effects of ABO group on periodontal diseases.
Article Link
Comment:
I'm sure that secretor status had something to do with these results, since it has an effect on pellicle formation (link) I do however, agree with the results. In my own patients I have seen periodontal disease resolve easily in many type A's by simply getting their gingivitis under control. Type O's on the other hand have a harder time of things, especially if their protein intake is not adequate.
That's about it for this week.
A bit of news: I would be willing to entertain questions about topics that might be of interest to this community. Just drop a comment (link is below). I will not however, respond to questions of a personal medical nature, nor give medical advice. Thanks for respecting this caveat.
Gee.. Do you think they're describing the Explorer?
March 2nd, 2009 , by adminFrom Percept Mot Skills. 2008 Dec;107(3):737-46.
Twin and family study findings indicate a substantial heritability of digit ratio (2D:4D), a putative marker for the masculinizing effects of prenatal androgen exposure. Functional polymorphisms of the X-linked androgen receptor gene, i.e., androgen sensitivity, contribute somewhat to the expression of 2D:4D in men, but otherwise the genetics of 2D:4D is unknown. This study investigated differences in 2D:4D by self-reported ABO blood type and Rhesus factor, two easily collectible genetic traits, in two samples (combined N=1273). Effects of blood groups on 2D:4D were small and not significant in all tests in both samples; however, two consistent patterns emerged across samples. Of the ABO types, AB had the lowest right-hand 2D:4D, the highest left-hand 2D:4D, and the lowest right-minus-left difference in 2D:4D, and Rhesus factor Rh- had higher left-hand 2D:4D and lower right-minus-left difference in 2D:4D than Rh+. If replicable, this may suggest genes contributing to the expression of 2D:4D reside in the vicinity of the gene loci (chromosomal locations: 9q34.2 and 1p36.11) of these blood groups or pleiotropic effects of the blood-group genes.

