| A | B |
|---|
| trait | characteristic that an organism can pass on to its offspring through its genes |
| heredity | the passing of traits from parents to offspring |
| genetics | scientific study of heredity |
| purebred | alleles are the same |
| 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 if the allele is present |
| recessive allele | an allele that is masked when a dominant allele is present |
| hybrid | 2 different alleles for a trait |
| probability | the likelihood that a particular event will occur |
| punnett square | a chart that shows all the possible combinations of alleles that can result from genetic crosses |
| phenotype | physical appearance |
| genotype | genetic makeup |
| homozygous | having 2 identical alleles for a trait |
| heterozygous | having two different alleles for a trait |
| codominance | neither of the alleles is dominant or recessive |
| meiosis | occurs in sex cells - number of chromosomes is reduced by half |
| multiple alleles | 3 or more forms of a gene that code for a trait - blood type |
| sex-linked gene | carried on the X or Y chromosome |
| pedigree | a chart that tracks which members of a family have a particular trait |
| genetic disorder | an abnormal condition that a person inherits through genes or chromosomes |
| clone | an organism that is genetically identical to the organism from which it was produced |
| genetic engineering | transfer of a gene from the DNA of one organism into another organism to create an organism with desired traits |
| genome | all the DNA in one cell of an organism |
| carrier | one recessive and one dominant allele for a trait but does not have the trait |
| karyotype | a picture of all the chromosomes in a cell |
| gene therapy | putting working copies of a gene into the cells of a person with a genetic disorder in an attempt to correct the disorder |
