genetic diversity Flashcards
(24 cards)
What is genetic diversity?
The number of different alleles in a population
What is genetic diversity caused by?
Gene mutations, meiosis, random fusion of gametes during fertilisation, chromosome mutation
What is genetic diversity acted upon by?
Natural selection
What are gene mutations?
Changes in the sequence of nucleotide bases
When do gene mutations occur?
Spontaneously
Which process could gene mutation occur in?
DNA replication
What is the mutation rate increased by?
Mutagenic agents
What are some examples of mutagenic agents?
X-rays, benzene
What can mutations result in?
Different amino acid sequence in the encoded polypeptide
What is this due to?
Altered base sequence coding for a different sequence of amino acid
Why do not all mutations result in a different sequence of amino acids?
Degeneracy
What is frame shift?
Alteration of the base sequence after the mutation
What are the 6 types of mutation?
Substitution, deletion, addition, inversion, translocation, duplication
What is substitution?
Replacement of one or more bases by one or more different bases
What could substitution result in?
A new amino acid for a non-functioning protein, one different amino acid but still a functioning protein, the same amino acid due to degeneracy so protein remains the same
What is deletion?
The removal of one or more bases
What does deletion result in?
Frame shift so nearly always results in a non-functioning protein
What is addition?
The adding of one or more bases
What does addition result in?
Frame shift so the sequence of amino acids is altered resulting in a non-functioning protein
What is duplication?
Where one or more bases is repeated
What does duplication result in?
Frame shift
What is inversion?
Where the sequence of bases is reversed
What is translocation?
Where a sequence of bases is moved from one location of DNA to another part of the genome
Why do alleles arise?
Alleles arise due to mutations of a gene.
