I understand that our chromosomes come from adding the ones in our parents’ sperm and egg cells, but we don’t have the exact chromosomes from our parents gametes, right? But once they combine genetic information, how does that still end up as 2 separate chromosomes?
In: Biology
It’s better to think of it as having 23 pairs of chromosomes.
Half of each pair comes from each parent.
Each of these pairs is a matched set, with only very minor variations between all of humanity.
There’s only about a 0.6% difference between any two human beings alive right now.
There’s a less than 2% difference between us and a chimpanzee, and that’s enough to stop the matching from working.
Both parents pass down 23 chromosomes. Which means you get all 46 chromosomes total from both parents.
Imagine you have a book about all information on how to live your life. Like, how to cook food, how to repair your house etc. And you get a copy of the very same book from both parents.
Now they have their own books from their parents and they also have 2 copies each. But instead of just giving away one, they make a copy personally for you. And they make this copy using both of their own copies. So basically your mom copies, let’s say, pages 1 to 54 from book from her mom’s book, then 55 to 96 from her dad, and so on.
So basically chromosomes are the exact same books. Only that when copying over generations, there are some typos made, and these accumulate on the parental lineages. That’s why when you try to cook a soup from your mom’s version of Life Book, you add twice as much salt. And if you try to fix the tap using your dad’s version of Life Book, you use the wrong type of screw. That’s why luckily you can look it up in the other book.
With chromosomes it means that you have mutations in the genes. But the genes themselves are the same things. Like, the gene for hemoglobin is the same. You have a mom version and a dad version. Maybe they are the exact same thing without typos. But maybe you have a typo from dad or mom that makes you carry anemia.
Having one trait from mom (like eye color) and the other from dad (like ear shape) doesn’t mean that your dad didn’t pass you the eye genes and your mom didn’t pass you the ear genes. It just means that when you were made, the dad version of eye color gene had such a typo that your eyes were cooked up using mom’s recipe. And your ear was cooked using dad’s recipe.
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