I learned genetics when I was 5. My mom loved breeding rats to see what kind of babies would come out ant taught me the logic. It's sad and frustrating that others think it's curing cancer, so I'm writing this book to help people understand!
Contain...
So we got the basics down, and we know some vocabulary. Punnet squares are useful when we have only 1 variable, like a dog having up or down ears. But we know there's more than 1 kind of hair color or skin type, so what happens then?
For things like this, there are 2 or more traits within a trait. Let's take human hair color. Hair color is determined by our melanin, of which there are two types: eumelanin and pheomelanin (or black and red color, respectively.) Each of these melanin types has its own trait, so someone can have :
-All red no black (orange hair)
-All black no red (Ashen hair, it looks blue when you pass light through it!)
-No color at all (for albino people only, looks white)**
-Lots of or some of both (Dark brown, brunette, blonde all have a little of both.)
**Footnote: No, old people do NOT have a genetic mutation when their hair gets gray. The body stops making both types of melanin when you get old, so your hair looks white, or maybe gray if you had really dark hair.
As there is more than 1 trait in play, we use two Punnet squares separately to find out what kind of hair color we have.
Changing topics, dogs have red and black and brown hair types. But they have all sorts of blues and lilacs and spotting and stuff (actually, some humans have stripes too!). This is caused by three or more traits and required attention as well.
Take this dog:
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What causes THIS kind of dog?
First off, look at the base. This dog is black and tan, a very dominant type of base coat. We can tell because there's a black nose and a red face.
This dog has black spots though, not a black coat. This is called merle. Merle is a dominant-but-hard-to-get trait which goes on top of the base.
This dog has white spots and a white chest too. This is a trait called 'and white' which is always the last thing to go on the dog.
Now look at these dogs:
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This is a blue dog, but what causes it?
This is a good example of the dilute gene. This gray dog is a dilute black dog. Makes sense, when you think about it.
This dilute gene also applies to brown coats, called lilac. Here's what a lilac dog looks like:
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(Also, this dog is a brown-and-tan, a variation of the black-and-tan.)
