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What will happen to DNA sequence variation in the regions of the genome immediately adjacent to an allele undergoing a selective sweep, or strong positive selection? a. Decreased variation and high levels of linkage disequilibrium at nearby sites

b. Increased variation and high levels of linkage disequilibrium at nearby sites

c. Increased variation and the absence of linkage disequilibrium at nearby site

d. Decreased variation and the absence of linkage disequilibrium at nearby sites

e. No change in local genetic variation

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Reid Wolff
Reid WolffLv2
29 Sep 2019

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Related questions

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

1. Humans have the scientific name Homo sapiens. We are members of the family Pongidae, in the order Primates, in the class Mammalia, in the phylum Chordata. Based only on this information, which of the following is not a correct statement?

a. The speciation event (lineage-splitting) that generated the genus Homo occurred earlier than the speciation event that generated the species H. sapiens.

b. The most inclusive of these taxonomic groups is Chordata.

c. The genus Homo might have as many species as are in the entire family Pongidae.

d. There can be no other species in the genus Homo.

e. All mammals must be Chordates.

2. Endotherms differ from ectotherms in that:

a. Environmental temperature has little effect on the energy budget of endotherms but a strong effect on the energy budget of ectotherms.

b. An endotherm's metabolic rate is not affected by temperature whereas the metabolism of an ectotherm has a Q10 of 2-3.

c. Endotherms are vertebrates and ectotherms are invertebrates.

d. On average, endotherms are much better sprinters (i.e., can run faster for short distances) than ectotherms.

e. Endotherms are much better able to support endurance exercise than ectotherms.

3. You measure oxygen consumption of a lizard at three temperatures, as follows: 18 °C: 0.090 ml O2/min 23 °C: 0.135 ml O2/min 28 °C: 0.200 ml O2/min From these data you calculate the Q10 to be:

a. 1.8

b. 2.0

c. 2.2

d. 2.5

e. none of these are correct.

4. What is the best description of how evolution by selection (natural or artificial) works?

a. mutation generates variation randomly, sex makes new combinations of genes randomly, and selection picks the best ones for reproduction.

b. selection leads to non-random mutation to make useful new alleles, which are then combined by sex.

c. exposure to environmental factors leads to non-random mutations that improve fitness.

d. through selection, mutations occur in those genes that will improve fitness.

e. mutation generates random new alleles, and sex combines them in ways that select the best for future generations.

5. Which of the following is a correct match between a major lineage and its characteristics?

a. Archaea: extremophiles, ribosomes, RNA as genetic material, no nuclear membrane

b. Eukarya: mitochondria, DNA as genetic material, photosynthetic or chemohetrotrophic

c. Bacteria: mitochondria, DNA as genetic material, no nuclear membrane

d. Eumetazoa: extremophiles, ribosomes, DNA as genetic material, nuclear membrane, chemoheterotrophic

e. Protostomes: triploblastic, eucoelomate, blastopore becomes anus, indeterminate cleavage

6. Which of the following statements about animal life history events is correct?

a. Being multicellular requires a larval stage in the life cycle.

b. Mutation is sufficient to produce considerable genetic variation between different tissues in an individual.

c. Senescence is defined by slow, constant decline in survival as individuals get older.

d. Different cell types are formed when different but specific portions of the zygote’s DNA are lost from the different germ layers during development.

e. In an individual, the only cells that differ genetically from other cells are gametes.

7. Which of the following statements about terrestrial vertebrates is correct?

a. Jaws evolved from paired appendages, which in turn evolved because they improved swimming ability.

b. Legs evolved from fins after early fishlike vertebrates invaded the land.

c. Jaws and inner ear bones evolved from gill arches, and leglike appendages evolved under selection for aquatic locomotion.

d. Viviparity (giving birth to well-developed young instead of laying eggs) was vital to the ability to reproduce on land without returning to the water.

e. Lungs for breathing air evolved after early fishlike vertebrates invaded the land (the first land vertebrates had to depend on gills for breathing air)

8. The essential features of a hydrostatic skeleton include:

a. antagonistic muscles.

b. a non-deformable fluid-filled space

c. flexible joints.

d. compressible material capable of changing volume

e. all of the above (a) – (d) are correct.

9. You are a Peace Corps volunteer physician in a developing country. You notice that some of the villages you visit have a high incidence of a parasitic disease, but other nearby villages are unaffected. Investigating you find the villages with disease are in wet areas with lots of snails and frogs, while the disease-free villages are in drier places but have lots of insects and mice. From this information, what might you reasonably conclude about the type of parasite responsible for the disease?

a. It’s a trematode (these need mollusks as intermediate hosts).

b. It’s a nematode (these are vectored mainly by frogs).

c. It’s an apicomplexan parasite (these require wet areas and enter the skin through standing water).

d. It’s a trypanosome (these are transmitted by mammal bites).

e. The information doesn’t provide useful clues about the type of parasite.

