Genetic Make-up Flashcards
Selection Pressure
environmental factors which determine whether an organism will be more or less successful at surviving and reproducing
Gene Pool
the sum total of all the alleles present in a population at any one time.
Mutation
cause changes in the sequence of DNA, leads to changes of proteins or new alleles
Gene Mutations
affect the base sequence of a single gene
Chromosomal Mutations
changes in the structure of a chromosome involving large pieces being rearranged,
Aneuploidy
loss or gain of whole chromosome
Polyploidy
loss of gain of complete sets of chromosomes
Point Mutations
gene mutations involving a single nucleotide
Missense Substitution
single base substituted by another
Nonsense Substitution
single base substituted by another
Reading Frame Shift by Insertion
single base is inserted, disrupting the reading sequence for all those after.
Partial Reading Frame Shift
single base is inserted and another is deleted at a different location. Causes localised frame shift
Deletion
break occurs at two points on the chromosome and the middle piece falls out, two ends rejoin to form chromosome deficient in some genes
Translocation
movement of a group of genes between different chromosomes. Piece of one breaks off and joins another.
Inversion
middle piece of the chromosome falls and, rotates 180 and rejoins.
Duplication
segment is lost from one chromosome and added to its homologue.
Gene Flow
movement of genes into or out of a population (immigration and emigration)
Genetic Drift
random fluctuations in the frequency of alleles from generation to generation due to chance events
Population Bottlenecks
environmental event that drastically reduces the size of a population
Founder Effect
loss of genetic variation that occurs when a new population is established by a very small number of individuals from a larger population
Natural Selection
process by which populations of living organisms adapt and change, selectively altering genetic variation through differential survival and reproduction
Allopatric Speciation
formation of a new species from pre-existing species, occurring when a geographical barrier physically isolates populations of an ancestral species
Selective Breeding
occurs when man directly intervenes in the breeding of animals to produce desired traits in offspring
