Ask A Scientist
Where does my curly hair come from?
Asked by: Jaiden Panella
School: Chenango Bridge Elementary School
Teacher: Ms. Campbell
Hobbies/Interests: Swimming, softball
Career Interest: Spy, rock star
Answer from Lina Begdache
Assistant Professor of Health and Wellness Studies
Research area: Obesity, gastroesophageal reflux disease (GERD), nutrigenomics Interests/hobbies: Running, reading
Your curly hair may be coming from your mom or dad, or even your great-grandma or great-grandpa, though I am sure you are not looking for such an answer! If we use the science of genetics, the answer becomes more elaborate. Genetics is an interesting field that allows individuals to better understand traits and risk for diseases. Let’s explore a few concepts together before I answer your question.
Each cell in the human body contains about 23,000 genes, which carry genetic material known as DNA. DNA is made of four different nucleotides: adenine, thymine, cytosine and guanine. Each gene has a specific long sequence of these nucleotides. DNA is known to be the blueprint of living creatures that gives instructions for development of the organism—its growth, function and traits. These instructions are in the form of proteins.
Genes can also determine the physical characteristics of individuals, like skin, eye and hair colors, and hair type. Genes are not only found in humans, but in animals and plants as well. Because genes are thread-like arrangements of DNA, they are packaged in structures called chromosomes. Each human cell contains two sets of 23 chromosomes. One set comes from mom and the other from dad. Consequently, we carry two copies of almost every gene.
So back to your question, here is a simplified answer. If both of your parents have curly hair, you are more likely to inherit the trait of curly hair. This means that you have received both copies of the curly hair gene from your parents. However, one parent could have straight hair while the other has curly hair. In that case, the dominance (recessiveness) of the gene determines what the hair type of the child is. It could be that neither of your parents have curly hair, but an ancestor did. Then the curly hair gene could have been passed down through generations and your parents are carrier of that gene, which manifested its trait in you!
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