Chapter 6 Flashcards
Thought to be blending – equal parts mother and father
Inheritance
each individual has two gene copies at each locus
LoS
The F1 purple flowers received and retained parental variation
Law of Segregation
Each individual with 2 factors (genes)
Law of Segregation
Also established dominant nd recessive traits
Law of Segregation
Allele passed down at one locus was independent of that at another
Now – only in unlinked loci
Law of Independent Assortment
If flower color and wrinkled vs. smooth seeds are unlinked can select for purple without regard for seed coat
NS
would reduce variation
Blending
would preserve variation
Particulate
If a new, beneficial mutation arises, it would be swamped in the next generation
- this disappears with
particulate inheritance
different versions of a gene at a locus
alleles
location on a chromosome
locus
combination of alleles at a given locus
genotype
same 2 copies
homozygotes
different copies
heterozygotes
heterozygote is intermediate
codominant
Control rate of RNA transcription
Regulatory Elements
Most change is here
Regulatory Elements
Enhancers – increase rates
Silencers – decrease rate
Regulatory Elements
Change in base in DNA
Provides raw material for NS
Mutation and Variation
no change in amino acid
synonymous or silent mutation
purine to purine, pyrimidine to pyrimidine
Transition
purine to pyrimidine or vise versa
Transversion
causes a change in amino acids
Missense Mutation
Stop codon in middle of gene
Nonsense Mutation
Genetic dwarfism in cattle, cystic fibrosis (CFTR, rarer than missense or deletions)
Nonsense Mutation
Add or take away base pairs
Insertions and Deletions
multiple of three
In-frame
lose or gain AA, change protein
In-frame
changes reading frame
Frameshift
new series of AA
Frameshift
copy 1 or more genes
Gene duplications
whole genome (change in ploidy)
Chromosomal duplications
sections lost
Chromosomal deletions
(move to another chromosome)
Translocation
(flip sections)
Inversions
are random and so are there effects
mutations
a change in environment does not lead to favorable ones
- they have to have been there
mutations
Vary by tissue, species, higher taxon, nucleotide to nucleotide, and along chromosome
mutation rates
in mutation rates. microbes ________ with genome size
decreases
in mutation eukaryotes _____
increases
mother may have effect on offspring based on her condition
Maternal effects -Sources of Variation
more rare but possible
Paternal effecrs -Sources of Variation
present at birth
Due to genes, maternal effects and environment
Must be able to tease out genetic and other effects
congenital difference- Sources of Variation
