8,000 Years Progress = 50 Years Progress

[redfornow]

That would have been a really good feedlot steer, don't you think?

Maybe????

thats true, he had all the heterosis bred out. probably preform less on the lot than a true F1 baldy[/quote]
:nod:

 

[knabe]

Are the four new calves 75% 20X? Also, what percentage does your 107H line bred cow's heifer have of 107H genes?

No, to be 75% 20X, they'd have to be 20X bred back to HIS daughters. They are 37.5% 20X. The cow(dam of the heifer) is 34.375% Enforcer 107H, a maternal granddaughter and traces back to him twice on the top side.(25 + 6.25 + 3.125 = 34.375%). She's a rather average looking cow, but she has really nicked well with my 20X son - producing 4 outstanding heifers and a son that I also used a little before selling him. I'll bet that most of my herd will eventually trace back to her, once I start retaining more bulls and linebreeding.

I haven't figured how much 107H blood is in 20X. But my bull's(20X son) dam is a straight Line 1 cow, so there isn't any Enforcer 107H back there.

George

these are probability numbers, not actual returns on percentage of desirable alleles, elimination of undesirables, and doesn't even take into account accumulated environmental response stored in methylation.

 

[Herefords.US]

these are probability numbers, not actual returns on percentage of desirable alleles, elimination of undesirables, and doesn't even take into account accumulated environmental response stored in methylation.

I'm aware of that. I figured that was understood. Perhaps I'm mistaken when it comes to others understanding it.

George

 

[HerefordSire]

these are probability numbers, not actual returns on percentage of desirable alleles, elimination of undesirables, and doesn't even take into account accumulated environmental response stored in methylation.


Nice input!

I encourage you to post all ye know on the subject so we can learn.

 

[redfornow]

these are probability numbers, not actual returns on percentage of desirable alleles, elimination of undesirables, and doesn't even take into account accumulated environmental response stored in methylation.


Nice input!

I encourage you to post all ye know on the subject so we can learn.

They did! It was almost 2 full lines long....

 

[Herefords.US]

these are probability numbers, not actual returns on percentage of desirable alleles, elimination of undesirables, and doesn't even take into account accumulated environmental response stored in methylation.


Nice input!

I encourage you to post all ye know on the subject so we can learn.

They did! It was almost 2 full lines long....

Actually, knabe was just pointing out that the tradional way that most cattleman refer to pedigrees and the "blood percentage" of ancestors in it is a misnomer. While the probability is good that an animal contains "genes" approximately equivalent to that percentage tracing back to the ancestor, within a couple of standard deviations (especially if close up), the THEORETICAL possiblity actually can range from 0% up to 50% on any ancestors who are not the parents. If an ancestor appears in the pedigree of BOTH parents then the theoretical range of possibility increases to from 0% up to 100%. So, theoretically, by linebreeding cattle with a common ancestor top and bottom, a breeder could end up with a descendant that carries close to 100% of the genes of the common ancestor. One would hope that by selecting for the outstanding traits of a common ancestor and culling against undesirable traits, the next generations will be better than the ancestor.

Outliers can certainly occur and they are often the best or the worst individuals, when judged phenotypically or performance wise. One purpose of linebreeding is to increase the homozygousity of genes in a line of cattle and improve the predictability of what will be produced going forward. Use of an outstanding outlier in a linebreeding program can actually reduce predictability for a generation or two.

My goal, in breeding my herd sire back to a dozen of his daughters, was an effort to make sure there wasn't any simple recessive genes lurking that would cause significant harm in a linebreeding program. A genetic gutcheck before getting too deep into the breeding program. The results should also accentuate the strong points and the faults, making them more evident.

The dwarfism gene that devastated Hereford herds in the 40s and 50s and, most recently, the IE gene are two examples of simple recessive genes.

Luckily, the bovine genome has been mapped and the "offending gene" that causes IE has been identified, including its source where the mutation occurred, and a test was developed so a breeder can just test for its presence.

Such tests weren't available in the 40s and 50s. In the days of dwarfism, the way breeders "proved" that their Hereford herd sires were dwarfism free was to mate them to a dozen or so of their daughters. If a dwarf calf didn't occur in those matings, then the probablity that the herd sire had the dwarfism gene was reduced to virtually zero. The Prospector line of Herefords that later became the foundation of Frank Felton's program was a line that was bred from Hereford cattle containing the dwarf gene. They were linebred to prove that you could successfully breed the dwarfism gene out, by testing for its presence via linebreeding.

The methylation mentioned in knabe's post interests me. I'm interested in knowing how that might affect phenotype and performance variations in closely related individuals.

George

 

[whitecow]

The methylation mentioned in knabe's post interests me. I'm interested in knowing how that might affect phenotype and performance variations in closely related individuals.

