Blue Eyed Genetics
Blue eyes are found most commonly in Nigerian Dwarfs or Nigerian Dwarf crosses. Blue eyes are dominant in goats, so if one parent has blue eyes, then there is a good chance that he can produce blue-eyed babies. Let's explore the genetics of blue eyed goats. As you know, each goat has two parents, a dam and a sire. For these examples, a brown eyed gene will be identified as b, and a blue-eyed gene will be identified as B.
First, a little explanation of terms:
Each parent gives ONE gene for eye color to each kid, either a brown gene (b) or a blue gene (B).
Heterozygous- A goat that has blue eyes, but she inherited one b gene and one B gene from her parents.
Homozygous- A goat has blue eyes, and she inherited a B gene from both of her parents, who were also both blue eyed.
Since blue eyes are a dominant trait, if a goat has BROWN EYES, then you can assume that the goat has bb eye color genetics. If a goat has blue eyes, then they can be heterozygous for blue eyes (Bb) or homozygous for blue eyes (BB) based upon which genes they received from their parents.
For our first example, let's say that you have a doe who is brown eyed (bb), and she is crossed with a buck who is heterozygous for blue eyes (Bb). When we apply these genes to a grid, you can quickly see the results.
b b
B Bb Bb
b bb bb
In the above case, a brown eyed doe is bred with a buck who is heterozygous for blue eyes. In two cases, the baby with end up with brown eyes, and in two cases the baby ends up with blue eyes. This does not mean that 50% of the babies will have brown eyes, and 50% of the babies will have blue eyes. It means that EACH BABY has a 50% chance of having blue eyes in this case and they will all be heterozygous (Bb) for blue eyes.
Now, lets breed a heterozygous doe, with a homozygous buck.
b B
B Bb BB
B Bb BB
In the above case, all babies will be blue eyed, but EACH BABY has a 50% chance of being homozygous (BB) and EACH BABY has a 50% chance of being heterozygous (Bb) for blue eyes.
In the final case, we will breed a heterozygous (Bb) doe with a heterozygous (Bb) buck.
B b
B BB Bb
b Bb bb
You will notice that this case, the breedings result in heterozygous blue at a rate of 50%, homozygous blue at a rate of 25% and brown eyed babies at a rate of 25%. Again, this DOES NOT MEAN that 75% of the babies born will have blue eyes, it means that EACH baby has a 75% chance of having blue eyes. In a litter from this example, you could have 100% blue eyed babies, or 100% brown eyed babies.
Polled Genetics
Polled means naturally hornless. The genetic example of polled vs. horned goats works very similarly to the blue eyed vs brown eyes example above. The polled gene, like the blue eyed gene, is dominant in goats. We will use the P to represent a polled gene, and an h to represent a horned gene. Again, each parent gives ONE GENE to each kid. Just like the blue eyed genetics, here are also heterozygous (Ph) and homozygous (PP) horn genetics.
WARNING: It has been shown through research, that breeding a polled doe to a polled buck which results in a PP (Polled X Polled) genetic marker will result in the kid having a higher incidence of intersex or hermaphroditic characteristics. For the purpose of these genetic exercises, we will show the results of these breedings, but it is not recommended.
For the first example, let's breed a heterozygous doe to a horned buck.
P h
h Ph hh
h Ph hh
In the above case, each kid has a 50% chance of being polled, and a 50% chance of being horned, with NO INCIDENCE of homozygous polled genetics.
Now let's breed a horned doe with a homozygous buck.
h h
P Ph Ph
P Ph Ph
Because polled genes are dominant, all kids will be polled, but none of them will be homozygous for polled genetics.
Finally, let's breed a homozygous doe with a homozygous buck.
P P
P PP PP
P PP PP
In the final case above, all kids will be polled and homozygous for polled genetics.
Blue eyes are found most commonly in Nigerian Dwarfs or Nigerian Dwarf crosses. Blue eyes are dominant in goats, so if one parent has blue eyes, then there is a good chance that he can produce blue-eyed babies. Let's explore the genetics of blue eyed goats. As you know, each goat has two parents, a dam and a sire. For these examples, a brown eyed gene will be identified as b, and a blue-eyed gene will be identified as B.
First, a little explanation of terms:
Each parent gives ONE gene for eye color to each kid, either a brown gene (b) or a blue gene (B).
Heterozygous- A goat that has blue eyes, but she inherited one b gene and one B gene from her parents.
Homozygous- A goat has blue eyes, and she inherited a B gene from both of her parents, who were also both blue eyed.
Since blue eyes are a dominant trait, if a goat has BROWN EYES, then you can assume that the goat has bb eye color genetics. If a goat has blue eyes, then they can be heterozygous for blue eyes (Bb) or homozygous for blue eyes (BB) based upon which genes they received from their parents.
For our first example, let's say that you have a doe who is brown eyed (bb), and she is crossed with a buck who is heterozygous for blue eyes (Bb). When we apply these genes to a grid, you can quickly see the results.
b b
B Bb Bb
b bb bb
In the above case, a brown eyed doe is bred with a buck who is heterozygous for blue eyes. In two cases, the baby with end up with brown eyes, and in two cases the baby ends up with blue eyes. This does not mean that 50% of the babies will have brown eyes, and 50% of the babies will have blue eyes. It means that EACH BABY has a 50% chance of having blue eyes in this case and they will all be heterozygous (Bb) for blue eyes.
Now, lets breed a heterozygous doe, with a homozygous buck.
b B
B Bb BB
B Bb BB
In the above case, all babies will be blue eyed, but EACH BABY has a 50% chance of being homozygous (BB) and EACH BABY has a 50% chance of being heterozygous (Bb) for blue eyes.
In the final case, we will breed a heterozygous (Bb) doe with a heterozygous (Bb) buck.
B b
B BB Bb
b Bb bb
You will notice that this case, the breedings result in heterozygous blue at a rate of 50%, homozygous blue at a rate of 25% and brown eyed babies at a rate of 25%. Again, this DOES NOT MEAN that 75% of the babies born will have blue eyes, it means that EACH baby has a 75% chance of having blue eyes. In a litter from this example, you could have 100% blue eyed babies, or 100% brown eyed babies.
Polled Genetics
Polled means naturally hornless. The genetic example of polled vs. horned goats works very similarly to the blue eyed vs brown eyes example above. The polled gene, like the blue eyed gene, is dominant in goats. We will use the P to represent a polled gene, and an h to represent a horned gene. Again, each parent gives ONE GENE to each kid. Just like the blue eyed genetics, here are also heterozygous (Ph) and homozygous (PP) horn genetics.
WARNING: It has been shown through research, that breeding a polled doe to a polled buck which results in a PP (Polled X Polled) genetic marker will result in the kid having a higher incidence of intersex or hermaphroditic characteristics. For the purpose of these genetic exercises, we will show the results of these breedings, but it is not recommended.
For the first example, let's breed a heterozygous doe to a horned buck.
P h
h Ph hh
h Ph hh
In the above case, each kid has a 50% chance of being polled, and a 50% chance of being horned, with NO INCIDENCE of homozygous polled genetics.
Now let's breed a horned doe with a homozygous buck.
h h
P Ph Ph
P Ph Ph
Because polled genes are dominant, all kids will be polled, but none of them will be homozygous for polled genetics.
Finally, let's breed a homozygous doe with a homozygous buck.
P P
P PP PP
P PP PP
In the final case above, all kids will be polled and homozygous for polled genetics.
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