Amylase facts for kids
Amylase is a special helper molecule, called an enzyme, that your body uses to break down starch. Starch is a type of carbohydrate found in foods like bread, pasta, and potatoes. Amylase turns this starch into smaller sugars, which your body can then easily use for energy.
There are different types of amylase found in many living things, including animals, plants, and fungi. In humans, we have two main types: alpha-amylase and gamma-amylase.
Alpha-amylase is a very important digestive enzyme. You'll find it in your saliva (that's the spit in your mouth!) and in a liquid made by your pancreas called pancreatic juice. This type of amylase works best at a pH level of about 6.7–7.0, which is slightly less acidic than pure water. It starts breaking down starch into smaller pieces, like maltose, right in your mouth and continues in your stomach.
Gamma-amylase works best in more acidic conditions, around a pH of 3. This means it's super active in your stomach, which naturally has a very acidic environment.
How Amylase Changed Humans
It seems that early humans didn't have much amylase in their saliva. Our closest relatives, chimpanzees and bonobos, have very few or no copies of the gene that makes salivary amylase.
But over time, something cool happened! A change in our genes (called a duplication event of the AMY1 gene) led to humans being able to produce amylase in their saliva. This same kind of change also happened on its own in rodents. This shows how important salivary amylase is for animals that eat a lot of starchy foods.
After the agricultural revolution, humans started growing their own food instead of just hunting and gathering. This meant they ate a lot more plant-based foods, which are rich in carbohydrates and starch. Before this, only about 35% of a human's diet was carbohydrates. After farming began, it jumped to about 49%!
Because starch became such a big part of our diet, humans who had amylase in their saliva could digest starch much better and get more energy from it. This was a big advantage!
Not everyone has the same number of copies of the AMY1 gene. People who come from groups that traditionally ate a lot of starchy foods tend to have more copies of this gene. For example, people from European-American and Japanese backgrounds, who eat a lot of starch, might have six copies. But hunter-gatherer groups, like the Biaka, Datog, and Yakuts, who eat less starch, might only have 2-3 copies.
This connection between how much starch people eat and how many AMY1 gene copies they have suggests that natural selection played a role. Natural selection means that traits that help a living thing survive and have healthy babies become more common over time. So, having more AMY1 copies was a helpful trait for people eating lots of starch. It likely made them healthier and stronger, allowing them to have more healthy offspring. This is strong evidence that natural selection has shaped this gene in humans.
See also
In Spanish: Amilasa para niños
