Mutations Flashcards
gene pool
the complete set of alleles present within a particular population
population
a group of individuals of the same species livng in the same location
species
a group of individuals that can interbreed to produce viable and fertile offspring
allele frequenicy
the proportion of certain alleles in a gene pool
what does allele frequency show
it can be used to depict the amount of genetic diversity at the individual, population and species level
genetic diversity
the variation in genetic makeup of alleles within a population
genotype
the genetic composition of an organism at a particular gene locus
phenotype
the physical or biochemical characteristics of an organism that are a result of gene expression ad the environment
what is the cause of phenotypic variation
genotypic variation which results in new alleles being introduced into the gene pool
mutagen
an agent that can cause mutations in DNA
mutation
a random and unpredictable permanent change in genetic information
how can the effects of mutations on the organism be described
advantageous, neutral or deleterious
deleterious
used to describe alleles that have an overall negative effect on individual fitness when expressed
what are the two types of mutations
spantaneous and induced
spantaneous mutations
not caused by any discernable reason
examples of spontaneous mutations
error in DNA repair, error in transcription, error in polymerisation, error in replication
induced mutations
caused by an environmental factor (mmutagen)
types of mutagens causing induced mutations
chemicals radition and UV light (ionising radiation)
examples of chemical mutagens
deaminating agents and base analogous
for a mutation to be heritable
it must occur in an indivduals germline cells, if iit occurs in a somatic cell it is not heritable
where are germline cells located
in the reproductive tissue
what are the two types changes to chromosome number mutations
polyploidy and aneuploidy
polyploidy
when an organism conatins more than 2 copies of each chromosome
triploid
set of chromosomes in groups of three
aneuploidy
when there is an extra or missinh chromosome
what causes aneuploidy
non-disjunctiom during meiosis where homologous chromosomes fail to seperate
trisomy
containing an extra chromosome
monosomy
only having one particular copy of a chromosome
block mutations
chaanges to a large section of DNA or entire gene that involves the alteration of the structure of a chromosome
types of block mutations
deletion, duplication, inversion and translocation
deletion block mutations
removal of a section of DNA
duplication block mutations
replication of a section of DNA, lengthening the DNA/chromosome
inversion block mutations
reversal of section of DNA
translocation block mutations
switching of two sections of DNA on different chromosomes
point mutations
changes to a single nucleotide which can have an effect on the resulting protein
three types of point mutations
base substitution, base deletion and base insertion
three types of base subtituion mutations
silent, nonsense and missense
base insertions and deletions are both
frameshift mutations and therefore missense mutations
silent base subtitution
when a base is changed bbut the same amino acid is produced, can occur due to tthe degenerate nature of the genetic code
nonsense base subtitution
when the base change results in a stop codon, prematurely ends the translation of a genees mrna
missense base subtitution
changes to a bse that result in a different amino acid being produces, alters primary strcture/polypeptide chain
base deletion
type of frameshift mutation and missense, occurs when a base is randomly deleted from the mRNA strand
base insertion
type of frameshift mutation and missense, occurs when a base is randomly added to the mRNA strand
frameshift mutation
mutations that alter the base sequence of a gene so that it no longer makes sense, alters the reading frame of all following nucleotidees
reading frame
the order in which nucleotide triplets or codons are divided into consecutive, non-overlappiiing sequence