10. Which of the following pairs of primary diagnostic characters is correctly matched with taxonomic groups?

a. circulatory system vs. water vascular system: Nematoda vs. Echinodermata

b. schizocoely vs. enterocoely: Radiata vs. Bilateria

c. pharyngeal slits vs. polyp and medusa: Chordata vs. Cnidaria

d. gastrovascular cavity vs. complete gut: Cnidaria vs. Cestoda

e. hemocoel vs. contractile vacuole: apicomplexans vs. rhizopoda

Please provide explanation too.

1). Thyroid hormone (TH) has been identified as one of the factors promoting phenotype development in the Mexican axolotl salamander. Which of the following statements regarding the impact of TH is FALSE?

A). Axolotls maturing in water with high concentration of TH (thyroxine; T4) metamorphose into a terrestrial form.

B). A genome-wide scan of both the axolotl and its sister species found a large reduction in the number of mRNA transcripts that regulate the production of TH.

C). Adding TH (thyroxine; T4) to the water in which axolotl individuals are reared causes them to remain in a larval stage.

D). Most salamander species produce a burst of TH when they move from water to land.

2).What would be an appropriate evolutionary explanation of the fact that the ordering of some homeotic genes (such as Hox genes) on vertebrate chromosomes parallels the ordering of homeotic genes on fruit fly chromosomes?

A). The similarity is a coincidence, not documented in other invertebrates and largely a result of random mutations.

B). Homeotic genes show that insects and vertebrates are closer relatives than the traditional classification system indicates.

C). Homeotic genes of different animal lineages might be ordered in a similar fashion, yet their sequences are completely different.

D). The similar ordering of homeotic genes in animals, both vertebrate and insect, is due to ancient homology.

3). Which of the following correctly defines "homeotic genes"?

A). Homeotic genes encode proteins that control the cellular environment in a differentiated cell tissue.

B). Homeotic genes are DNA sequences that turn off, but not on, the expression of other genes and are controlled by "master-switch" genes.

C). Homeotic genes are "master-switch" genes that control other genes in a set sequence and thereby affect cell size, shape, division, and the positioning of the cells within the organism.

D). Homeotic genes are DNA sequences that turn on, but not off, the expression of other genes and are controlled by "master-switch" genes.

4). Which of the following is NOT considered a type of heterochrony (change in the rate and timing of development)?

A). hypermorphosis

B). acceleration

C). neoteny

D). ontogeny

5). How does the dominance theory explain why the heterogametic sex is at a disadvantage in Haldane's rule?

A). Beneficial dominant alleles will never be fully expressed in hybrids as they only carry one copy of the sex chromosome that carries the allele.

B). If a dominant allele has a negative effect on the fitness of hybrids, it will always be expressed in the heterogametic hybrids that possess that allele because they only need one copy of the respective sex chromosome.

C). If a recessive allele linked to a sex chromosome has a negative effect on the fitness of hybrids, that allele will always be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

D). If a recessive allele linked to a sex chromosome has a positive effect on the fitness of hybrids, that allele will never be expressed in the heterogametic hybrids that possess that allele because they only have one copy of the sex chromosome that carries the allele.

6). In a hypothetical flowering plant species, one population evolves a different response to environmental stimuli and begins to bloom significantly later in the season than nearby populations. What type of reproductive isolating mechanism would this be?

A). hybrid sterility

B). postzygotic

C). prezygotic

D). gametic incompatibility

7). In a study of red spruce trees and black spruce trees, scientists found that the red spruce was living in a smaller geographic area and had much less genetic variation than the black spruce. They proposed that the red spruce might have arisen from a southern population of black spruce, which became geographically isolated from other black spruce populations at some point during the Pleistocene glaciations. What is this an example of?

A). allopatric speciation with the vicariance model

B). sympatric speciation

C). allopatric speciation with the peripheral isolate model

D). sympatric speciation with the ring species model

8). Which of the following defines Haldane's rule and its predictions?

A). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always male.

B). If among hybrid offspring one sex is absent, rare, or sterile, that sex is always female.

C). If among hybrid offspring one sex is absent, rare, or sterile, that sex is heterogametic (has two different sex chromosomes).

D). If among hybrid offspring one sex is absent, rare, or sterile, that sex is homogametic (has two of the same sex chromosomes).

8.) Which of the following statements best explains secondary reinforcement?

A). If the reproductive isolating mechanisms that developed during the geographic isolation are strong but the hybrids have higher fitness than the parent species, then the speciation process will cease.

B). If the reproductive isolating mechanisms that developed during the geographic isolation are somewhat weak but the hybrids between two populations have lower fitness, then the speciation process may continue.

C). If the reproductive isolating mechanisms that developed during the geographic isolation are sufficiently weak as to allow free interbreeding across reunited populations, then the speciation process will halt and a single species will remain.

D). When geographic isolation comes to an end, two populations always complete the divergence process and become separate species.

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