Corn Breeding: Introduction to Concepts in Quantitative Genetics Glossary

cross

The deliberate mating of two parental types of organisms in genetic analysis.

DNA

(deoxyribonucleic acid) The molecule that encodes genetic information. DNA is a double-stranded molecule held together by weak bonds between base pairs of nucleotides. It is the fundamental substance of which genes are composed.

environment

The combinations of all the conditions external to the genome that potentially affect gene expression.

gene

The fundamental unit of heredity that carries genetic information from one generation to the next. A gene is an ordered sequence of nucleotides located on a particular position on a particular chromosome that encodes a specific functional protein.

genes

The fundamental unit of heredity that carries genetic information from one generation to the next. A gene is an ordered sequence of nucleotides located on a particular position on a particular chromosome that encodes a specific functional protein.

genotype

The allelic composition of a cell or organism.

genotypes

The allelic composition of cells or organisms.

heritability

The proportion of observed variability which is due to heredity, the remainder being due to environmental causes. More strictly, the proportion of observed variability due to the additive effects of genes.

hybrid

An individual produced by crossing two parents of different genotypes.

phenotype

The observable physical characteristics of an organism that are determined by a combination of the genetic composition (genotype) and the environment of the individual.

protein

A large molecule composed of one or more chains of amino acids in a specific order. Proteins are necessary for the structure, function, and regulation of an organism's cells, tissues, and organs. Each protein has a unique function determined by its shape.

selection

A natural or artificial process that favors or induces survival and perpetuation of one kind of organism over others that die or fail to produce offspring.

trait

The characteristic that results from an expressing gene(s). Ex. Upright leaves, drought tolerance, Bt resistance. A trait can be influenced by the environment.

variety

Crop plants within a species that have the same genetic composition. Because plants in a variety are usually heterozygous, their offspring will not remain genetically pure (i.e., corn hybrid varieties).