Post by jamshundred on Feb 10, 2013 16:14:01 GMT -5
Re: Registration Question
« Reply #39 Yesterday at 4:05pm »
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Feb 8, 2013, 10:15pm, genebo wrote: From page 81 of an article presented to the First World Dexter Congress:
Gill (Gill, 1998) gives the likelyhood of even two such occurrences as 1 in 10,000,000,000. Therefore, the origin of these polled animals has to be sought elsewhere. "
KIRK>>He should have said... It's 100% POSSIBLE for these mutations to occur and they may well have done so, but due to the low probability, it raises doubt.
It raises doubt with me that your correction of a PHD genetic researcher
is correct. Tell me how many mutations have come into the Dexter breed in 100 years that have been proven to actually be a mutation from Dexters?
1. Dun - - This is iffy. I know there is research in the scientific journals but read the list of animals that were part of the research. With pedigree research one quickly discovers there is one major breed available that should have been tested but was not. We can discuss this at another time but there were NO dun descendents from a "brown" cow that was recorded in early records but was more likely a red cow because of the ancestoral herd. Doesn't matter. No dun descendents. So dun had to come to America no earlier than the 1950's based on pedigree research.
Save dun for another day and thread.
2. PHA. Interesting that PHA came from the same herd that brought the modern dun in from Canada in 1982. Woodmagic.
3. Polled - Came to America on imported semen in early 1990's. Animal had a great grandmother that was Angus, and the original mutation came from a herd with a background in upgrading and this polled event was never documented scientifically - although the science was available.
No other diseases or mutations of record from the beginning of the breed.
In England the Woodmagic herd was closed in the late 1970's/early 1980's. This herd had A1 genes, dun genes, but NO polled genes. The first two were likely not mutations in this particular herd as there is evidence otherwise, but that there is NO polled IS significant when one looks at the pedigree of Godstone Esmeralda and sees the number of Woodmagic animals. She is more Woodmagic than anything else!
In America the US herd was primarily a "closed herd" until the 1950's when there were a few imports from England, and again two cows ( Parndon) in the 1960s. There were NO mutations. There were NO polled Dexters. There was NO PHA. There is no proof of dun animals either. The dun cannot be confirmed until after the 1950 imports which have heritage back to the UK herd where dun can be traced behind Woodmagic and/or the Woodmagic dun imports to Canada and then to the US in 1978/1982.
Feb 8, 2013, 10:15pm, genebo wrote:
Some very significant information has recently come to light, with UC Davis's announcement of a test for polled in cattle. The test is for two different types of polledness. One is of the Friesian type, PF, and one is of the Celtic type, PC. The Dexter cattle tests have been coming back having tested positive for the Celtic type, the same as found in Angus, Blonde d’Aquitaine, Dexter, Limousin, Charolais, and Hereford, among others.
It's important to note that it is the same gene. The likelyhood that Dexter cattle could be polled as a new gene mutation, that was exactly the same as the gene that causes pollednes in the other British breeds is beyond calculation. The gene that causes polledness in Dexters tests to be the same as Angus, et al, (Celtic PC) and can be distinguished from Fresian PF. This new information indicates that we can forget about the possibility that there is a third type of polledness unique to Dexters (polled Nonexistum PN).
Kirk: >>Actually, some genes are prone to mutate in certain ways and some mutations are NOT as random and rare as once thought. It's possible that the 2 types of polled mutations found so far have freshly occurred many times in many different breeds. It's sorta like common misspelling of words where lots of folks repeatedly spell a word wrong in exactly the same way. If I misspell a word the same way you misspell a word, it doesn't mean that I copied you.
"There are multiple ways for point mutations to occur. First, ultraviolet(UV) light and higher-frequency light are capable ionizing electrons and in turn impacting DNA. Also, one of the cell metabolic byproducts, reactive oxygen molecules with free radicals, can also be very harmful to DNA. These reactants can lead to both single-stranded DNA breaks and double-stranded DNA breaks. Third, bonds in DNA eventually degrade, which creates another problem to keep the integrity of DNA to a high standard. There can also be replication errors that lead to substitution, insertion, or deletion mutations.
