Evolutionary Bio Exam 2

hardy-weinberg principle

explains how allele and genotype frequencies remain constant throughout generations without evolutionary influences

#individuals * ploidy

equation for total alleles in population

f[bb] + (f[Bb]/2)

allele frequency for b

f[BB] + (f[Bb]/2)

allele frequency for B

p + q = 1

allele frequency equation

p² + 2pq + q² = 1

H-W equation

genotype frequencies

what does p², 2pq, and q² represent

large population, random mating, no mutation, no migration, and no selection

needed for H-W equilibrium

large

hardy-weinberg assumption: the population is

allele frequencies

the population must be large to prevent random changes in…

genetic drift

random sampling effect that alters allele frequency

small

genetic drift is most powerful in…populations

evolution

change in allele frequencies from one generation the the next

hardy-weinberg equilibrium

if allele frequencies do not change through time, the population is in

hardy weinberg equilibrium

if allele frequencies change through time, the population is in

drift

mechanism in which imperfect sampling causes some alleles to be underrepresented relative to others

random sampling error

genetic drift results from

higher

sampling error is…with smaller samples

small populations

drift reduces genetic variation in…

meiosis

primary cause of random allele sampling

diverge

as a result of genetic drift, separate populations…

bottleneck

sudden reduction in population size due to some event

northern elephant seals and cheetas

examples of bottlenecks

bottleneck

rare alleles are likely to be lost in small populations or during a

founder effect

small group breaks off and forms their own population

mormons

example of founder effect

germ-line

only BLANK mutations are heritable

somatic

mutations that affect cells in the body of an organism that occur after conception

germ-line mutations

affects gametes; heritable and relevant to evolution

seperate germ line

in single-celled organisms, there is no…

single-celled organisms and totipotency in plants

exceptions to only germ-line mutations relevant to evolution

totipotency

term for a single cell dividing and growing, then differentiating into a complete, fertile adult plant

mutation, independent assortment, recombination, hybridization, horizontal gene transfer

sources of genetic variation

mutation

cause of genetic variation involving generation of alleles

point, insertion, deletion, duplication, inversion, chromosome fusion, and genome duplication

types of mutation

point

mutation where one base pair is replaced

insertion

mutation where an extra base pair is added

deletion

mutation where a section of the genome is lost

gene duplication

mutation where segments of the genome are copied

inversion

mutation in which a section of the genome is flipped backwards

chromosome fusion

mutation in which two chromosomes join together

denovo

mutations in offspring that were not in the parents

trio and sib studies

sequences genomes of mother, father, and one or more biological offspring

multi-generation pedigrees

sequences genomes to determine which generation and which parent’s germline did the mutation originate in

paternal age

mutation rate is strongly dependent on…

74.5

estimate of de Novo SNVs per generation

16-17

mutation count roughly doubles every…years of father’s age at conception

insertions and deletions

indel is a term for

indels

BLANK can cause major consequences in protein genes unless in multiples of three and in frame

transposable elements

can insert copies of themselves or jump elsewhere in the genome

transposition

moves transposable elements from one place to another

Alu elements

short, repetitive DNA sequences that make up >10% of the human genome; they can insert themselves within genes

Alu

elements implicated in many human diseases

no

do all, or even most, genes exist as a single copy in the genome

dynamic entities

genomes are

duplication, loss

genes are constantly undergoing…and…

redundancy and divergence

two fates of duplicate genes

divergence

fate of duplicated gene in which it is free to accumulate mutations and evolve new functions

neofunctionalization

duplicate gene takes on an entirely new function

subfunctionalization

the duplicate takes on a specialized role similar and complementary to the ancestral function (og function splits)

loss

most common fate of duplicated genes

families

most genes are part of larger gene…as the result of gene duplications

terpenoids

directly related of aromatic features of wine

ploidy

number of copies of unique chromosomes in a cell

speciation

polyploidy can result in instantaneous sympatric

sterile triploid progeny

diploid x tetraploid results in…

genome duplications

gene duplications on a grand scale

15

what percentage of all speciation in flowering plants involve WGDs

ancient polyploids

all flowering plants are…

genome size

total DNA in haploid set of chromosomes; based on number of base pairs

exons

coding DNA

does not

most of the genome…encode genes

mobile genetic elements

can move or copy themselves elsewhere

mobile genetic elements and ploidy

variation in genome size and complexity is due to

complexity

based on how DNA is used; how DNA is regulated and combined

recombination

homologous chromosomes swamp segments during prophase 1 in meiosis

prophase I

when does recombination occur

Mendel’s second law

law explaining independent assortment of chromosomes during meiosis creates gametes with a mixture of maternal and paternal chromosomes

genetic linkage

the physical proximity of alleles at different loci

less

loci that are physically close are…likely to be separated by recombination

non-random

genetic linkage results in a…distribution of allele combinations

linkage equilibrium

alleles at one locus segregate randomly with respect to other alleles at the other (frequency is the same)

linkage disequilibrium

alleles at different loci are nonrandomly associated; segregating together more often than expected by chance

horizontal gene transfer

transfer of genetic material between different species

bacteria

HGT is common in

fitness

reproductive success of an individual with a particular phenotype

survival to reproductive age, mating success, and fecundity

components of fitness

fecundity

number of offspring produced

relative fitness

fitness of a genotype standardized by comparison to other genotypes

average excess fitness

difference in fitness between average fitness of individuals with a given allele vs, the average fitness of the population as a whole

Δp = p0 x (a/w)

equation that describes the change in allele frequency due to selection

Δp

change in allele frequency

p0

starting frequency of allele

a

average excess fitness of allele

w

average fitness of the entire population

present

p0 is positive if the allele is

exists

w is positive if the population

decreases

if Δp is negative the allele…in frequency

a

what determines whether the selection increases or decreases the frequency of the allele

starting frequency

effectiveness of selection is directly proportional to the…