The second trick is: not all genes are the same all of the time. If they were, then all life on Earth would be exact clones of each other. There are variations within individuals. Within a species, the variations are not really "how many strings of beads (chromosomes) they have" as much as "the second bead on string 14 is blue instead of yellow." Which is why members of the same species are so similar, but can still be very different from each other.
Say at some place on chromosome #1 (in the human blueprint) there's a gene that normally produces a vital component for making Melanin (the black/brown/yellow pigment in humans, and in cornsnakes. And actually, just for trivia's sake, almost every known form of life on Earth produces melanin.
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This "Melanin" gene could be altered ("mutated") and so there would be another version ("allele") in some humans that doesn't contribute that vital component for making melanin.
Say you got that gene from one of your parents. But the thing is, you also got the "normal" gene from the other parent, and thus you're still able to produce pigment. The "normal" gene is not stopped from producing melanin, so you can't tell you're a "carrier" of that gene.
The "broken, non-functional" gene is not "expressed." Instead, it is masked by the normal gene. You could say that you are "het for albino" because the gene pair is not a matched pair.
You can also say--since this "albino" gene is not expressed when it is paired up with the "normal" gene--that the "albino" gene is "recessive" to its normal counterpart.
Note that "het" doesn't always mean "there's a hidden gene." It just happens in this case that it is hidden, only because it is recessive. Remember, "het" truly means "the paired genes are different."
Notice that half of your kids (since they inherit one complete set of human blueprint from you) would also inherit that gene. And with those kids' kids, half of them would also be "hets." The gene can be carried through generations and generations without ever being noticed. It wouldn't be noticed because it's a recessive gene.
BUT, if you (being "het") were to have kids with someone who is also "het for albino" (a pair made up of one normal and one albino gene) then there's a chance with each of your kids that they could inherit the "albino" gene from you, and also the "albino" gene from their mother.
In that case, that individual will not have a working copy of all the genes needed to make melanin, so his body will not produce melanin. He would be an albino.
You would also know, since he's actually expressing the "albino" trait (and since you know it's a recessive trait) that he has the gene pair "albino and albino." (This is known as "homozygous for albino," as compared to "het for albino.")
From that, you can also go on to say that:
-If he has any "normal-looking" kids, that they would also be "het for albino." Why? Because he cannot pass down the "normal" gene to them, he's going to give them one of his two copies of the "albino" gene. So they're pretty much guaranteed to be het for albino.
-If he marries another albino and they have kids together, all of their kids will inherit an "albino" gene from each parent. Thus, all of their kids would be albinos, too, because they won't get the "normal" gene from anywhere.