Beginner's Genetics

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randiliana

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Genetics are a hobby of mine. Since the first time I started to learn about them in high school Biology they have interested me. Now, I can experiment with them in our cow herd. I have done quite a bit of research on the internet, but haven't found anything that is comprehensive and easy to understand as far as the basics of genetics in cattle goes. By basics, I mean coat colors and patterns, horns and the other "easy" ones. As far as production, I just don't have the knowledge and tools to try to explain how they work :lol2:

Anyways, I put together a blog to try and explain it to anyone interested. I included a lot of pictures to hopefully make it a little easier to understand, and see what I am talking about.

http://easygenes.blogspot.com/
 
randiliana":1me3c4vh said:
Genetics are a hobby of mine. Since the first time I started to learn about them in high school Biology they have interested me. Now, I can experiment with them in our cow herd. I have done quite a bit of research on the internet, but haven't found anything that is comprehensive and easy to understand as far as the basics of genetics in cattle goes. By basics, I mean coat colors and patterns, horns and the other "easy" ones. As far as production, I just don't have the knowledge and tools to try to explain how they work :lol2:

Anyways, I put together a blog to try and explain it to anyone interested. I included a lot of pictures to hopefully make it a little easier to understand, and see what I am talking about.

http://easygenes.blogspot.com/

The problem is that colors other then red and black are really strange and not well understood by anyone. When you start thowing in patterns the water really gets murky. Horns are straight forward until you throw in the African gene, that's the only "modifier" for horns that I'm aware of. Why it's called the African gene is beyond me since it stems as far as I've ever been able to figure out, from Bos Indicus.
 
Actually, since there are only 3 base colors it isn't that hard to understand. Once you get your mind wrapped around how genes work things come together nicely. The expression of all the colors and patterns I have discussed are controlled by just a couple genes each. Once you know which is dominant and which is recessive you can start to SEE what is in your cows. Look at how Black/Red works, and everything else pretty much works the same. The easy ones are the Incompletely dominant ones, as if there is one copy there you can see it. They don't hide, and you can make a pretty good guesstimate on whether there is only 1 copy or if the animal is homo for the gene.

The other big thing to remember is that there IS only 3 base colors, every other color or pattern is because of another set of genes working on top of the base color, and most of the patterns can work with each other.

So if you have a tan roan white faced animal for example, you can say that the animal is ee(red) Rr (roan) Dcdc(dilution) ShS(whitefaced/solid). There are other genes in there that restrict how much the animal is diluted, and how much white is on the animal, but the ee Rr Dcdc ShS is the basic. And, it is visible.
 
The African horned gene, is, from what I have read, a totally separate gene from the one in the Bos Taurus cattle. I haven't read a lot on it, but I believe it has nothing to do with the horn gene in Bos tarus. Although, it can be found in crossbreds which is where the confusion comes from.
 
randiliana":bl4j99o7 said:
The African horned gene, is, from what I have read, a totally separate gene from the one in the Bos Taurus cattle. I haven't read a lot on it, but I believe it has nothing to do with the horn gene in Bos tarus. Although, it can be found in crossbreds which is where the confusion comes from.

I knowm but why is it called the African gene Af I think when it's from Bos Indicus.
 
Susie David":11bmw4m9 said:
I got lost shortly after the lecture on why cousins can't marry. DMc

Depends on the state. My wifes parents are first cousins, worked ok for them. Those ectra couple of fingers come in handy.
 
dun":2hg6f9pj said:
I knowm but why is it called the African gene Af I think when it's from Bos Indicus.

Who knows, could be the guy that figured it out was from Africa. Or the cattle they were studying were from Africa. I believe that there are a lot of Bos Indicus cattle in Africa. Bramahn aren't the only Bos Indicus cattle out there.
 
I just read an article on cousins having kids it said 4th or 5th cousins are ideal. It said no relation or extremely distant relations are more likely to have problems then cousins of a little distance.
 
randiliana":z8s4ow27 said:
The African horned gene, is, from what I have read, a totally separate gene from the one in the Bos Taurus cattle. I haven't read a lot on it, but I believe it has nothing to do with the horn gene in Bos tarus. Although, it can be found in crossbred which is where the confusion comes from.
Does the horned gene have something to do with color?
I you breed a grey brahman to a red brahman you get a darker grey brahman, sometimes black. They may show some red but generally dark grey. When they are born the calves will usually be red an turn color during the first year.
 
novatech":2lb65yq3 said:
Does the horned gene have something to do with color?
I you breed a grey brahman to a red brahman you get a darker grey brahman, sometimes black. They may show some red but generally dark grey. When they are born the calves will usually be red an turn color during the first year.


The horn gene has nothing to do with color.

There are 2 different genes that can give you horns. The one in Bos taurus cattle, it is recessive to the gene for polledness. And works the same way in males AND females
PP - Homo polled
Pp - Hetero polled (carries the horn gene)
pp - Homo horned (animal is horned)

The one in Bos indicus (brahman and zebu cattle) is called the African horned gene. It is sex linked, in that it only takes one copy for a bull to have horns, and 2 copies for the cow to have horns.

In males
AfAf = homo horned (animal has horns)
AfAn = hetero horned (animal has horns)
AnAn = Homo polled (no horns)

In females
AfAf = Homo horned (animal has horns)
AfAn = Hetero polled (animal is polled but carries the horn gene)
AnAn = Homo polled (no horns)

Simply put, a cow has to be homo to have horns. If you have a horned cow (with the Af gene) then EVERY male calf she has will have horns. However, depending on what she is bred to some, all or none of her heifer calves will have horns.

Also, cattle can carry both kinds of horn gene. They can also carry the scur gene, which is also sex linked in the same way the Af gene is. Sc is dominant in males and recessive in females.

So essentially you COULD have an animal that is AfAf, pp and ScSc, homo for all 3 horn types.
 
novatech":1b1numz4 said:
I you breed a grey brahman to a red brahman you get a darker grey brahman, sometimes black. They may show some red but generally dark grey. When they are born the calves will usually be red an turn color during the first year.

What you are seeing is the Patterned Blackish coloration. It is found in Brahman, Jersey, and Brown Swiss. Bp is dominant to bp, but you can only see it when the animal has a red base color. Adult animals with the Bp look very similar to Wild colored animals, but the males are the same color as females, unlike Wild colored animals where the males are generally darker than the females. The other big difference is that usually Wild colored animals will be born dark, where Bp animals will be born red and turn dark with age.

Bp = Patterned Blackish
bp = normal coloration

Animals must be ee (red) to express the Bp coloration.

BpBp = Homo Blackish
Bpbp = Hetero Blackish
bpbp = normal color

I am thinking that your gray brahma carries the Bp gene, and your red doesn't(or you would see it).
 

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