It was previously believed that these mutations happened completely by chance, with no regard for their effects on the organisms. Recently, there have been studies suggesting that these mutations occur in response to environmental challenges. That is to say, they are more likely to occur when they are advantageous to the organism, rather than when they are neutral or disadvantageous. [1]"
Kirk . . all of that is just selective crappy theory. There is so little of even circumstantial evidence to substantiate mutations in the Dexter breed versus introgression it is not even worthy of this repeated attempt to suggest otherwise.
en.wikipedia.org/wiki/Repeat_induced_point-mutation
"Some mutations occur more frequently when they are advantageous than when they confer no advantage. While we generally speak of spontaneous mutations being random, we are also aware that they are not truly distributed at random. There are hot spots for mutations, and some kinds of substitutions occur more often than others".
Kirk, anyone can put anything or change anything on Wikipedia. Puleeze.
Kirk >>http://www.genetics.org/content/126/1/5.full.pdf
Horns are VERY expensive to an animal and primarily useful to fight off LARGE predators. If some horned animals made their way to an island with no large predators, it would be advantageous to be able to eventually eliminate the horns (but it could be useful to hide some recessive horned genes in case the horns were needed again in future generations).
Oh my goodness. This is painful to read.
First and of utmost importance. . . . Dexter cattle are the smallest breed of HORNED European cattle. And they are small in number which makes it easier to change this breed entirely. That would simply be a disaster but it gets closer and closer. Owners and breeders have to decide if they wish to be part of the extinction of a beloved breed whose numbers were so low in recent decades they were on the endangered species list. Think on that! ! Think on species that we have almost lost and preservation efforts have saved them. . . . ( The American Eagle is my favorite).
Would we want the very foundation of our breed to be lost?
The horns are beautiful and rarely threatening and most assuredly manageable. They are not on Dexters only for predator control. . . the designer gave them other important functions as well.
Judy
« Reply #39 Yesterday at 4:05pm »
--------------------------------------------------------------------------------
Feb 8, 2013, 10:15pm, genebo wrote: From page 81 of an article presented to the First World Dexter Congress:
Gill (Gill, 1998) gives the likelyhood of even two such occurrences as 1 in 10,000,000,000. Therefore, the origin of these polled animals has to be sought elsewhere. "
KIRK>>He should have said... It's 100% POSSIBLE for these mutations to occur and they may well have done so, but due to the low probability, it raises doubt.
It raises doubt with me that your correction of a PHD genetic researcher
is correct. Tell me how many mutations have come into the Dexter breed in 100 years that have been proven to actually be a mutation from Dexters?
1. Dun - - This is iffy. I know there is research in the scientific journals but read the list of animals that were part of the research. With pedigree research one quickly discovers there is one major breed available that should have been tested but was not. We can discuss this at another time but there were NO dun descendents from a "brown" cow that was recorded in early records but was more likely a red cow because of the ancestoral herd. Doesn't matter. No dun descendents. So dun had to come to America no earlier than the 1950's based on pedigree research.
Save dun for another day and thread.
2. PHA. Interesting that PHA came from the same herd that brought the modern dun in from Canada in 1982. Woodmagic.
3. Polled - Came to America on imported semen in early 1990's. Animal had a great grandmother that was Angus, and the original mutation came from a herd with a background in upgrading and this polled event was never documented scientifically - although the science was available.
No other diseases or mutations of record from the beginning of the breed.
In England the Woodmagic herd was closed in the late 1970's/early 1980's. This herd had A1 genes, dun genes, but NO polled genes. The first two were likely not mutations in this particular herd as there is evidence otherwise, but that there is NO polled IS significant when one looks at the pedigree of Godstone Esmeralda and sees the number of Woodmagic animals. She is more Woodmagic than anything else!
