Genetics and Inheritance — Reading Comprehension Lesson

Reading Passage

Genetics and Inheritance

Have you ever noticed that children often look like their parents? Eye color, hair color, height, and many other characteristics are passed from parents to their children. The study of how traits are inherited is called genetics. Genetics helps scientists understand why living things look and behave the way they do, and why offspring share traits with their parents.

The information for inherited traits is stored in DNA — deoxyribonucleic acid. DNA is a molecule found in the nucleus of almost every cell in the body. It is shaped like a twisted ladder, called a double helix. DNA is organized into sections called genes. Each gene carries the instructions for a specific trait, such as eye color or blood type. Humans have about 20,000 to 25,000 genes.

Genes come in pairs because humans inherit one set of chromosomes from each parent. Each version of a gene is called an allele. Some alleles are dominant — they are expressed whenever they are present. Others are recessive — they are only expressed when two copies of the recessive allele are present. For example, the allele for brown eyes is dominant over the allele for blue eyes.

Gregor Mendel, a 19th-century Austrian monk, is known as the father of genetics. He studied inheritance in pea plants and discovered the basic rules of how traits are passed from one generation to the next. He found that traits are inherited as separate units (which we now call genes) and that some traits mask others. His discoveries formed the foundation of modern genetics.

Genetics affects every living thing on Earth. Understanding genetics has led to advances in medicine, agriculture, and our understanding of evolution. Genetic testing can now identify inherited diseases before symptoms appear. Genetic engineering allows scientists to modify the DNA of organisms. As genetic science continues to advance, it raises important questions about how this powerful knowledge should be used.

Printable Worksheet

More Science Worksheets

Explore our full library of science reading comprehension worksheets and lesson resources.