Genetic Variation Flashcards
Allele
Any of two or more variants of a gene that have the same relative position on homologous chromosomes which are responsible for alternative characteristics.
Continuous variation
Variation within a species that changes gradually over a range of values.
Diploid
A cell that contains two complete sets of chromosomes, one from each parent.
Discontinuous variation
Variation within a species in which a trait has only a limited number of possible values / groups.
Gamete
A reproductive cell having the haploid (half the number) number of chromosomes, mature egg or sperm.
Gene
A sequence of DNA that occupies a specific location on a chromosome and determines a particular characteristic of an organism.
Genetic variation
Variation in the allele frequency or genome between members of species, or between groups of species.
Haploid
A cell that contains a single set of unpaired chromosomes (e.g. in humans it is 23 unpaired chromosomes).
Locus
The position that a given gene occupies on a chromosome.
Mutagen
An agent, such as a chemical, UV light, or a radioactive element, that can induce or increase the frequency of a mutation in an organism.
Mutation
A permanent change in the base sequence of DNA.
Trait
A genetically determined characteristic or condition.
Somatic cell
Any cell of the body that is not a sexually reproductive cell.
Silent mutation
Mutation that does not change the protein so has no observable effect on an organism.
Neutral Mutation
A mutation that does not harm or benefit the organism.
Beneficial Mutation
A mutation which gives an individual a survival advantage over the other members of its species.
Harmful mutation
A mutation that has a detrimental effect on the organisms fitness (reproduction or survival).
Deletion mutation
Part of the chromosome breaks off reducing the length and removing genes.
Inversion mutation
Rearrangement of the genetic information on the chromosome. Does not affect length of the chromosome.
Translocation mutation
Movement of genetic material from one chromosome to another. Affects the length of the chromosome.
Duplication mutation
Some of the genetic material on the chromosome is copied resulting in the duplication of genes and an increase in its length.
Gene mutations
Affect the arrangement of bases in the genes.
Block mutations (chromosome mutations)
Affect whole genes or the arrangement of genes on the chromosome.
