My first question is whether it's possible for two people to have the same biological parents, without being more genetically related to each other, than to any other person.
We spilt mum's 46 chromosomes into part 1 and part 2, with 23 chromosomes in each part, different to any other chromosome of the other part, and do the same with dad's chromosomes as well.
The most likely thing to happen when the parents have a baby is that the baby has chromosomes from both of the parts from the parents. But there's a small chance that the baby has got, for example, it's mum chromosomes from her part 1 only, and it's dad chromosomes from his part 2 only.
Then these parents could have a second baby, which has got it's mum chromosomes from her part 2 only, and it's dad chromosomes from his part 1 only.
If so, these two babies wouldn't be sharing any chromosome. It would of course be working the other way too, with the same chance, that the babies share every chromosome, and thus are as much related to each other as identical twins.
Am I right here, or have I missed something? If I'm right, could anyone please calculate the odds for one of these things happening for two babies with the same parents?
My second question is whether there's an outside chance that a homozygot brown eyed parent and a homozygot blue eyed parent can have a blue eyed baby, which would require that baby to be homozygot blue eyed.
Sometimes something goes wrong when a sperm cell or an egg cell is created. Instead of getting 23 chromosomes, one of them could, for example, get 24. That's why a baby with downs syndrome is born has got 47 chromosomes.
Then I thought the blue eyed homozygot parent could have an extra of the chromosome where the gene for eye colour is located, and the brown eyed
homozygot could be missing the chromosome where the gene for eye colour is located.
Could this lead to a healthy, blue eyed homozygot baby, or would complications occur here due to inbreeding, and do you then think such a baby at least could survive?