Biology 3593B Lecture Notes - Lecture 7: Chromosomal Rearrangement, Allele Frequency, Genetic Drift

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11 May 2020

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The key question: what processes may lead to change in allele frequencies: we know evolution is a change in allele frequency within a population; there are four processes can change allele frequency: Natural selection: all of these can cause evolution, but only natural selection results in adaptation. N. b. we want to look at non-synonymous mutation for the case of evolutionary biology. Case study white throated sparrow: there are two breads of white-throated sparrow with a different morph each e. g. white. Sparrow and tanned sparrow: they"re a case of chromosomal rearrangement as they either have the presence of. Tan males invest heavily in parental care and mate guarding. Is when one part of the chromosome became attached to another chromosome; example is. Robertstonian translocation" which is fusion between two acrocentric chromosomes (where the centromere is located quite near one end of the chromosome). Definition: random changes in gene frequencies in a population.

Related Questions

Which of the following provides evidence for evolution?

All of these answers are correct

Comparing DNA sequences between species

Looking at the geographic distribution of similar species

Analyzing transitional fossils

Which one of the following statements is true?

Natural selection works on non-heritable traits.

Mutations only give rise to harmful traits.

Natural selection works on variation already present in a population.

Individuals evolve through natural selection.

Which one of the following can create new alleles?

Which of the following is true concerning evolution?

An individual can evolve

Genetic drift is a non-random part of natural selection

An organism's fitness is determined by how long it survives

Natural selection occurs through a change in allele frequency

All living things need carbon. How does carbon enter the living portion of an ecosystem?

Atmospheric carbon dioxide taken in by photosynthesis.

Atmospheric carbon dioxide taken in by soil bacteria.

Elemental carbon taken in by plant roots.

Elemental carbon taken in by cellular respiration.

Elemental carbon taken in by cellular transpiration.

The burning of fossil fuels:

Releases excess carbon dioxide into the atmosphere.

Removes pollutants from the atmosphere.

Was developed by scientists to combat global climate change.

Has no effect on the carbon cycle.

Is good for the environment

__________ conducts water and dissolved minerals from the __________ to the ___________.

Phloem; roots; shoots

Xylem; roots; shoots

Phloem; shoots; roots

Xylem; shoots; roots

What is a disadvantage of growing traditional crops such as corn, soy or sugar cane for making biofuel?

they require lots of land and fresh water

they take carbon dioxide out of the atmosphere

they release oxygen into the atmosphere

they release water through their stomata

______ is the source of the oxygen gas released by a photosystem.

Through what structure(s) do plants obtain most of their water?

Need help with evolution questions:

1.) A haplotype is best defined as the ________________.

	haploid genotypes of all the gametes produced by a diploid individual

ABO blood type conferred by an individual gamete

genotype of either the paternal or maternal chromosomal complement

multilocus genotype of a chromosome or gamete

2.) Which of the following statements regarding linkage disequilibrium is true?

Exists when D is less than zero, but not when it is greater than zero.

Is reduced by sexual reproduction.

Is increased by crossing-over during meiosis.

Is increased by any random sampling error that happens to create or destroy certain chromosome genotypes but not others.

Is reduced by selection that favors certain combinations of genotypes.

3.) Selection on multilocus genotypes in random-mating populations leads to linkage disequilibrium when _______________.

it reduces mutation rates

it eliminates all haplotypes from the population

it prevents crossing-over during meiosis

some allele combinations confer greater fitness than do others

4.) When two loci are in linkage equilibrium, the allele carried on a chromosome at one locus is independent of the allele carried on the chromosome at another locus. When this is the case, _________________.

allele frequencies will not change over time

the two loci (or, more specifically, their protein products) do not interact

the frequency of each haplotype can be calculated by multiplying the frequency of its two alleles

all possible haplotypes occur at equal frequency

5.) Which of the following accurately characterize(s) Muller's ratchet model for the selective advantage of sexual reproduction?

Drift establishes linkage disequilibrium because multilocus genotypes with few mutations are eliminated by chance events.

In populations without sexual reproduction, deleterious mutations accumulate, eventually imposing such a burden that the population goes extinct.

Sex is favored selectively because it recreates the zero-mutation genotypes lost due to drift.

All of the above correctly characterize Muller's ratchet model for the evolution of sexual reproduction.

6.) The genetic signature of recent positive selection on a locus is _______________.

high frequency and low linkage disequilibrium

low frequency and low linkage disequilibrium

low frequency and high linkage disequilibrium

high frequency and high linkage disequilibrium

7.) Sexual reproduction is advantageous both in changing environments and in constant environments, compared to asexual reproduction.

True

False

8.) Sexual reproduction causes genetic recombination via crossing-over, which combines genotypes from different parents.

True

False

9.) One reason sex may be maintained in natural populations is proposed by the "Red Queen Hypothesis", which states that.....

genotypes created by sex are created by natural selection over and over

recombination creating novel genotypes that can resist infection by parasites

mutation load is reduced by novel adaptive mutations

the ability of sex to fix multiple

Random, chance events that change allele frequencies are knownas:

A. Gene flow

B. Genetic drift

C. Natural selection

D. Balancing selection

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Question 21 pts

What type of selection acts to maintain the two extremephenotypic variants in a population?

A. Disruptive selection

B. Directional selection

C. Positive selection

D. Artificial selection

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Question 31 pts

Approximately, how much of our DNA is shared with our closestrelatives, chimpanzees?

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Question 41 pts

The large canines of male baboons are likely the result of________, while the fact that some male baboons are very colorfulis probably the result of _______.

A. Mutation; balancing selection

B. Gene flow; sexual dimorphism

C. Male competition; female choice

D. Mate choice; genetic drift

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Question 51 pts

Negative assortative mating results in an increased frequency ofhomozygous genotypes within a population.

True

False

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Question 61 pts

Genetic evidence suggests that humans and Neandertals neverinterbred.

True

False

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Question 71 pts

The specific variant of the FOXP2 gene associated with languageacquisition in humans is found in both humans and Neandertals.

True

False

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Question 81 pts

Industrial melanism describes the change in moth color from paleto dark after pollution from factories resulted in coating treetrunks with a layer of dark soot. Which statement is trueconcerning industrial melanism?

A. After pollution levels increased, all moths became darkercolored because soot got on their wings

B. The dark moths survived better after pollution levelsincreased because they were not poisoned by the pollutants

C. Individual moths changed their color in response to thepollution

D. Dark moths were present in the population before pollutionlevels increased

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Question 91 pts

Patterns of evolution can be seen above the species level

True

False

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Question 101 pts

Inbreeding is problematic because it increases the probabilitythat offspring inherit two copies of a recessive mutation thatcauses disease.