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Genetics, Vol. 170, 1839-1847, August 2005, Copyright © 2005
doi:10.1534/genetics.104.040360
The Genetic Basis of Resistance to Anticoagulants in Rodents
Hans-Joachim Pelz*,1, Simone Rost,1, Mirja Hünerberg, Andreas Fregin, Ann-Charlotte Heiberg, Kristof Baert, Alan D. MacNicoll**, Colin V. Prescott, Anne-Sophie Walker, Johannes Oldenburg and Clemens R. Müller,2
ABSTRACT
Anticoagulant compounds, i.e., derivatives of either 4-hydroxycoumarin (e.g., warfarin, bromadiolone) or indane-1,3-dione (e.g., diphacinone, chlorophacinone), have been in worldwide use as rodenticides for >50 years. These compounds inhibit blood coagulation by repression of the vitamin K reductase reaction (VKOR). Anticoagulant-resistant rodent populations have been reported from many countries and pose a considerable problem for pest control. Resistance is transmitted as an autosomal dominant trait although, until recently, the basic genetic mutation was unknown. Here, we report on the identification of eight different mutations in the VKORC1 gene in resistant laboratory strains of brown rats and house mice and in wild-caught brown rats from various locations in Europe with five of these mutations affecting only two amino acids (Tyr139Cys, Tyr139Ser, Tyr139Phe and Leu128Gln, Leu128Ser). By recombinant expression of VKORC1 constructs in HEK293 cells we demonstrate that mutations at Tyr139 confer resistance to warfarin at variable degrees while the other mutations, in addition, dramatically reduce VKOR activity. Our data strongly argue for at least seven independent mutation events in brown rats and two in mice. They suggest that mutations in VKORC1 are the genetic basis of anticoagulant resistance in wild populations of rodents, although the mutations alone do not explain all aspects of resistance that have been reported. We hypothesize that these mutations, apart from generating structural changes in the VKORC1 protein, may induce compensatory mechanisms to maintain blood clotting. Our findings provide the basis for a DNA-based field monitoring of anticoagulant resistance in rodents.
Originally posted by Heronumber0
Just to introduce some balance melatonin, you did mention some favourable genetic mutations in humans but neglected to mention that the vast number of genetic mutations, by a mile, are deleterious:
Genetic Diseases
Moreover, although the Apo -AI Milano genetic variant is favourable against ischaemic heart disease, how does it spread through the human population by Natural Selection unless most people with heart disease die and these people are left to repopulate the Earth from a genetic bottleneck - a ridiculous scenario!
Anyway, melatonin, I hope 2008 is better for you than 2007. Best wishes mate.
Originally posted by melatonin
Most mutations are actually neutral.
Nachman & Crowell (2000)
A thalassemic beta-globin gene cloned from a haplotype I chromosome contains a T to G transversion at position 116 of IVS1 which results in the generation of an abnormal alternative acceptor splice site. Transient expression studies revealed a 4-fold decrease in the amount of RNA produced with greater than 99% of it being abnormally spliced despite preservation of the normal acceptor splice site at position 130. These results suggest that the mutation at IVS1 position 116 results in beta zero thalassemia.
I think the idea is that with such poor diets and sedate modern lifestyles, protection from the effects of high cholesterol will have positive benefits. Indeed, it is pretty easy to see that sugar-daddies with this gene might well be pumping out sprogs much longer than people without (well, they would if all was equal).
Originally posted by ppkjjkpp
"There are 1,051,200,000,000,000 minutes in 2 billion years and there are 1,000,000,000,000,000 connections in the brain.. In order to evolve that many connections, evolution must produce by sheer accident approximately one organized, perfected, in place and fully functional connections every minute for 2 billion years*
Evolution of primary microcephaly genes and the enlargement of primate brains.
Curr Opin Genet Dev, 15(3):241-8.
