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DNA isn’t everything! While our DNA plays a very large role in how our bodies look and grow, environmental factors play a role too.

Our DNA influences how we grow and develop in the womb. Fingerprints begin to form on a fetus growing in the womb at around 10 weeks gestation and are set before 20 weeks gestation. Some aspects of fingerprint formation are the result of genetic influence. The three main fingerprint patterns (whorls, ridges, and arches) have a genetic component and tend to run in families, so if you have whorls on all your fingers it is likely your brother does too. Your genes don’t directly control the pattern of your fingerprint, rather they control the factors that lead to the formation of the different shapes, such as the symmetry of your fingers.

Because identical twins have the same DNA that controls the formation of their fingers, they have the same main fingerprint patterns. The difference comes in with the ‘minutiae’ of their prints, the small characteristic differences such as where ridges meet, end or join. If it isn’t the DNA that controls this, then what is it?

The minutia of the prints are influenced by environmental factors. In the case of identical twins, the differences may be the result of where in the womb each twin was during development, how close they were to the amniotic sac, the length of their umbilical cord, or access to nutrition! So, the formation of fingerprints is the result of the interaction of our genes and the conditions within the uterus.

The same can be said of many of our physical characteristics. With the example of height, our genes are responsible for a large portion of how tall we may grow, but environmental factors like nutrition, illness, stress, physical activity, and climate also play a role in how tall we end up being. These intricate and complicated interactions between genes and environmental factors play a very important role in human development, but also how plants and animals grow and develop!

You may be interested to read this article from The Conversation if you would like to know more about fingerprints.