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Campbell Biology

Lisa A. Urry

Chapter 21

Genomes and Their Evolution - all with Video Answers

Educators

Chapter Questions

01:07

Problem 1

Bioinformatics includes
(A) using DNA technology to clone genes.
(B) using computer programs to align DNA sequences.
(C) using a person's genomic sequence to inform decisions about medical treatment.
(D) amplifying DNA segments from a species' genome.

Courtney Burson
Courtney Burson
Numerade Educator
02:02

Problem 2

Homeotic genes
(A) encode transcription factors that control the expression of genes responsible for specific anatomical structures.
(B) are found only in Drosophila and other arthropods.
(C) are the only genes that contain the homeobox domain.
(D) encode proteins that form anatomical structures in the fly.

MR
Michael Richmond
Numerade Educator
05:38

Problem 3

Two eukaryotic proteins have one domain in common but are otherwise very different. Which of the following processes is most likely to have contributed to this similarity?
(A) gene duplication
(C) exon shuffling
(B) alternative splicing
(D) random point mutations

MR
Michael Richmond
Numerade Educator
08:55

Problem 4

Below are the amino acid sequences (using single letters; see Figure 5.14 ) of three short segments of the FOXP2 protein from five species. These segments contain all amino acid differences between the FOXP2 proteins of these species. Compare the amino acid sequences by answering parts (a)-(d).
Chimpanzee PKSSD ... TSSTT ... NARRD
Mouse PKSSE ... TSSTT ... NARRD
Gorilla PKSSD ... TSSTT ... NARRD
Human PKSSD ... TSSNT ... SARRD
Rhesus monkey PKSSD ... TSSTT ... NARRD
(a) Circle the names of any species that have identical amino acid sequences for the FOXP2 protein.
(b) In the sequence for the mouse, circle any amino acid that differs from the sequence for the chimpanzee, gorilla, and rhesus monkey. Then draw a box around any amino acid that differs from the human sequence.
(c) In the human sequence, underline any amino acid that differs from the sequence for the chimpanzee, gorilla, and rhesus monkey.
(d) Primates and rodents diverged about 65 million years ago, and chimpanzees and humans diverged about 6 million years ago (see Figure 21.17 ). How many amino acid differences are there between the sequence for the mouse and the sequence for the chimpanzee, gorilla, and rhesus monkey? How many amino acid differences are there between the human sequence and the sequence for the chimpanzee, gorilla, and rhesus monkey? Based solely on the numbers of amino acid differences occurring over these time periods, what might you hypothesize about the rate of evolution of the $F O X P 2$ gene? Based on the information in the chapter regarding the FOXP2 gene, is your hypothesis correct?

Courtney Burson
Courtney Burson
Numerade Educator
03:03

Problem 5

Genes important in the embryonic development of animals, such as homeoboxcontaining genes, have been relatively well conserved during evolution; that is, they are more similar among different species than are many other genes. Explain why this is.

Courtney Burson
Courtney Burson
Numerade Educator
01:51

Problem 6

The scientists mapping the SNPs in the human genome noticed that groups of SNPs tended to be inherited together, in blocks known as haplotypes, ranging in length from 5,000 to 200,000 base pairs. There are as few as four or five commonly occurring combinations of SNPs per haplotype. Integrating what you've learned throughout this chapter and this unit, propose an explanation for this observation.

Prashant Bana
Prashant Bana
Numerade Educator
03:36

Problem 7

The continuity of life is based on heritable information in the form of DNA. In a short essay (100-150 words), explain how mutations in proteincoding genes and regulatory DNA contribute to evolution.

Courtney Burson
Courtney Burson
Numerade Educator
03:22

Problem 8

Insects have three thoracic (trunk) segments. While researchers have found insect fossils with wings on all segments, modern insects have wings or related structures on only the second and third segment. In modern insects, Hox gene products act to inhibit wing formation on the first segment. The treehopper insect (above) is an exception. In addition to the pair of prominent wings on its second segment, its first segment has an ornate helmet resembling a set of thorns, which is a modified, fused pair of "wings." (This provides camouflage in tree branches, reducing the risk of predation.) Explain how changes in gene regulation could have led to the evolution of such a structure.

Courtney Burson
Courtney Burson
Numerade Educator