| A | B |
|---|
| alleles | alternative versions of a gene that produce distinguishable phenotypic effects |
| amniocentesis | diagnosis uses amniotic fluid to detect certain genetic and congenital defects |
| carrier | heterozygote at a given genetic locus |
| character | observable heritable feature |
| chorionic villus sampling (CVS) | diagnosis uses a sample of the fetal placenta to detect certain genetic and congenital defects |
| codominance | phenotypes of both alleles are exhibited in the heterozygote |
| complete dominance | phenotypes of the heterozygote and dominant homozygote are indistinguishable |
| cystic fibrosis | disorder caused by a recessive allele for a chloride channel protein |
| dihybrid | heterozygous with respect to two genes of interest |
| dominant allele | allele that is fully expressed in the phenotype of a heterozygote |
| epistasis | interaction in which one gene alters the effects of another that is independently inherited |
| F1 generation | first filial |
| F2 generation | offspring resulting from interbreeding of the hybrid F1 generation |
| genotype | genetic makeup, or set of alleles, of an organism |
| heterozygous | two different alleles for a given gene |
| homozygous | two identical alleles for a given gene |
| Huntington’s disease | dominant allele disease with degeneration of the nervous system usually fatal 10 to 20 years |
| hybridization | the mating |
| incomplete dominance | phenotype of heterozygotes is intermediate between the phenotypes of individuals homozygous for either allele |
| law of independent assortment | pair of alleles segregates independently during gamete formation |
| law of segregation | each allele in a pair separates into a different gamete during gamete formation. |
| monohybrid | heterozygous with respect to a single gene of interest |
| multifactorial | influenced by multiple genes and environmental factors. |
| norm of reaction | range of phenotypes produced by a single genotype |
| P generation | parent individuals from which offspring are derived |
| pedigree | diagram of a family tree showing the occurrence of heritable characters |
| phenotype | physical and physiological traits of an organism |
| pleiotropy | ability of a single gene to have multiple effects |
| polygenic inheritance | additive effect of two or more gene loci on a single phenotypic character |
| Punnett square | diagram used in the study of inheritance to show the results of random fertilization |
| quantitative character | heritable feature that varies continuously over a range rather than in an either-or fashion |
| recessive allele | phenotypic effect is not observed in a heterozygote |
| sickle-cell disease | recessive allele that results in the substitution of a single amino acid in the hemoglobin protein |
| Tay-Sachs disease | recessive allele for a dysfunctional enzyme |
| testcross | unknown genotype with a homozygous recessive individual to determine the unknown genotype |
| trait | detectable variation in a genetic character |
| true-breeding | plants that produce offspring of the same variety when they self-pollinate |