George[/quote]


I think knabe's point about methylation was a reference to DNA methylation and epigenetics. There are studies suggesting that environment factors, such as nutrition, can affect DNA methylation patterns. DNA methylation can in turn affect gene expression. Studies in mice have shown that nutritional stress around the time of conception and during gestation can change DNA methylation patterns and cause effects in the offspring that are not predicted by its genotype. DNA methylation patterns are thought to be heritable, but environmantal factors can appearrently cause changes in methylation even in gametes. So, even though the offspring inherits a certain gene from its parent, it might not be expressed because of differences in methylation.

 

[Herefords.US]

I think knabe's point about methylation was a reference to DNA methylation and epigenetics. There are studies suggesting that environment factors, such as nutrition, can affect DNA methylation patterns. DNA methylation can in turn affect gene expression. Studies in mice have shown that nutritional stress around the time of conception and during gestation can change DNA methylation patterns and cause effects in the offspring that are not predicted by its genotype. DNA methylation patterns are thought to be heritable, but environmantal factors can appearrently cause changes in methylation even in gametes. So, even though the offspring inherits a certain gene from its parent, it might not be expressed because of differences in methylation.

So, this could be the reason that some very "average" looking cows are great producers in reality. Their genotype isn't fully expressed in their phenotype?

George

 

[HerefordSire]

Actually, knabe was just pointing out that the tradional way that most cattleman refer to pedigrees and the "blood percentage" of ancestors in it is a misnomer. While the probability is good that an animal contains "genes" approximately equivalent to that percentage tracing back to the ancestor, within a couple of standard deviations (especially if close up), the THEORETICAL possiblity actually can range from 0% up to 50% on any ancestors who are not the parents. If an ancestor appears in the pedigree of BOTH parents then the theoretical range of possibility increases to from 0% up to 100%. So, theoretically, by linebreeding cattle with a common ancestor top and bottom, a breeder could end up with a descendant that carries close to 100% of the genes of the common ancestor. One would hope that by selecting for the outstanding traits of a common ancestor and culling against undesirable traits, the next generations will be better than the ancestor.


I have the understanding if a bovine had 50% of the sire's genes and 50% of the dam's genes, then the specific offspring contained 50% of the genetic material of each parent irregardless of dominancy or recession. Is this not correct? It seems to me one may be responsible for all the dominancy and the other may be responsible for all the recession and still be contributing half of the genetic material as there would still be potential of two recessives meeting together in the future thereby manifesting themselves.

 

[Herefords.US]

I have the understanding if a bovine had 50% of the sire's genes and 50% of the dam's genes, then the specific offspring contained 50% of the genetic material of each parent irregardless of dominancy or recession. Is this not correct? It seems to me one may be responsible for all the dominancy and the other may be responsible for all the recession and still be contributing half of the genetic material as there would still be potential of two recessives meeting together in the future thereby manifesting themselves.

Your point is???? :???:

 

[HerefordSire]

I have the understanding if a bovine had 50% of the sire's genes and 50% of the dam's genes, then the specific offspring contained 50% of the genetic material of each parent irregardless of dominancy or recession. Is this not correct? It seems to me one may be responsible for all the dominancy and the other may be responsible for all the recession and still be contributing half of the genetic material as there would still be potential of two recessives meeting together in the future thereby manifesting themselves.

Your point is???? :???:

I am trying to learn, I guess, as I don't understand completely. Even if I had a theoretical cull calf, the calf would still carry 50% of a theoretical premium sire's genetic material than can be accessed in future generations even if the genetic material of the premium sire were all in a recessive state. Therefore, in referring to a bovine containing 50% of the genes, for example 20X or 107H, is not necessarily incorrect and is not a misnomer. Of course, I am hoping to find my logic in error.

For example, say I had a cull calf sired by Moler. The calf looked very sickly but healthy at the same time. I believe the animal is still very valuable because Moler's genetic material can still be accessed in the next generation and other future generations. Like I said, I am trying to learn and this logic doesn't sound right to me. At what point does genetic material become valueless, or erased, or not possible to be accessed any longer?

 

[Aero]

If your herd needs no improvement then clone away.

so your whole herd is exactly like your best cow?

cloning allows for much easier DNA marker identification.

knowing what you have is a basis of improvement. using "better" young bulls will rarely improve.

a smaller gene pool is the road to consistency.

change is not the same as improvement.

 

[Herefords.US]

I am trying to learn, I guess, as I don't understand completely. Even if I had a theoretical cull calf, the calf would still carry 50% of a theoretical premium sire's genetic material than can be accessed in future generations even if the genetic material of the premium sire were all in a recessive state. Therefore, in referring to a bovine containing 50% of the genes, for example 20X or 107H, is not necessarily incorrect and is not a misnomer. Of course, I am hoping to find my logic in error.

For example, say I had a cull calf sired by Moler. The calf looked very sickly but healthy at the same time. I believe the animal is still very valuable because Moler's genetic material can still be accessed in the next generation and other future generations. Like I said, I am trying to learn and this logic doesn't sound right to me. At what point does genetic material become valueless, or erased, or not possible to be accessed any longer?

