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MIDTERM 2 Flashcards

1
Q

genetic locus

A

location of a gene or sequence within a chromosome

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2
Q

alleles

A

forms of a specific gene within a locus

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3
Q

What does the hardy-weinbergn principle states?

A

alleles frequences remain the same from gen to gen

phenotypic frequencies remain the same gen to gen

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4
Q

What circumstances are not considered in the hardy weinbergn princle?

A

large populations

different genotypes that differ in fitness

mutations

random mating

migration is not involved

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5
Q

what are the reasons why the genotypic frequencies do not conform to the weinberg principle?

A

nonrandom mating

or. evolution

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6
Q

what are mechanisms that populations evolve?

A

This cause the change of allelic frequencies.

gene drift

natural selection

migration (gene flow)

mutation

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7
Q

what is pleiotropy

A

a mutation in a gene can cause affect of many phenotypic traits

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8
Q

what is additive?

A

its an allele that yields twice the phenotypic effect when two copies are present

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9
Q

what is a polygenic trait?

A

a trait that influences other loci (influences other parts of a gene)

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10
Q

what is an example of the effects of a polygenic trait

A

interactions between alleles (epistatsis)

environment interactions (phenotypic plasticity)

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11
Q

Quantitative genetics

A

continuous phenotypic traits ex complex traits

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12
Q

how do you know how much a population changes

A

depends on selection differential and heritability

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13
Q

what is a quantitative trait locus?

A

it analysis links traits with genes

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14
Q

Phenotypic Plasticity

A

a single genotype that produces more than one phenotype depending on the environment

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15
Q

Reaction Norm

A

can predict the response in environment using maps.

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16
Q

what is an example of genetic synapomorphy?

A

the change of nucleotide base.
ex, G to T

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17
Q

what is positive selection?

A

allele that is involved in selective pressure evolve quickly therefore shorter distance to coalescence

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18
Q

Introgression

A

is where two species that are closely related to each other and still reproductivly compatabilite can interbred and produce a hybrid

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18
Q

what are synonymous mutations?

A

they are silent mutations that do not alter the amino acid seq of protein.
they are within the coding regions (exons)

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19
Q

why do genes differ in rate of evolution?

A

mutations on exons form slowly evolving genes useful for distantly related species.

mutations on introns form rapid evolving genes useful for closely related lineages

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19
Q

promiscuous

A

proteins capable of carrying out more than one function

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20
Q

what are non-synonymous mutations?

A

alter the amino acid seq of protein. Can affect splicng and regulation of gene expression

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21
Q

what is broad sense heritability?

A

Phenotypic differences are explained by genetic differences among individuals

22
Q

What is narrow sense heritability?

A

phenotypic variences are explained by ADDITIVE genetic variation (cause offspring to look like parents)

23
How do you estimate heritability?
The slope indicate narrow sense heritability (additive trait)
24
what does broad sense heritability include?
additive effects dominance effects Epistatic effects Maternal/Paternal environment effects
25
What makes a stabilizing selection?
when the oppsite sites oppose each other
26
how much the population changes?
by selection differential and heritability
27
What happens to the selection differential if the strength of selection is strong?
the selection differential (S) will be large and only the biggest individuals reproduce
28
what happens if the selection differential strength is weak?
The selection differential (S) is small and only big and medium individuals reproduce
29
how much will a trait evolve using the narrow sense and selection differential (S)?
R= h2xS
30
what are the forms that selection on quantitative traits occur
directional stabilizing disruptive
31
Can selection occur without evolution?
yes it can occur without evolution. Selection can occur by the strength of selection and heritability
32
how is the distance of coalescence from a time where strong positive selection occur?
The distance back to coalescence will be short because the selection is increased to fixation
33
what is homoplasy in phylogenetic trees?
there is a same mutation that occurs at the same base in seperate lineages
34
how does gene differ in rate of evolution?
slowly evolving genes are distantly related. (occur on exons, more convervative regions Rapidly evolving genes are closely related (occurs on non-coding regions, less conservative
35
what are the important points of Darwins study?
- single colonization event and then diverification occurs forming monophyletic groups
36
what is a molecular clock?
able to date fossils or events that can tell how long two lineages diverged
37
what is the molecular clock used for?
used to estimate the origin of disease and major clades
38
what happens to alleles when subjected to strong selection?
they spread quickly through populations
39
what is selective sweep?
adaptive allele spreads through population quickly lead to reduced genetic diversity
40
what is genetic hitchhiking?
strong selected alleles are found in a population surrounded by the same set of alleles at neighboring locations
41
what selection will leave genetic signatures that can be detected?
positive and purifying selection
42
what is the difference between the bacterial genome and eukaryotic genome?
Bacterial: - size dependent on many genes - Duplication, lateral gene transfer and increase size - bacteria adapted to host have smaller genome and lose functional genes Eukaryotic: - have more noncoding DNA than number of genes - mobile elements contribute to a large portion of the genome size
43
what are complex adaptations?
they are co-expressed traits that experience selection for a common function
44
what are casades?
They are regulatory networks that includes multiple genes that are dependent on each other
45
whats happens when a chromosome is duplicated?
can make function of a gene work differently
46
what happens to citrate metabolism?
a gene duplication insertion occurs causing the rnk promoter to express citT when oxygen present leading to the functioning of the transporter
47
what is the history of venom?
Initial Duplication: Beta-defensins are produced in skin to fight bacterial Second duplication: Beta-defensins are expressed in snake pancreas and other organs due to mutation in regulatory element Third duplication: evolve into crotamine venom and expressed only in venom glands in snakes
48
what is the evolution of eyes
First duplication event: a G-protein receptor was duplicated and evolved one copy with a hormone called melatonin and the other opsin Second duplication event: Opsins evolve to capture photons in animals. After duplications, opsins evolve to t-opsins in cnidarians, protosomes, and deuterostomes Third duplication event: produce two other types of opsins: c-opsins and RGR/Go opsins
49
how did crystallins evolve?
through gene recuitment. a mutation causes a whole different function
50
what is constraining evolution?
laws of physics pleiotropy
51
what is antagonistic pleiotropy?
negative side affect of genes ex. giraffe with one cervical vertebrae can cause depressed metabolism and increase cancer rates
52
what is parallel evolution?
Independent evolution of similar traits from similar ancestral
53

Evolution (3 decks)

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