Exam 26: Evolutionary Genetics

Protein electrophoresis was the first molecular technique to measure genetic variation. However, this technique normally underestimates the true amount of genetic variation. Why?

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Question 1

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Protein electrophoresis underestimates the true amount of genetic variation because it only measures variation in the proteins themselves, rather than directly measuring the genetic variation in the DNA. This means that it may miss certain types of genetic variation, such as silent mutations or variations in non-coding regions of the DNA. Additionally, protein electrophoresis may not be able to detect all the different forms of a protein that can be produced by genetic variation, leading to an underestimation of the true genetic diversity present in a population. As a result, more advanced molecular techniques, such as DNA sequencing, are now used to more accurately measure genetic variation.

According to the molecular clock data in Figure 26.14 (below), approximately what proportion of differences (per amino acid site) has accumulated between the common ancestor of all vertebrates (including fish) and the common ancestor of humans and kangaroos?

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Question 2

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For most protein-coding genes, the rate of substitution in _ is considerably higher than in _.

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Question 3

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In most cases, different species are distinguished on the basis of:

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Question 4

What two factors are thought to play a critical role in sympatric speciation? Explain how they lead to sympatric speciation.

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Question 5

Which of the following are homologous?

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Question 6

Based on the gene tree in Figure 26.11 (below), which of the following pairs of genes are MOST similar?

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Question 7

Before the advent of molecular techniques, researchers indirectly assessed genetic variation in populations through the study of _____ diversity.

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Question 8

_____ is the idea that, if postzygotic isolating mechanisms exist between two species, then natural selection will favor traits that lead to the evolution of prezygotic isolating mechanisms.

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Question 9

How has molecular data helped resolve the evolutionary relationships among distantly related taxa?

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Question 10

The neutral-mutation hypothesis does NOT suggest that:

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Question 11

(a) What is a molecular clock? (b) In what situation(s) would it be especially useful? (c) Explain how a molecular clock is calibrated. (d) What are some known problems with using molecular clocks?

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Question 12

Which reproductive isolating mechanism is exhibited by two different Drosophila species where one species breeds in the early morning and the other in the afternoon?

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Question 13

How much genetic differentiation is required for reproductive isolation to take place?

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Question 14

The microsatellite study of bighorn sheep described in Section 26.1 was a study of:

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Question 15

In Darwin's finches (Figure 26.6, below), the species Geospiza magnirostris is MOST closely related to which species?

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Question 16

In Darwin's finches (Figure 26.6, below), which genera have the LATEST common ancestor in common?

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Question 17

Discuss the role of the availability of whole-genome sequences in understanding the evolutionary process.

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Question 18

A phylogenetic tree for three species, A, B, and C, is shown below. A particular DNA region that is shared by all three species is cloned from each species and sequenced. There are about 100 nucleotide substitutions between A and C and between B and C. There are only 20 differences between A and B. The fossil record indicates that the ancestor to A and B diverged from the ancestor to C around 10 million years ago. What is the best estimate of the divergence between A and B based on this information, assuming a constant rate of mutation and the same rate of mutation on all branches?

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Question 19

_____ are sets of genes that are similar in sequence but encode different products.

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Question 20

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Exam 26: Evolutionary Genetics

Protein electrophoresis was the first molecular technique to measure genetic variation. However, this technique normally underestimates the true amount of genetic variation. Why?

According to the molecular clock data in Figure 26.14 (below), approximately what proportion of differences (per amino acid site) has accumulated between the common ancestor of all vertebrates (including fish) and the common ancestor of humans and kangaroos?

For most protein-coding genes, the rate of substitution in _____ is considerably higher than in _____.

In most cases, different species are distinguished on the basis of:

What two factors are thought to play a critical role in sympatric speciation? Explain how they lead to sympatric speciation.

Which of the following are homologous?

Based on the gene tree in Figure 26.11 (below), which of the following pairs of genes are MOST similar?

Before the advent of molecular techniques, researchers indirectly assessed genetic variation in populations through the study of _____ diversity.

_____ is the idea that, if postzygotic isolating mechanisms exist between two species, then natural selection will favor traits that lead to the evolution of prezygotic isolating mechanisms.

How has molecular data helped resolve the evolutionary relationships among distantly related taxa?

The neutral-mutation hypothesis does NOT suggest that:

(a) What is a molecular clock? (b) In what situation(s) would it be especially useful? (c) Explain how a molecular clock is calibrated. (d) What are some known problems with using molecular clocks?

Which reproductive isolating mechanism is exhibited by two different Drosophila species where one species breeds in the early morning and the other in the afternoon?

How much genetic differentiation is required for reproductive isolation to take place?

The microsatellite study of bighorn sheep described in Section 26.1 was a study of:

In Darwin's finches (Figure 26.6, below), the species Geospiza magnirostris is MOST closely related to which species?

In Darwin's finches (Figure 26.6, below), which genera have the LATEST common ancestor in common?

Discuss the role of the availability of whole-genome sequences in understanding the evolutionary process.

_____ are sets of genes that are similar in sequence but encode different products.

Introduction to Genetics

Chromosomes and Cellular Reproduction

Basic Principles of Heredity

Sex Determination and Sex-Linked Characteristics

Extensions and Modifications of Basic Principles

Pedigree Analysis, Applications, and Genetic Testing

Linkage, Recombination, and Eukaryotic Gene Mapping

Chromosome Variation

Bacterial and Viral Genetic Systems

DNA: the Chemical Nature of the Gene

Chromosome Structure and Organelle Dna

DNA Replication and Recombination

Transcription

Rna Molecules and Rna Processing

The Genetic Code and Translation

Control of Gene Expression in Prokaryotes

Control of Gene Expression in Eukaryotes

Gene Mutations and Dna Repair

Molecular Genetic Analysis and Biotechnology

Genomics and Proteomics

Epigenetics

Developmental Genetics and Immunogenetics

Cancer Genetics

Quantitative Genetics

Population Genetics

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For most protein-coding genes, the rate of substitution in _ is considerably higher than in _.