The National Human Genome Research Institute says that “human beings are 99.9 percent identical in their genetic makeup.” That means that 99.9 percent of your DNA is identical to the DNA of every other person you know—and the other 7.4 billion people you don’t know. Even more amazingly, your DNA is 99 percent identical to chimps and bonobos and 98 percent to gorillas, according to Scientific American.
Of course, there’s a big difference between you and a chimp. And there are big differences between you and the other people you know. You have different color hair and skin, you’re different heights, your eyes are different colors. And then there’s all the things you can’t see, like diseases. That .1 percent makes a big difference. So how can you start to understand it?
One way is to do a survey of your family to explore your inherited traits.
An inherited trait is one that is genetic. It’s determined by your genes, which are passed down from your parents. Think of things like your eye color or the shape of your nose. Inherited traits are different from acquired traits, which you aren’t born with. Think of things like pierced ears or dyed hair.
A variation in one of your genes is called a genotype. Those genotypes can cause a difference in your appearance, which is called a phenotype. But it doesn’t necessarily happen. For one thing, genetic traits may be altered by your environment. For instance, you may inherit the gene for brown hair from your parents, but if you spend all summer playing outside, the sun may turn your hair blond.
But for many things, you can begin to understand your genes by noting the differences in phenotypes. To do that, you can see how your traits—like whether you can roll your tongue or whether you have dimples—compare to your parents’.
Use this online traits survey, developed by Bill Kendrick, to explore your genetic past!
This article is adapted from Exploring Genetics Across the Middle School Science and Math Curricula by Dr. Jeffrey Batten.