| A | B |
|---|
| Multigene trait | When not just one pair of genes, but three or four pairs of genes determines a trait. |
| XY | These are the two sex chromosomes that a male can produce. |
| Heredity | The passing of traits from parents to offspring. |
| Bb | An example of a hybrid gene combination. |
| Mutation | This is caused by any change in a gene or chromosome. |
| Natural Selection | The process by which individuals that are better adapted to their environment are more likely to survive and reproduce. |
| Recessive allele | When paired, this gene will be masked or covered up by a dominant allele. Represented by a lower case letter. |
| Genetic engineering | When genes from one organism are transferred into the DNA of another organism. |
| DNA | This substance makes up genes. It has a shape like a twisted ladder. It can be used to identify a person just like a fingerprint. |
| Dominant allele | When paired, this allele will hide the effect of a recessive allele. It is represented by an upper case letter. |
| Chromosome | Made up of many genes joined together like beads on a string. There are 46 of these in human body cells. |
| Trait | A physical characteristic such as black hair. |
| Selective breeding | The process of selecting a few organisms with desired traits to serve as parents for the next generation. |
| Codominance | When two genes in a pair are different but neither is dominant over the other. |
| BB or bb | An example of a pure gene combination. |
| Gene | A unit of genetic material that determines a trait such as brown eyes. |
