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Physical Traits in Families

by Flora Richards-Gustafson

“She has your eyes and her father’s nose,” family members ooh and aah. For better or worse, you look like your family. Physical traits passed on by genetics are what makes your little one like you or her other parent or an improved version of both. While many inherited physical traits are plain to see, there are some that require a little digging to find, which can make for a fun family afternoon.

Phenotypic Traits

To understand physical traits, you have to put on your science hat. Physical traits in the science world are called phenotypic trait. To qualify as an inherited phenotypic trait, a feature has to be observable and obvious. So, a family history of heart disease isn't a physical trait, but having curly hair is. To get the physical traits that you and your little one have, biochemical and molecular processes take place that send DNA to RNA and proteins, according to researchers at the University of Utah. This process is like mixing colors. When you mix two paint colors together, the result is a new color that clearly has the two original paints in it. Before your little one was born, the DNA from you and your partner created cells that were released into his tissues and organs. The result is a little bundle of joy with physical traits from both sides of the family.

Examples of Physical Traits

You can easily see many physical traits in your tot's face, hair and hands. Characteristics that qualify as physical traits include hair color and type, attached earlobes, adorable freckles, a dimple in the chin or each squeezable cheek, eye color and hairline (like having a widow's peak or not). Color blindness, being right- or left-handed and the ability to roll your tongue into a tube shape, cross your left thumb over your right when you interlock your fingers or taste the natural chemical phenylthiocarbamide (PTC) also count as physical traits that one generation can pass down to the next.

Environmental Factors

Genetics play a big role in the physical traits that you and your child have, but environmental factors can also make a difference. These factors can include nutrition, pollution, altitude, temperatures and exposure to sunlight. So, for example, if a child has the potential to grow 6 feet tall but is malnourished, there's a chance that he'll never reach that height. Or, if two parents have dark skin and move to an area that isn't very sunny most of the year, their little one may have lighter-colored skin than they.

Physical Trait Activities

The next time you’re at a family gathering, you can do some simple tests to learn more about the physical traits that your family members have in common. The activities are so simple that even your tots can participate. Let all the kids stick out their tongues to see who can roll theirs and do the same test with the parents to see whose genes dominate that trait. A simple, gentle tug on an earlobe will show you if they’re attached or not. Push back everyone’s bangs to see if they have a straight hairline or a widow’s peak. Then gather all of those who hate eating brussel sprouts, cabbage and broccoli for a PTC taste test. Give each person a PTC test strip (you can order them online) and have them place the strip on his tongue. Researchers at the University of Utah state that those who get a look of disgust on their faces and say the test strip tastes bitter have the ability to taste PTC, which is bitter, explaining their hatred of vegetables in the Brassica family.

Photo Credits

  • Ryan McVay/Lifesize/Getty Images