Basic Evolutionary Genetics Flashcards by Courtney @Brainscape

Why did people who had unprotected sex with those infected with HIV not get the virus?

“broken” CCR5 gene (loss-of-function allele at CCR5 locus = no doorknob)

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The CCR5 is a ______ protein found on ____

trans-membrane protein found on CD4+ Helper T-cells

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HIV virus has ____ form(s) and they are ____ and _____

2 formsM-formT-form

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M-form of HIV is found

early during infection

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T-form of HIV is found

later during infection (along with M-form)

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M-form requires ____ to enter a CD4+ H T-cell

CCR5

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The cells without a “door knob” were immune to ____ form but not ___ from of HIV

M form but not T form

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What is the downside to having no CCR5? (homozygous for deltaCCR5 gene)

More prone to other infections, T-cells not as strong (aka prone to west-nile virus)

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Evolution via natural selection

non-random differential reproduction of genotypes due to differences in their associated phenotypes

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Darwinian Fitness is

the measure of differential reproduction of genotypes

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Individual fitness is…

the number of genome copies an individual leaves in the next generation

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polygenic traits

characters that are controlled by many genes at once

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quantitative traits

polygenic traits

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Selection on polygenic traits can lead do

very rapid evolution

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Heritability

the proportion of phenotypic variation due to genetic variation (all among individuals)

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What contributes to variation

Nutrition (environment) and genes

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When the slop of a heritability graph is 1 there is ____ heritability which means…

perfect heritability which means all variation due to genetic variation

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In When the slop of a heritability graph is 0…

there is no heritability

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R value depends on which variable?

hertability (h^2)

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whats the max and minimal response of h^2

1 and 0

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Sexual selection is

struggle between individuals of one sex for possession of the other

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The tradeoff for fedcundity is

survival

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response differential is

change over time

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intrasexual hypothesis is what and indicates what trait?

competition with other malesaggression and intimidation

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intersexual hypothesis includes what? and describe their properties

good genes-better physical attributematerial benefits- good providersensory exploitation - female attractionsexy sons-male with great genes makes great sonsintersexual conflict

the sexy sons trait creates what in the future populations

dominance of the trait

describe the attributes of sexual conflict

-predation increases-STDs-seminal fluid can have negative effects -resistance exchange of traits

In a trait graph the cost of a better gene =

how much more exposure to danger

in trait graph dotted line is

benefits with mates

in trait graph equilibrium point is the balance betwwen

of sexual and survival selection

ability to provide resources (material benefits)

What leads to the lowering of Darwinian fitness?

Traits that reduce survival

Altruism

a trait that increases the fitness of others but reduces their own

Altruism ultimately leads to a D.fitness of

zero

What is kin selection?

reproductive success that is driven by augmenting the fitness of relatives

In order for kin selection to happen

an indv. needs to be small relative tot he degree of relatedness and benefit to the relative

What is Hamilton's Rule?

What is "C" in Hamilton's rule?

fitness coast of altruistic trait

R in Hammys rule?

relatedness

Values for R in relatedness

1/2 son-daughter1/2 brother sister1/4 grandchild1/8 1st cousin

In kin selection/altruistic conditions, the offspring ______ to the fitness of the parents

add

As long as Hammies Rule works then \_\_\_\_\_

kin selection is present

What is the positive feedback loop?

cycle of adaptation & counter-adaptation

Coevolution is when

two species evolve together/interchangeably

Two types of coevolution

interspecificintraspecific/intergenic

Interspecific coevolution is

two speices evolve in response to each other

intra/intergenic coevolution is

two GENES in the genome of the SAME species evolve in response to each other

The two forms for each type of Coevolution is

antagonisticmutualistic

Describe antagonistic interspecific coevolution and what is the "main name" for that

one species targets another and then the other evolves to adapt; "Red Queen"

mutualism can turn into parasitism if a species

"cheats"

the "cheater allele does not accumulate in the gene pool because

the affected species "penalizes" the cheater gene in one way or another

Describe antagonistic intra/intergenic situation

sperm and egg; lysin and egg matrix

T/F: Lysin is one of the most rapidly evolving genes

True

Describe mutualistic intergenic/intraspecific situation

insulin and insulin-receptor gene

The common sexy ratios found in nature and rareity

100% female (asexual; very rare)mostly female (rare)50/50 male to female (normal)

Mostly female indicates what type of breeding

inbreeding

50/50 male-female indicates what type of breeding

outbreeding

T/F: sex ratio is completely controlled by Mendellan segregation of sex chromosomes

FALSE

Percentage difference of male and females can also be due to

organisms interaction and response to the envrionment

To understand sex ratio evolution we need to look at what level of offspring?

grand-offspring

What is the fitness for grandoffspring?

grand-offspring/4

When there is a bias in the sexy ratio, the greater fitness is achieved by the

rarer sex

For random mating, all sex ratios eventually lead to

50/50

What is the effect of limited space to reproduce on offspring grow together

inbreedinghigher female ratio due to more grand-offspring

The more male biased a population the ___ the grand-offspring

lower

In the sex ratio theory, the maximum of grand offspring is reached:in a 50/50 ratio when \_\_\_in a inbreeding ratio when \_\_\_

the rare sex is producedif more females are produced

Species are

groups of individuals that exchange hereditary material under natural conditions

Reproductive Isolation Mechanisms (RIMS) are

ways that allow separate species to develop

Post - zygotic RIM

offspring are produced but are sterile or die before reproductive maturity

Pre-zygotic RIM

When species don't even mate or get to produce a zygote (lock and key analogy)-behavior-anatomy-physiology

Behavioral isolation also involves what preference?

habitat

2 types of geographical speciation

AllopatricSympatric

Describe allopatric

species are physically isolated from one another and they develop differently into a whole new species

Describe sympatric

all species are together in one place, with no physical barrier to genetic exchange

T/F: There is a method of direct selection for reproductive isolation

FALSE; species don't encounter one another

Allopatric speciation leads to what type of isolation? Why?

pre-zygotic, because the species develop different BPM attributes that prevent mating

What is positive assortative meeting

when individuals with similar phenotypes/preferences mate and "assort" the species more

reproductive isolation (pre-zygotic isolation-alloppatric speciation) leads to what type of mating?

positive assortative

Why does (+) assortative mating (pre-zygotic isolation) lead to speciation?

it leads to pleiotropy

What is pleiotropy

the same gene has multiple phenotypic effects

Pleiotropy can lead to what type(s) of isolation?

both pre-/post-zygotic isolation

Speciation in allopatry can ALSO occur in sympatry due to

pleiotropy (mating preference)

What is disruptive selection?

natural selection that favors 2 phenotypes at opposite extremes

Philopatry

offspring returning to where their parents mated

T/F: Philopatry can also lead to reproductive (pre-zygotic-positive assortment) isolation

True!

To get a 50% chance of philotropy what must occur?

Random mating

What leads to 100% of offspring returning to parents mating ground?

CompletephilopatryPerfect postitive assortmentcomplete pre-zygotic isolation

no philpatry = ( in terms of philopatry)

no pre-zygotic isolation

Philopatry is an example of what speciation

sympatric

When determining phylogeny through changes in bases, start off by

finding how many changes in bases there are relative to the outgroup and then order from least to greatest