Homozygous vs. Heterozygous: Genotype Definitions — Reading Comprehension

Imagine looking at your family. You might notice you have your mother’s eye color or your father’s hair color. How do these traits get passed down? The answer lies in something called genetics, the study of heredity. Every living thing, including you, has a special set of instructions inside its cells. These instructions are called genes. Think of genes as tiny recipe cards that tell your body how to grow and what traits to have.

For each trait, like eye color or hair type, you usually get two copies of a gene – one from your mother and one from your father. These different versions of a gene are called alleles. For example, the gene for eye color might have an allele for blue eyes and an allele for brown eyes. Your unique combination of these alleles is what determines your specific traits.

The specific set of alleles an organism has is called its genotype. This is the genetic makeup you can't always see. What you *can* see, like brown eyes or curly hair, is called the phenotype. The genotype is the internal code, and the phenotype is the observable trait.

Now let's talk about the different kinds of genotypes. If you receive two identical alleles for a particular trait from your parents, you are homozygous for that trait. For instance, if you get an allele for blue eyes from your mother and an allele for blue eyes from your father, you are homozygous for blue eyes. This means your genetic code for that specific trait is uniform.

On the other hand, if you receive two different alleles for a trait – like one allele for brown eyes and one allele for blue eyes – you are heterozygous for that trait. In this case, one allele might be stronger, or dominant, and show up as your phenotype, while the other, recessive, allele is still present in your genotype but doesn't show. Understanding homozygous and heterozygous genotypes helps us predict how traits are passed through generations in all kinds of organisms, from pea plants to people. These fundamental concepts are key to understanding the diversity of life and how we inherit our unique characteristics.

Interesting Fact: Humans share about 99.9% of their genes with each other, with the slight variations in alleles accounting for all our unique differences!

What are the instructions inside cells called?

What is the study of heredity called?

If you have two identical alleles for a trait, you are:

Which term describes the observable traits?

A recessive allele only shows if a person is homozygous for it. This statement is:

What is the definition of an allele?

Why do individuals have two alleles for each trait?

If a person has a genotype of one allele for brown eyes and one for blue eyes, what is their genotype called?

If a plant has a genotype for tallness (TT), and another for shortness (tt), what could be the genotype of their offspring if T is dominant?

A cat has fur with spots, but its parents both had solid-colored fur. This suggests the spotted fur allele is likely: