- Jan 28, 2011
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Well. Technically this is correct but it still relies completely on the law of averages. Ignoring any genetic abnormalities (and if you ignore that the x and y chromosomes are differently sized in humans), you are guaranteed that you share exactly 50% of your genes with your mother and exactly 50% with your father.
This is absolutely not the case with siblings, but merely the statistical norm.
When children are made, it is with relative indifference which 50% come from mom and dad as the chromosomes are put into a blender, swirled about, run over with a lawn-mower, etc before our sex cells are formed. This allows for some very interesting statistical abnormalities. Let's take a very simple example- (You need to assume that a/e, b/f, c/g, and d/h are the same thing, but different letters are used in this example to keep things easy to follow)
Father's genes-
Aa
Bb
Cc
Dd
Mothers genes-
Ee
Ff
Gg
Hh
Remember that you get only one of each pairing of letters when baby is formed, so take the following two children-
Ae ae
BF bF
cg cG
DH Dh
Each one of these children has 50% from each parent and are 50% genetically similar to each other (4 of their 8 "chromosomes" are the same)
But take this scenario-
AE ae
BF bf
CG cg
DH dh
Each one of these children has 50% from each parent and 0% of their genetic information is shared. In this situation you have two children who are absolutely 100% genetically unrelated to each other even though they are both generically related to their mutual parents. And yes, while the numbers are laughably small, THIS CAN HAPPEN (something like a 1 x 10 to the -30 or .0000000000000000000000000000001% chance. Don't quote me. It's somewhere between 10 to the -17 and 10 to the -31)
The opposite can happen as well with the same % chance, you can have kids that are genetically identical twins but born during different pregnancies.
We state that our children are 50% related to each other as a general rule of thumb and a general rule of randomization because, on average, children will be somewhere between 45 and 55% genetically identical due to there being so many different genes that get randomly assorted. But it is not unheard of for some kids to hover at the 30% related to each other as well as 70% related to each other.
We are guaranteed a 50% relation to our parents, a 25% relation to our grandparents, a 12.5% relation to our great grandparents and the same is true when looking at children, grandchildren, etc...
When you breed an animal to a non-sibling relative, you may not be able to know which genes are shared, but you are able to control how MUCH of those genes are shared.
When you breed an animal to a sibling, you are assuming 50% shared but in truth that number could actually be anywhere from all to none.
Didn't really sleep last night as I had to drive my wife to her parents house and we got in around 4am. If I ever find the time to nap I'll re-read this to make sure it makes sense.
Quote:
This is absolutely not the case with siblings, but merely the statistical norm.
When children are made, it is with relative indifference which 50% come from mom and dad as the chromosomes are put into a blender, swirled about, run over with a lawn-mower, etc before our sex cells are formed. This allows for some very interesting statistical abnormalities. Let's take a very simple example- (You need to assume that a/e, b/f, c/g, and d/h are the same thing, but different letters are used in this example to keep things easy to follow)
Father's genes-
Aa
Bb
Cc
Dd
Mothers genes-
Ee
Ff
Gg
Hh
Remember that you get only one of each pairing of letters when baby is formed, so take the following two children-
Ae ae
BF bF
cg cG
DH Dh
Each one of these children has 50% from each parent and are 50% genetically similar to each other (4 of their 8 "chromosomes" are the same)
But take this scenario-
AE ae
BF bf
CG cg
DH dh
Each one of these children has 50% from each parent and 0% of their genetic information is shared. In this situation you have two children who are absolutely 100% genetically unrelated to each other even though they are both generically related to their mutual parents. And yes, while the numbers are laughably small, THIS CAN HAPPEN (something like a 1 x 10 to the -30 or .0000000000000000000000000000001% chance. Don't quote me. It's somewhere between 10 to the -17 and 10 to the -31)
The opposite can happen as well with the same % chance, you can have kids that are genetically identical twins but born during different pregnancies.
We state that our children are 50% related to each other as a general rule of thumb and a general rule of randomization because, on average, children will be somewhere between 45 and 55% genetically identical due to there being so many different genes that get randomly assorted. But it is not unheard of for some kids to hover at the 30% related to each other as well as 70% related to each other.
We are guaranteed a 50% relation to our parents, a 25% relation to our grandparents, a 12.5% relation to our great grandparents and the same is true when looking at children, grandchildren, etc...
When you breed an animal to a non-sibling relative, you may not be able to know which genes are shared, but you are able to control how MUCH of those genes are shared.
When you breed an animal to a sibling, you are assuming 50% shared but in truth that number could actually be anywhere from all to none.
Didn't really sleep last night as I had to drive my wife to her parents house and we got in around 4am. If I ever find the time to nap I'll re-read this to make sure it makes sense.
Quote:
