Exam 3

Question 1

When was the first process available for mapping genes relative positions onto chromosomes?

Answer 1

cross breeding experiments in strains of fruit flies that estimated the rate of recombination between genes

Question 2

The overall phenotype of an organisms is determined by ____ and the environment

Answer 2

its genotype

Question 3

Which of the adaptive landscapes would have the strongest force of balancing selection for the two depicted traits?

Answer 3

it would tend to maintain high overall diversity

Question 4

Why is looking for regions of the genome that are very similar across organisms (conserved) such an important part of understanding genome evolution?

Answer 4

these regions indicate areas of homology and so are the foundation for all comparative studies

Question 5

A euglena is a single celled eukaryote that is much less complex than an otter. However, based on this information we still cannot determine which of these organisms has the largest genome. What is the name of the phenomenon and what is its main explanation?

Answer 5

C-value paradox, variable amounts of non-protein coding DNA in eukaryote genomes

Question 6

The human genome is

Answer 6

composed mostly of nuclear DNA but also includes a small amount of mitochondrial DNA
approximately 98.5% non-coding DNA

Question 7

Which of the following is not one of the steps when performing shotgun sequencing of a genome?

Answer 7

identify conserved haplotype blocks to serve as assembly anchors

Question 8

What is the best description for a synteny comparison of the genomes of maize (corn) and rice?

Answer 8

these two species have a high percentage of genes in common, however they have very divergent arrangement of these genes

Question 9

Eukaryotes

Answer 9

large portions of their genomes are composed of introns
for most species a majority of their genome is non protein coding

Question 10

Prokaryotes

Answer 10

nearly all of their genomes are circular in arrangement

Question 11

Both eukaryotes and prokaryotes

Answer 11

genome rearrangement is frequent and even closely related species/strains exhibit a difference in synteny

Question 12

Neither eukaryotes or prokaryotes

Answer 12

their genomes are composed of either double stranded DNA or single stranded RNA

Question 13

I examine all the coding sequences in Pandinus imperator (Emperor scorpion) and identify each codon that translates into proline with the following results:10% CCA, 15% CCC, 12% CCT, 63% CCG. Which of the following statements is best supported by this result?

Answer 13

there is a strong selective force for increased translational efficiency in this species

Question 14

The number of proteins coding sequences (G-value) is not predictive of morphological complexity among eukaryotic organisms. Which of the following is not an explanation for this?

Answer 14

transposons can greatly increase morphological complexity of the organisms in which they are found

Question 15

The genomes of _________ are most similar to those of the first living organism on earth

Answer 15

bacteria

Question 16

What is different about telomeres and centromeres compared to other parts of chromosomes?

Answer 16

They dont have much coding DNA however they are critical for other reasons therefore they are under different selective forces than most of the chromosome

Question 17

Why is the census population N size is always larger than the effective population size Ne for natural populations?

Answer 17

predation
infertility due to epistatic conflict
random accidents that fill offspring before maturity
disease

Question 18

Which of the following would be the most likely result if a population experienced a bottleneck event?

Answer 18

reduction in the genetic diversity across all parts of the genome

Question 19

Which of the following is not a reason why we would expect most evolution to be effectively neutral?

Answer 19

the mitochondrial genome is smaller and separate from the nuclear genome

Question 20

Which of the following examples best illustrates the statement “ontogeny recapitulates phylogeny”?

Answer 20

early human embryos have a relatively large post anal tail and folds of tissues that look very similar to developing amphibian gills

Question 21

which of the following is an example of an active trend?

Answer 21

increase in size among horse species as they evolved during the Cenozoic era

Question 22

Ka/Ks > 1

Answer 22

a scientist is looking for genes that are significant in creating the difference between two recently diverged species

Question 23

Ka/Ks = 1

Answer 23

a scientist is comparing the non-coding DNA of two species that he suspects might be interbreeding

Question 24

Ka/Ks < 1

Answer 24

comparing a homologous copy of insulin across five species of mammal. insulin is a critical gene for survival and is performing a nearly identical function in each species

Question 25

Coalescent theory uses which two values when evaluating diversity of population and attempting to estimate recent history of a population

Answer 25

effective population size Ne and mutation rate

Question 26

Which of the following would indicate that a group of cells is pluripotent?

Answer 26

at an early stage a research carefully divides a zygote in half. each of these halves develops into a healthy embryo a group of cells given a set of treatments differentiates into monocytes, the same group of cells when treated differently differentiates into neuroblasts

Question 27

Which of the following is a good example of a mutation that could be classified as heterochrony?

Answer 27

the mexican salamander (axolotl) which maintains many juvenile features throughout its lifespan

Question 28

Hox genes are found in ___

Answer 28

animals

Question 29

What is the general role of Hox genes?

Answer 29

transcription factors

Question 30

In species that have them, the Hox genes are usually found right next to each other in the genome. What is this arrangement called?

Answer 30

colinearity

Question 31

What is the developmental module?

Answer 31

a network of interconnected developmental genes that are used to build multiple, similar parts of organisms

Question 32

Which of the following outcomes apply to paralogous copies of a single ancestral gene?

Answer 32

the most likely long-term outcome is that one of the copies will mutate and become a pseudogene the initial outcome is redundancy of gene function its possible that one of these copies will take on a new function and increase the diversity of the species that carries these genes

Question 33

A ring species is a complex mix of allopatric and ___ speciation impacting multiple populations spread around a central barrier.

Answer 33

parapatric

Question 34

A population of cicadas diverges because of temporal differences in when they emerge and mate, however they share the same range. Which of the following modes of speciation best describes this speciation event?

Answer 34

sympatric

Question 35

A bacterium picks up a piece of DNA from its environment and incorporates it into its genome. This is a form of horizontal gene transfer (HGT) and is called ______________.

Answer 35

transformation

Question 36

Premating

Answer 36

mice look for chemical cues in a mate and will not mate with individuals that do not meet instinctive criteria

Question 37

Prezygotic

Answer 37

Several species of coral all release their eggs and sperm into the water column at the same time, however eggs and sperm from different species will not undergo fertilization.

Question 38

Postzygotic

Answer 38

mules are the offspring of a donkey and a horse and are completely sterile Occasionally a red shafted flicker will mate with a yellow shafted flicker, their offspring are healthy but have a very hard time finding a mate among either parental population

Question 39

Which characteristic of a population would be the least likely to help it survive a cataclysmic event?

Answer 39

complex sensory systems

Question 40

Healthy ecosystems are free of extinction

Answer 40

false

Question 41

Evolution via phyletic gradualism _____

Answer 41

is the pattern Darwin described and has no strong correlation between anagenesis and cladogenesis

Question 42

Of all mass extictions recorded in the fossil record, which had the largest impact in terms of the percentage of species lost

Answer 42

permian extinction

Question 43

The 6th mass extiction is cause by _____

Answer 43

anthropogenic changes

Question 44

Character displacement

Answer 44

its when open ecological niches enable the specialization of a subset of the population. This relieves some of the pressure of competition and is an important process leading to speciation