In this blog post, we’ll explore how genetic traits, such as double eyelids, are determined through the relationship between DNA and proteins.
Do you have double eyelids? Do you get a lot of acne? Or do you have a body type that gains or loses weight easily? In the heart of bustling downtown areas, dozens of plastic surgery clinics line the streets, and from skin care salons to fitness centers, many people are deeply concerned about their appearance. However, these are merely the results of acquired procedures or personal effort. Some people are born with double eyelids that others do not have, or with smooth, clear skin, or a physique that doesn’t gain weight easily but builds muscle well. Why are some people born with these characteristics, while others are not? We might wonder if human destiny is, to some extent, predetermined at birth.
Do you believe in destiny? Even if you’re not a fatalist, every human being is born with a destiny—or rather, a pre-determined path. Just like the threads woven by the three Fates in Greek and Roman mythology, the information that makes up our bodies is stored in a double-helix molecule called DNA. In other words, the information regarding whether or not we have double eyelids—a feature we’re so interested in—is also encoded within this DNA. Everyone has probably heard the term “DNA” at least once. However, even if people know the name and role of DNA, they often do not fully understand how this “thread of fate” determines an individual’s characteristics and produces traits such as the presence or absence of double eyelids.
Fundamentally, human characteristics are greatly influenced by the types and amounts of proteins produced within the body. In other words, the synthesis of specific proteins—and the quantities produced—determines a person’s various characteristics, and understanding the processes through which proteins are synthesized is key to understanding gene expression. However, double eyelids are known to be a trait resulting from the complex interaction of multiple genes and developmental processes, rather than being determined directly by a single specific protein. Ultimately, the genetic information stored in DNA regulates the production and expression of various proteins, thereby influencing the formation of the eyelid structure.
So, how are the DNA that contains information about double eyelids and the proteins that actually perform the function connected? Simply put, DNA is like a vast blueprint, and proteins are created by linking amino acids in sequence based on the information from the necessary parts of that blueprint. In other words, the necessary genetic information is transmitted from the long DNA chain via RNA, and various proteins are synthesized as amino acids are linked using that information.
DNA is a massive blueprint that stores information. The information within DNA is stored based on the sequence in which four types of nucleotides—adenine (A), thymine (T), guanine (G), and cytosine (C)—are arranged. Genes exist within specific segments of this nucleotide sequence, and based on that information, the necessary proteins are produced and various traits are expressed.
To understand the process by which proteins are synthesized from DNA, we must first understand the characteristics of DNA and nucleotides. Under normal conditions, DNA forms a double helix structure consisting of two complementary strands. Here, “complementary” means that the two DNA strands pair up precisely with each other, just as a key fits into a lock. So how is DNA able to form these complementary bonds?
