Alleles Definition — Reading Comprehension

Imagine looking around your classroom. You'll notice everyone has unique features! Some friends might have curly hair, while others have straight hair. Some have brown eyes, and others have blue or green. What makes us all so different, even though we are all human? The answer lies in something tiny inside our bodies called genes.

Genes are like instruction manuals for your body. They carry the information that determines your traits, which are the specific characteristics you have. For example, there's a gene that gives instructions for hair color, another for eye color, and many more for everything from your height to whether you can roll your tongue.

But here's where it gets interesting: these instruction manuals aren't always exactly the same. Different versions of the same gene exist. These different versions are called alleles. Think of it like a recipe for a cake. The basic recipe is for 'cake' (the gene), but there can be different versions of that recipe – one for chocolate cake, one for vanilla cake, and one for strawberry cake. Each of these different cake recipes is like an allele.

So, for the hair color gene, there might be an allele for brown hair, an allele for blonde hair, or an allele for red hair. For the eye color gene, there could be an allele for blue eyes and an allele for brown eyes. You inherit one allele for each gene from your mother and one allele from your father. These two alleles together determine your specific trait. For instance, if you inherit a brown eye allele from one parent and a blue eye allele from the other, your body will follow the instructions from both. Sometimes, one allele is 'dominant' and its instructions are followed more strongly, masking the other 'recessive' allele. This is why you might have brown eyes even if you inherited a blue eye allele.

Alleles are incredibly important because they are the reason for all the variations we see in living things. They explain why siblings can look different from each other, why some dogs have floppy ears and others have pointed ears, and why some plants have red flowers and others have white. Understanding alleles helps us understand heredity, which is how traits are passed down from parents to their offspring. It's a fundamental part of genetics, the study of how traits are inherited.

Interesting Fact: Humans and chimpanzees share about 98% of their genes, but the tiny differences in their alleles account for the vast differences between the two species!

What do genes carry?

From whom do you inherit alleles?

Alleles are different versions of what?

Why are alleles important for living things?

What does 'heredity' explain?

If one allele is 'dominant,' what does it do?

The study of how traits are inherited is called genetics. True or False?

Which scenario demonstrates an allele variation?

How do different alleles for a gene create variation in traits, like hair color?

What is the best definition for 'trait' as used in the passage?