Glossary of Terms:
- albumen: the white of an egg
- allele: an alternate form of a gene. Varients that occur at
the same locus.
- axial: Located on, around, or in the direction of an axis.
- chromosome: a discrete structure composed of DNA (a
double-stranded molecule that contains genetic code) and protein
found only in the nuclei of cells.
- dominant: a trait governed by an allele that can be expressed
in the presence of another, different allele. Dominant alleles prevent
the expression of recessive alleles in heterozygotes.
- filial: having or assuming the relation of a child or
- genotype: the genetic makeup of an individual; for a
particular trait, you can't always tell the genotype by looking at the
- heterozygotes: organisms with heterozygous genes.
- heterozygous: having different alleles at the same locus on
a chromosome; a recessive and a dominant are paired (so the dominant
trait is observed).
- homozygous: having the same allele at the same locus on
a chromosome; two recessive genes are paired, or two dominant genes
- homozygous dominant: having dominant alleles at the same
locus on a chromosome.
- homozygous recessive: having recessive alleles at the same
locus on a chromosome. This in the only time a recessive trait will
be phenotypically (physically) seen.
- hybrid: offspring of mixed ancestry.
- locus: the portion of a chromosome responsible for the
production of a polypeptide chain (a sequence of amino acids that may
act alone (or in combination) as a functional protein).
- Mendilian traits: traits that are under the influence of one
genetic locus; also called simple traits (the trait is either
one thing or another, there is no 'in between' mixing).
- phenotype: the observable or detectable physical
characteristics of an organism; the detectable expression of the genotype.
- purebred: an organism who, when mated with another purebred
with the same characteristics, will always produce purebreds;
genotypically, purebreds are homozygous.
- recessive: a trait that is not physically expressed in
heterozygotes. In order for the trait to be expressed, there must
be two copies of the allele.
- terminal: growing at the end of a branch or stem.