| A | B |
|---|
| trait | the characteristic that an organism can pass on to its offspring through its genes |
| heredity | A passing of traits from parents to offspring. |
| genetics | The scientific study of heredity. |
| purebred | An organism that always produces offspring with the same form of a trait as the parent. |
| gene | A segment of DNA on a chromosome that codes for a specific trait. |
| allele | The different forms of a gene |
| dominant allele | An allele whose trait always shows up in the organism when the allele is present. |
| recessive allele | An allele that is masked when a dominant allele is present. |
| hybrid | An organism that has two different alleles for a trait; an organisms that is heterozygous for a particular trait. |
| probability | The liklihood that a particular event will occur. |
| Punnett square | A chart that shows all the possible combinations of alleles that can result from a genetic cross. |
| phenotype | An organism's physical appearance or visible traits. |
| genotype | An organism's genetic makeup or allele combinations. |
| homozygous | same |
| codominance | A condition in which neither of two alleles of a gene is dominant or recessive. |
| sperm | male |
| egg | female |
| meiosis | splitting cell |
| Messenger RNA | RNA that copies the coded message from DNA in the nucleus and carries the message into the cytoplasm. |
| transfer RNA | RNA in cytoplams that carries an amino acid to the ribosome and adds teh growing protein chain. |
| mutation | A change in the gene or chromosome. |
| multiple alleles | Three or more forms of a gene code for a single trait. |
| sex-linked genes | A gene that is carried on the X or Y chromosome. |
| carrier | A person who has one recessive allele for a trait and one dominant allele, but does not have the trait. |
| pedigree | A chart or "family tree" that tracks which members of a family have a particular trait. |
| genetic disorder | An abnormal condition that a person inherits through genes or chromosomes. |
| amniocentesis | A technique by which small amount of fluid that surrounds a developing baby is removed and analyzed to determine whether the baby will have a genetic disorder. |
| karyotype | A picture of all the chromosomes in a cell arranged in pairs. |
| selective breeding | The process of selecting a few organisms with desired traits to serve as parents of the next generation. |
| inbreeding | A selective breeding method in which two individuals with identical or similar sets of alleles are crossed. |
| hybridization | A selective breeding method in which two genetically different individuals are crossed. |
| clone | An organism that is genetically identical to the organism from which it was produced. |
| genetic engineering | The transfer of a gene from the DNA of one organism into another organism in order to produce an organism with desired traits. |
| gene therapy | The insertion of working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder. |
| genome | genome |
