inheritance Flashcards
Allele
An allele is one of the different forms of a gene. Alleles of the same gene occupy the same relative positions/gene loci on a pair of homologous chromosomes. Alleles of the same gene have different expressions of the same trait.
Dominant allele
An allele that expresses itself in the phenotype in both homozygous and heterozygous conditions
Recessive allele
An allele that only expresses itself in the phenotype in the homozygous condition
Codominance
A condition where both alleles express themselves in the phenotype
Homozygous
An organism that has identical alleles for a particular phenotype/trait
Heterozygous
An organism that has different alleles for a particular phenotype/trait
Phenotype
The expressed trait in an organism
Genotype
The genetic make-up of an organism
Mutation
A sudden or spontaneous change in gene structure or chromosome number
Variation
Variation refers to differences in a particular trait between individuals of the same species
Discontinuous variation
Discontinuous variation refers to traits that show distinct phenotypes. It is usually controlled by only one or a few genes and is not affected by the environment.
Continuous variation
Continuous variation refers to traits with phenotypes ranging from one extreme to the other. It is brought about by combined (or additive) effects of many genes and is affected by environmental conditions
Natural selection
Natural selection is a process in nature, which results in the best-adapted organisms in a population surviving to reproduce and pass on their genes to the next generation
Artificial selection
Artificial selection is a method used by humans to produce plants and animals with desirable qualities
