1.
Alleles: Alternative versions of a gene.
2.
Amniocentesis: A technique in a test that is able to determine if a developing fetus has Tay-Sachs disease.
3.
Character: A heritable feature, such as a flower color.
4.
Chorionic Villus Sampling (CVS): A technique where a physician inserts a narrow tube through the cervix into the uterus and suctions out a tiny sampling of fetal tissue from the placenta.
5.
Codominance: The two alleles affect the phenotype in seperate, distinguishable ways.
6.
Complete Dominance: The phenotypes of the heterozygote and dominant homozygote are indistinguishable.
7.
Cystic Fibrosis: The most common lethal genetic disease in the United States.
8.
Dihybrids: The breeding experiements of two different characteristics.
9.
Dominant Allele: The allele that is fully expressed in the organism's appearance.
10.
Epistasis: A gene at one locus alters the phenotypic expression a gene at a second locus.
11.
F1 Generation: The hybrid offspring.
12.
F2 Generation: The offspring of the self-polinating F1 Generation.
13.
Genotype: An organism's genetic makeup.
14.
Heterozygous: An organism having two different alleles for a gene.
15.
Homozygous: An organism having a pair of identical alleles for a character.
16.
Huntington's Disease: A degenerative disease of the nervous system.
17.
Hybridization: The mating, or crossing, of two true-breeding varieties.
18.
Incomplete Dominance: Where the F1 hybrids have an appearance somewhere in between the phenotypes of the two parental varieties.
19.
Law of Independent Assortment: The independent segregation of each pair of alleles during gamete formation.
20.
Law of Segregation: Mendel's first law, stating that allele pairs seperate during gamete formation, and then randomly re-form as pairs during the fusion of gametes at fertilzation.
21.
Monohybrids: The breeding experiments of a single character.
22.
Multifactorial: Many factors, both genetic and environmental, collectively influence phenotype.
23.
Norm of Reaction: The range of phenotypic possibilites for a single genotype, as influneced by the environment.
24.
P Generation: The true-breeding parents.
25.
Pedigree: The information about a particular trait assembled into a family tree describing the interrelationships of parents and children and children across generations.
26.
Phenotype: An organism's traits
27.
Pleiotropy: The ability of a gene to affect an organism in many ways.
28.
Polygenic Inheritance: An additive effect of two or more genes on a single phenotypic character.
29.
Punnett Square: A diagram used in the study of inheritance to show the results of random fertilization.
30.
Quantitative Characters: A heritable feature in a population that varies continuously as a result of environmental influences and the additive effect of two or more genes (polygenic inheritance).
31.
Recessive Allele: The allele with no noticeable effect on the organism's appearance.
32.
Sickle-Cell Disease: The most common inherited diesease among blacks.
33.
Tay-Sachs Disease: A lethal disorder inherited as a recessive allele.
34.
Testcross: The breeding of a recessive homozygote with an organism of dominant phenotype but unknown genotype.
35.
Trait: Each variant for a character, suc as purple or white color for flowers.
36.
True-Breeding: When plants self-pollinate, all their offspring are of the same variety.
