Allele
Length of DNA on a chromosome normally encoding for
a polypeptide
Gene
The genetic composition of an organism
Genotype
Condition in which the alleles of a particular gene are
different
Heterozygous
A group of genetically identical organisms formed from
a single parent as a result of asexual reproduction or
artificial means
Clone
The number of times an allele occurs within the gene
pool
Allele Frequency
A term applied to cells in which the nucleus contains
two sets of chromosomes
Diploid (2n)
Total number of alleles in a particular population at a
specific time
Gene pool
Condition in which the alleles of a particular gene are
identical
Homozygous
Term used to describe a gene that has more than two
possible alleles
Multiple Alleles
A term applied to an allele that is always expressed in
the phenotype of an organism
Dominant Allele
The characteristics of an organism, often visible,
resulting from both its genotype and the effects of its
environment
Phenotype
A homozygous organism with two dominant alleles
Homozygous Dominant
A change to a phenotype not inherited by future
generations
Modification
The abbreviation for deoxyribose nucleic acid
DNA
Reproductive (sex) cell that fuses with another of the
same type of cell during fertilisation
Gamete
A homozygous organism with two recessive alleles
Homozygous Recessive
The condition in which the effect of an allele is
apparent in the phenotype of a diploid organism only in
the presence of another identical allele
Recessive Allele
A change in the sequence of bases in DNA
Mutation
Term referring to cells that contain only a single copy
of each chromosome
Haploid
Condition in which both alleles for one gene in a
heterozygous organism contribute to the phenotype
Co-dominance
One form of a gene