| A | B |
|---|
| allele | Each member of a gene pari/form of a gene |
| blood group | Trait determined by multiple alleles |
| OO | Genotype for type O blood |
| codominant | Pair of alleles that are equally dominant |
| sickle cell anemia | Blood disorder inwhich blood cells are irregularly shaped |
| color blindness | A sex-linked trait |
| sex-linked trait | Trait determined by genes on the sex chromosomes |
| X | Sex chromosome that carries most of the genes |
| hemophilia | Blood disease in which the blood does not clot properly |
| 2 | Number of genes a female must inherit to show a sex-linked trait |
| nondisjunction | Failure of chromosomes to separate during meiosis |
| 21st | Chromosome affected in Down syndrome |
| amniocentesis | Procedure for detecting genetic disorders |
| karyotype | Diagram showing the size, shape and number of chromosomes in an organism |
| fraternal | Twins developed from two separate fertilized eggs |
| XY | Male genotype |
| trisomy | Group of three chromsomes |
| male pattern baldness | Example of a sex influenced trait |
| carrier | Individual with one recessive gene for a trait who does not show the trait |
| SS | Genotype of an individual with sickle cell anemia |
