My sister married my husband's brother (so we have two brothers who married two sisters).We are all curious about how related our children will be.If no - can you tell us exactly how related they will be?
Occasionally, it makes a mistake that is not fixed.
Our DNA also changes in response to things like sunlight or the food we eat.
This wasn't as easy to figure out as it might seem...
First off, no DNA can pass through a generation unscathed. For example, we all start out with a single cell and end up with somewhere around 50 or 100 trillion cells.
Even if your sister and you were identical twins, there would be at least 100 differences between her and your DNA. Most of these DNA changes are harmless although some can lead to diseases like cancer. The DNA in all of these cells needed to be copied (not 100 trillion times but a lot).
The machinery in our cells that copies our DNA is incredibly good at what it does, but not perfect.
Both can damage the DNA causing mistakes to happen.
If any of these changes happen in an egg or sperm cell, then that change will be passed on.
(I'm pregnant with our first child right now.) I understand siblings share 50% of the same genes.
In our case would the first cousins be as genetically related as siblings?
This would mean you and your sister's kids would be just a bit different.