Post by Cascade Meadows Farm - Kirk on Dec 1, 2012 18:25:49 GMT -5
Here's an interesting little fact.
Bulls produce about 5 billion sperm per day, and a typical sperm count in a typical mating is often about 10 billion sperm.
Of the 10 billion sperm involved in a typical mating, there are hundreds of thousands or even millions of those sperm with dna copying errors called mutations.
One of the horn regulator genes is thought to have a copy-error-rate of about 1 in 10,000 sperm. So in a batch of 10 billion sperm from a horned bull, there would be 1 MILLION sperm that HAVE the mutant polled gene.
We typically use the word "Carrying" to mean that the bull himself has some hidden genetics in all of his body cells and he can potentially pass those genes to his calves.... But this alternative form of "Carrying" means that some sperm have the trait (via mutations) even though the bull himself does not have the trait in his own body cells.
So, even the most old-time "legacy" horned dexter bulls make MILLIONS of polled sperm each week. Every horned bull has the potential to create polled calves even when bred on horned females.
It's just a matter of time before one of the millions of polled sperm (from a horned bull) wins the race of being the first one to reach an egg in a horned cow. We'll see new fresh polled mutations pop up in Dexters in the future, as they certainly have in the past. The mutations are already there in all sperm, it's just a matter of which sperm reaches the egg first.
PS. The appearance of mutations provides no disproof, nor proof of an animal's parentage. Even DNA parentage tests are NOT 100% perfect (although parentage tests can provide good information and they may be worth doing if you can afford them).
All dexters descend from non-dexters and all pedigrees contain some questionable entries if you go back far enough. None of the old history is provable nor disprovable, so discussing it at length is pointless.
Bulls produce about 5 billion sperm per day, and a typical sperm count in a typical mating is often about 10 billion sperm.
Of the 10 billion sperm involved in a typical mating, there are hundreds of thousands or even millions of those sperm with dna copying errors called mutations.
One of the horn regulator genes is thought to have a copy-error-rate of about 1 in 10,000 sperm. So in a batch of 10 billion sperm from a horned bull, there would be 1 MILLION sperm that HAVE the mutant polled gene.
We typically use the word "Carrying" to mean that the bull himself has some hidden genetics in all of his body cells and he can potentially pass those genes to his calves.... But this alternative form of "Carrying" means that some sperm have the trait (via mutations) even though the bull himself does not have the trait in his own body cells.
So, even the most old-time "legacy" horned dexter bulls make MILLIONS of polled sperm each week. Every horned bull has the potential to create polled calves even when bred on horned females.
It's just a matter of time before one of the millions of polled sperm (from a horned bull) wins the race of being the first one to reach an egg in a horned cow. We'll see new fresh polled mutations pop up in Dexters in the future, as they certainly have in the past. The mutations are already there in all sperm, it's just a matter of which sperm reaches the egg first.
PS. The appearance of mutations provides no disproof, nor proof of an animal's parentage. Even DNA parentage tests are NOT 100% perfect (although parentage tests can provide good information and they may be worth doing if you can afford them).
All dexters descend from non-dexters and all pedigrees contain some questionable entries if you go back far enough. None of the old history is provable nor disprovable, so discussing it at length is pointless.