Abstract
Brain size, in relation to body size, has varied markedly during the evolution of mammals. In particular, a large cerebral cortex is a feature that distinguishes humans from our fellow primates. Such anatomical changes must have a basis in genetic alterations, but the molecular processes involved have yet to be defined. However, recent advances from the cloning of two human disease genes promise to make inroads in this important area. Microcephalin (MCPH1) and Abnormal spindle-like microcephaly associated (ASPM) are genes mutated in primary microcephaly, a human neurodevelopmental disorder. In this 'atavistic' condition, brain size is reduced in volume to a size comparable with that of early hominids. Hence, it has been proposed that these genes evolved adaptively with increasing primate brain size. Subsequent studies have lent weight to this hypothesis by showing that both genes have undergone positive selection during great ape evolution. Further functional characterisation of their proteins will contribute to an understanding of the molecular and evolutionary processes that have determined human brain size.
Originally posted by Heronumber0
I take your assertion and agree with it to a point. However, the paper you cited is about the rate of mutation in pseudogenes and I would criticise that study because much of the change in pseudogene sequences may be neutral anyway.
In fact one of the diseases - beta thalassaemia, is caused by a single base pair substitution:
1. Is there an obvious link between cholesterol levels and heart disease. Some investigators disagree with this simple association, certainly in middle-aged men in London, if not elewhere:
2. To successfully spread this gene, the carriers of Apo AI Milano would have to be sexually active up to middle age and have a significant number of progeny. Europeans do not seem to fall into this categorisation.
Also, I think, from the paper, that this is a rare variant found in one family, so it is not widespread at the moment anyway.
I had to be exposed to the TV Hogmanay celebrations with kilted men full of whiskey throwing themselves around a room shouting Wheeuch! and Och Aye! at each other to the accompaniment of the bagpipes - still, we can't all have everything can we?
Originally posted by melatonin
Aye, and being a mere carrier of these genes may actually be beneficial in particular environments. I don't doubt that people suffer from negative mutations, I actually stated this earlier. But the chances are very high that we all have numerous mutations in our genome, most being pretty innocuous - well I hope mine are...
OK, I know some people question this, but are you saying that clogged arteries are nothing to worry about, and that protection against this is not beneficial? This is what this mutation appears to be protecting against. Moroever, I pointed out more than one mutation earlier, so I don't see what the point of this is, unless it's an obscuration. One study using an APO-milano derived therapy appeared to have positive effects.
The requirement was to point out beneficial mutations, I did so. even if you want to doubt the protection provided by APO-milano, others are still outstanding. Moreover, I can find more if need be.
Originally posted by GT100FV
reply to post by apex
You're confusing adaptation with mutation. Were Europeans mutants because they'd adapted to the diseases that the South American Indians had no defense against?
mutation
1. an alteration or change
The CCR5 mutation is more common in those of European descent. One theory for the etiology of the relatively high frequency of CCR5-Δ32 in the European population is that it conferred resistance to the bubonic plague in mid-14th century Europe. People who had this mutation were able to survive infection thus its frequency in the population increased.
Originally posted by Heronumber0
As I mentioned earlier, I am willing to agree that there are many neutral mutations in the genome (up to over a hundred mentioned by the paper) which may be neutral. However, we disagree at the point where a disease exerts an effect on the phenotype of the individual.
....
I am not trying to obscure or obfuscate. I am trying to make the point that sometimes a single base change in the DNA can lead to debilitating disease.
I did not get a chance to read the whole paper on APO milano so you can inform me if HDL and LDL ratios were taken into account.
I have found about 7 beneficial mutations but many more non-beneficial mutations as stated above.
Originally posted by jedimiller
You don't see the evidence eh? have you looked around? you should go see the show where they show the human body, it's a tour-museum type called bodies. the human body alone is all you need to know that there was a creator. it's like making a car, do you need to see someone build the car to know it was created? the same with the human body, it's perfect, it has organs that do different things, brain funtions. nerves. muscles. and it's all organic. Now please do you think that evolution can do that? no way..evolution can only change what has already been there..