In America the US herd was primarily a "closed herd" until the 1950's when there were a few imports from England, and again two cows ( Parndon) in the 1960s. There were NO mutations. There were NO polled Dexters. There was NO PHA. There is no proof of dun animals either. The dun cannot be confirmed until after the 1950 imports which have heritage back to the UK herd where dun can be traced behind Woodmagic and/or the Woodmagic dun imports to Canada and then to the US in 1978/1982.
Feb 8, 2013, 10:15pm, genebo wrote:
Some very significant information has recently come to light, with UC Davis's announcement of a test for polled in cattle. The test is for two different types of polledness. One is of the Friesian type, PF, and one is of the Celtic type, PC. The Dexter cattle tests have been coming back having tested positive for the Celtic type, the same as found in Angus, Blonde d’Aquitaine, Dexter, Limousin, Charolais, and Hereford, among others.
It's important to note that it is the same gene. The likelyhood that Dexter cattle could be polled as a new gene mutation, that was exactly the same as the gene that causes pollednes in the other British breeds is beyond calculation. The gene that causes polledness in Dexters tests to be the same as Angus, et al, (Celtic PC) and can be distinguished from Fresian PF. This new information indicates that we can forget about the possibility that there is a third type of polledness unique to Dexters (polled Nonexistum PN).
Kirk: >>Actually, some genes are prone to mutate in certain ways and some mutations are NOT as random and rare as once thought. It's possible that the 2 types of polled mutations found so far have freshly occurred many times in many different breeds. It's sorta like common misspelling of words where lots of folks repeatedly spell a word wrong in exactly the same way. If I misspell a word the same way you misspell a word, it doesn't mean that I copied you.
"There are multiple ways for point mutations to occur. First, ultraviolet(UV) light and higher-frequency light are capable ionizing electrons and in turn impacting DNA. Also, one of the cell metabolic byproducts, reactive oxygen molecules with free radicals, can also be very harmful to DNA. These reactants can lead to both single-stranded DNA breaks and double-stranded DNA breaks. Third, bonds in DNA eventually degrade, which creates another problem to keep the integrity of DNA to a high standard. There can also be replication errors that lead to substitution, insertion, or deletion mutations.
It was previously believed that these mutations happened completely by chance, with no regard for their effects on the organisms. Recently, there have been studies suggesting that these mutations occur in response to environmental challenges. That is to say, they are more likely to occur when they are advantageous to the organism, rather than when they are neutral or disadvantageous. [1]"
Kirk . . all of that is just selective crappy theory. There is so little of even circumstantial evidence to substantiate mutations in the Dexter breed versus introgression it is not even worthy of this repeated attempt to suggest otherwise.
en.wikipedia.org/wiki/Repeat_induced_point-mutation
"Some mutations occur more frequently when they are advantageous than when they confer no advantage. While we generally speak of spontaneous mutations being random, we are also aware that they are not truly distributed at random. There are hot spots for mutations, and some kinds of substitutions occur more often than others".
Kirk, anyone can put anything or change anything on Wikipedia. Puleeze.
Kirk >>http://www.genetics.org/content/126/1/5.full.pdf
Horns are VERY expensive to an animal and primarily useful to fight off LARGE predators. If some horned animals made their way to an island with no large predators, it would be advantageous to be able to eventually eliminate the horns (but it could be useful to hide some recessive horned genes in case the horns were needed again in future generations).
Oh my goodness. This is painful to read.
First and of utmost importance. . . . Dexter cattle are the smallest breed of HORNED European cattle. And they are small in number which makes it easier to change this breed entirely. That would simply be a disaster but it gets closer and closer. Owners and breeders have to decide if they wish to be part of the extinction of a beloved breed whose numbers were so low in recent decades they were on the endangered species list. Think on that! ! Think on species that we have almost lost and preservation efforts have saved them. . . . ( The American Eagle is my favorite).
Would we want the very foundation of our breed to be lost?
The horns are beautiful and rarely threatening and most assuredly manageable. They are not on Dexters only for predator control. . . the designer gave them other important functions as well.
Judy
