Causes and consequences of diversity Flashcards
How is diversity maintained
Mutation, sex, ploidy, balancing selection (heterozygote advantage and frequency dependant selection)
What do germ line mutations include
Point mutations such as insertion, substitution, deletion and inversion
What are synonymous/ silent mutations
Point mutations that don’t lead to change
What are Non-synonymous mutations
Mutations that lead to change, including missense, nonsense and frame shift
What do missense mutations do
changes a single amino acid in a protein
What do nonsense mutations do
Produce premature stop codons
What do frame shift mutations do
Shifts the number of base pairs
What is sickle cell amenia caused by
Single base change
What are large scale structural mutations
Large parts of the chromosome deleted or moved around
Example of inversion mutations
Wading birds and their different male morphs: Independence, satellite and faeder
What do mutation rates depend on
The type of mutation, the genome and the species
Do male or females have a higher mutation rate
Males due to more germ lines and cell divisions
What’s independent assortment
Sexual reproduction mixes the DNA from two haploid gametes to produce diploid offspring
Whats random fertilisation
Any sperm can fertilise any egg
What is crossing over
Flailing chromosomes exchnage genetic material between the chromosome pairs
What is ploidy
Diploid means twi copies of everything in the form of recessive alleles
What are the two types of balancing selection
Heterozygote advantage and frequency dependent selection
What does heterozygote advantage involve and example
Heterozygote is fittest over dominace for example, sickle cell anaemia in Africa
What does frequency dependant selection involve
The rarer alleles have the highest fitness:
Positive: fitness of genotype goes up in freuquency
Negative: fitness of a genotype goes down as frequency goes up
