mutation and variation pt 2 Flashcards
a single base has been inserted into the sequence
point insertion
a single base deleted from the sequence
point deletions
insertions/deletions throw off the codon _______ ________ resulting in s sequence of amino acids that has no (or a different ) function
reading frame
we know the majority of mutations are
deleterious or neutral
Describe Denver study with roundworms
Used hermaphroditic roundworms and used one individual to establish mini lines. He maintained them in optimal conditions
Why did Denver keep the worms and optimal conditions (temperature, humidity, minimal crowding, abundant food, etc. )
This decreased the role of natural selection, and maximize the probability of mutations being passed from parents offspring
after comparing his experimental worms to those of a normal population, Denver had 2 main findings
- fitness aspects declined with indiviviudals with mutations when compared to populations without mutations
- individuals with mutations general less likely to survived to reproduce- and reproduced less offspring if they did survive
mutationscan change the sequence of amino acids and can (3)
1 alter function of protein
2 destroy/delete function of protein
3 cause death
mutations can be a powerful force of evolutionary change when couple with
selection
why did the E. coli in lenski’s experiment increase in jumps?
the jumps corresponded to beneficial mutation that was selected for (able to reproduce faster and use more resources)
gene duplications can lead to
new genes
most gene duplication events occur because of
chromosomal alterations
what Is unequal crossover?
during alignment homologous chromosomes commonly undergo crossovers , this can result in one chromosomes having 2 copies of the same gene
term for genome duplication
polyploidy
diploid plants and animals that can self fertilize can produce _____ (4n) offspring
tetraploid
can polyploid and diploid organism mate?
no they are reproductively isolated(new species)
5 summary points from mutations and fitness
1 mutations occur in a variety of types
2 mutations frequent on per genome/per generation basis
3 mutations introduce new alleles, most are deleterious
4 most deleterious mutations removed via natural selection
5 mutations rates can vary among sexes, individuals, populations, species, and lineages
mutations continually introduce new alleles but most are
deleterious
most deleterious mutations are removed via
natural selection
