Study of heredity and variation in living organisms.
In the 1800s, Gregor Mendel experimented with pea plants to understand how traits are passed from parents to offspring. His work laid the foundation for the science of genetics.
Mendel discovered that traits are inherited in predictable patterns. He described two main laws:
Some traits are dominant, meaning they mask the effect of other (recessive) traits. For example, if you inherit one gene for brown eyes (dominant) and one for blue eyes (recessive), your eyes will be brown.
Scientists use Punnett squares to predict the possible traits of offspring based on the genes of the parents.
| B (Brown) | b (Blue) | |
|---|---|---|
| B | BB | Bb |
| b | Bb | bb |
The table above shows the possible genetic combinations when one parent carries a dominant brown-eye gene and a recessive blue-eye gene.
Understanding Mendelian inheritance helps explain why family members look alike, and how certain diseases are inherited.
A child inherits a gene for brown hair from their mother and a gene for blonde hair from their father, resulting in brown hair because brown is dominant.
If both parents carry a recessive gene for a genetic disease, there is a 25% chance their child will inherit the disease.
Mendel's laws explain how traits are inherited in predictable ways through dominant and recessive genes.