I think our problem is that we are talking about two different things.

A calf carries 50% of the genes of each parent. BUT! A calf does not absolutely carry 25% of the genes of each grandparent. Each parent could pass on from 0 to 100% of the genes that it got from EITHER of their parents(the grandparents) and they can only contribute half of the genes to the calf. And the balance comes from the other grandparent. So, for instance, 60% of the genes passed on could come from the parent's sire and only 40% from the parent's dam.

This is where probability comes in. The odds of a parent only passing on 100% of the genes of one of their parents in their sex cell and 0% of the other parent would be much greater than the odds of hitting the lottery. But theoretically, it is possible.

George

 

[Aero]

A calf carries 50% of the genes of each parent. BUT! A calf does not absolutely carry 25% of the genes of each grandparent.

looks like you have been over-clocking your processor too long.

the larger a population is, the more accurate the law of averages is. this is a logarithmic function and after you make it into the thousands of genes, there is little variation from the average. even at the grandparent level, the calf will still inherit pretty much 25% of his 20,000-40,000 genes from each of his grandparents. from my rough estimates, i show well into 99% probability that 24-26% of each grandparents genes will be transfered to the calf.

 

[Herefords.US]

A calf carries 50% of the genes of each parent. BUT! A calf does not absolutely carry 25% of the genes of each grandparent.

looks like you have been over-clocking your processor too long.

the larger a population is, the more accurate the law of averages is. this is a logarithmic function and after you make it into the thousands of genes, there is little variation from the average. even at the grandparent level, the calf will still inherit pretty much 25% of his 20,000-40,000 genes from each of his grandparents. from my rough estimates, i show well into 99% probability that 24-26% of each grandparents genes will be transfered to the calf.

You are correct. I was trying to both simplify and exaggerate the percentages so maybe HS would understand what I was saying - and what knabe was pointing out. HS likes to bet on the "long shot" anyway!

In the grandparent stage, the percentages would not likely vary much, as you have said, but any such variation can be amplified as the generations are pushed further and further back. So when a Remitall calf traces back to 20X seven times in his pedigree and by the commonly used cattle breeder "lingo", he contains 34.375% of 20X "blood", he could vary as much as 10% of that percentage without stretching the law of averages(probability) very far.

George

 

[HerefordSire]

A calf does not absolutely carry 25% of the genes of each grandparent.

This is where I must be missing the boat. That is major stuff. How did I miss that? I reckon I will have to study more just to make sure you are not telling a fiberoni. Thanks for your help.

 

[HerefordSire]

A calf does not absolutely carry 25% of the genes of each grandparent.

This is where I must be missing the boat. That is major stuff. How did I miss that? I reckon I will have to study more just to make sure you are not telling a fiberoni. Thanks for your help.

I should have asked you anther question on my last post:

Is all genetic material either dominant or recessive?

 

[Aero]

A calf does not absolutely carry 25% of the genes of each grandparent.

This is where I must be missing the boat. That is major stuff. How did I miss that? I reckon I will have to study more just to make sure you are not telling a fiberoni. Thanks for your help.

no matter what, a calf gets 25% of its blood from each grandparent. if 2 of the grandparents are the same animal, the calf gets 50% from one animal. dont overthink this.

 

[Herefords.US]

A calf does not absolutely carry 25% of the genes of each grandparent.

This is where I must be missing the boat. That is major stuff. How did I miss that? I reckon I will have to study more just to make sure you are not telling a fiberoni. Thanks for your help.

The key word is absolutely, HS. Think about it, if the selection process was absolute, then all results would be genetically identical.

I was sharing this genetic discussion with our "coffee group" this morning. In that group is a math professor whose specialty is probability and statistics, as well as a couple of biologists.

That discussion clarified my thoughts and I believe I'm correct. All the caveats must be considered. While the law of averages certainly has a bearing on what genes are carried forward, there are a number of genes where homozygosity exists, so it doesn't matter what ancestor(s) contributes them.

In a totally random selection process, the law of averages would also typically tend to balance out any variations....BUT where breeding selections are made based on phenotype and perfomance, that process tends to skew the probability(law of averages), particularly genes in those areas being selected for.

In a linebreeding program, it's really not important that the "blood" percentages are correct...or even close. It's far more important that the desired genes are the ones that's carried forward and homozygosity(whether dominant or recessive) is achieved.

George

 

[HerefordSire]

A calf does not absolutely carry 25% of the genes of each grandparent.

This is where I must be missing the boat. That is major stuff. How did I miss that? I reckon I will have to study more just to make sure you are not telling a fiberoni. Thanks for your help.

no matter what, a calf gets 25% of its blood from each grandparent. if 2 of the grandparents are the same animal, the calf gets 50% from one animal. dont overthink this.

Thanks for the help Aero! What you just wrote is what I have generally thought. Don't you know by now I over-analyze everything so I am non-productable? :mrgreen: