Genetics

the science of heredity.

Allele

alternative form that a single gene may have for a particular trait.

Dominant

Mendel's name for a specific trait that appeared in the F1 generation.

Recessive

Mendel's name for a specific trait hidden or masked in the F1 generation.

Homozygous

organism with two of the same alleles for a specific trait.

Heterozygous

organism with two different alleles for a specific trait.

Genotype

an organism's allele pairs.

Phenotype

observable characteristic that is expressed as a result of an allele pair.

 Law of Segregation

Mendelian law of stating that two alleles for each trait seperate during meiosis.

Hybrid

organism heterozygous for a specific trait.

Law of Independent Assortment

Mendelian law stating that a random distribution of alleles occurs during the formation of gametes.

Genetic Recombination

new combination of genes produced by crossing over and independent assortment.

Carrier

individual heterozygous for a recessive disorder such as cystic fibrosis or Tay-Sachs disease.

Pedigree

diagrammed family history that is used to study inheritance patterns of a trait through several generations and that can be used to predict disorders in future offspring.

Incomplete Dominance

complex inheritance pattern in which the heterozygous phenotype is intermediate between those of two homozygous parent organisms.

Codominance

complex inheritance pattern that occurs when neither allele is dominant and both alleles are expressed.

Multiple Alleles

having more than two alleles for a specific trait.

Sex Chromosome

X or Y chromosomes; paired sex chromosomes determine an individual's gender

Autosome

chromosomes that is not a sex chromosomes.

Sex-linked trait

characteristics such as red-green color blindness controlled by genes on the X chromosome; also called an X linked trait

Polygenic trait

Karyotype

micrograph in which the pairs of homologous chromosomes are arranged in decreasing size.

Test Cross

breeding that can be used to determine an organism's genotype.

Genetic Engineering

technology used to manipulate an organism's  DNA by inserting the DNA of another organism

Gene

 functional unit that controls inherited trait expression that is passed on from one generation to another generation.

Recombinant DNA

newly generated DNA fragment containing exogenous DNA molecules.

Cloning

process in which large numbers of identical recombant DNA molecules are prodeuced.

Mutation

permanent change in a cell's DNA, ranging from changes in a single base pair to deletions of large sections of chromosomes.

Mutagen

substance, such as a chemical, that causes mutations

Genetic Diversity

variety of inheritable characteristics or genes in an interbreeding population.