Page 11 - Genetics_From_Genes_to_Genomes_6th_FULL_Part1

x Preface

The understanding of molecular and computer-based integrates photos and line art in a manner that provides
techniques carries into our discussion of chromosome spe- the most engaging visual presentation of genetics
cifics in Chapters 12–15, and also informs our analysis of available. Our Feature Figure illustrations break down
gene regulation in Chapters 16 and 17. Chapter 18 describes complex processes into step-by-step illustrations that
the most recent technology that scientists can use to ma- lead to greater student understanding. All illustrations
nipulate genomes at will – for research and practical pur- are rendered with a consistent color theme—for
poses including gene therapy. Chapter 19 describes the use example, all presentations of phosphate groups are the
of genetic tools at the molecular level to uncover the com- same color, as are all presentations of mRNA.
plex interactions of eukaryotic development. In Chapter ∙ Accessibility Our intention is to bring cutting-edge
20, we explain how our understanding of genetics and the content to the student level. A number of more
development of molecular genetic technologies is enabling complex illustrations are revised and segmented to
us to comprehend cancer and in some cases to cure it. help the student follow the process. Legends have been
Chapters 21 and 22 cover population genetics, with a streamlined to highlight only the most important ideas,
view of how molecular tools have provided information and throughout the book, topics and examples have
on species relatedness and on genome changes at the been chosen to focus on the most critical information.
molecular level over time. In addition, we explain how ∙ Problem Solving Developing strong problem-solving
bioinformatics can be combined with population genetics skills is vital for every genetics student. The authors
to understand inheritance of complex traits and to trace have carefully created problem sets at the end of each
human ancestry. chapter that allow students to improve upon their
Throughout our book, we present the scientific reason- problem-solving ability.
ing of some of the ingenious researchers of the field—from ∙ Solved Problems These cover topical material with
Mendel, to Watson and Crick, to the collaborators on the complete answers provide insight into the step-by-step
Human Genome Project. We hope student readers will see process of problem solving.
that genetics is not simply a set of data and facts, but also a ∙ Review Problems More than 700 questions involving
human endeavor that relies on contributions from excep- a variety of levels of difficulty that develop excellent
tional individuals. problem-solving skills. The problems are organized by
Solved Problems
chapter section and in order of increasing difficulty 359
within each section for ease of use by instructors and
Student-Friendly Features students. The companion online Study Guide and
each of us has our own human genome that is closely re- differences between the genomes of many individuals so
Solutions Manual, completely revised for the 6th
lated to that of all other humans but is also distinct and
we can understand the genetic basis of phenotypic varia-
As digital components of the text become more and more edition by Michael Goldberg and Janice Fischer,
tion; for example, finding the nucleotide differences re-
unique. It is the differences between the genomes of indi-
crucial, we are very excited that Janice Fischer, a textbook provides detailed analysis of strategies to solve all of
viduals that cause each of us to possess our own distinct
sponsible for far-ranging and varied effects on human
author, is taking on a dual role as Digital Editor! Janice will the end-of-chapter problems.
and unique phenotype.
health. In Chapter 11, we describe how geneticists can now
The sequence and even the annotation of one human
ensure the important consistency between text and digital. look at the genomes of many individuals to track genetic
genome is only the beginning. The human RefSeq provides
We have taken great pains to help the student make the variation and to identify those differences in DNA se-
a reference mark toward identifying and analyzing the
quence that underlie important traits.
leap to a deeper understanding of genetics. Nu merous
features of this book were
developed with that goal in SOLVED PROBLEMS
mind.
∙ One Voice Genetics: I. The following figure shows a screen shot from the b. The arrows within the introns of the gene show that
UCSC Genome Browser, focusing on a region of the hu-
Genes to Genomes has a man genome encoding a gene called MFAP3L. (Note: the direction of transcription is from the telomere of
4q toward the centromere of chromosome 4.
friendly, engaging hg38 refers to version 38 of the human genome RefSeq.) c. The data indicate four alternatively spliced forms of
reading style that helps If you do not remember how the browser represents the the mRNA. In the following parts, we list these as A
genome, refer to the key at the bottom of Fig. 10.3.
students master the to D from top to bottom.
concepts throughout this d. The data suggest two promoters. One is roughly at po-
book. The writing style sition 170,037,000 and allows the transcription of a
primary RNA alternatively spliced to produce
provides the student mRNAs B and D. The other is roughly at position
with the focus and 170,013,000 and leads to the transcription of a pri-
continuity required to mary RNA alternatively spliced to generate mRNAs
A and C.
make the book Source: University of California Genome Project, https://genome.ucsc.edu e. The data indicate that the MFAP3 gene can encode
successful in the a. Describe in approximate terms the genomic loca- two different but closely related proteins. mRNAs A,
classroom. tion of MFAP3L. B, and C all encode the same protein; mRNA D a
∙ Visualizing b. Is the gene transcribed in the direction from the slightly larger protein that includes at its N terminus
additional amino acids not found in the other protein.
centromere-to-telomere or from the telomere-to-
Genetics The highly centromere? Otherwise these two proteins appear to be the same.
specialized art program c. How many alternative splice forms of MFAP3L The ORF that encodes the A B C protein form is
developed for this book mRNA are indicated by the data? about 880 bp long (a rough estimate); this corre-
sponds to about (880/3 = 293 amino acids). The D
d. How many different promoters for MFAP3L are protein is about 50 amino acids longer.
suggested by the data?
e. How many different proteins does the MFAP3L II. Two parents from Southeast Asia have a stillborn
gene appear to encode? Which alternatively spliced child with a lethal condition called hydrops fetalis.
forms of the mRNA encode which proteins? Do the The parents themselves have α-thalassemia trait (mild
different forms vary at their N termini, their C ter- anemia) and microcystosis (abnormally small red
mini, or somewhere in the middle? Estimate how blood cells). Remember that humans have two essen-
many amino acids each of these proteins contains. tially identical Hbα genes (Hbα1 and Hbα2) and that
the genes are autosomal, so normal humans have two
Answer copies of each (Fig. 10.21).
a. The gene is located on the long (q) arm of human a. If this couple has many conceptions, what percent-
chromosome 4; this position is denoted by the thin red age of these conceptions is expected to result in
vertical line on the chromosome representation (an hydrops fetalis?
idiogram) at the top of the figure. This location (in a b. Two other parents, who come from North Africa,
band called 4q33) is roughly 170 million bp from the also both have α-thalassemia trait, but a genetics
telomere of the small arm of chromosome 4 (from counselor told them that none of their conceptions
where the numbering begins); the total length of this would result in hydrops fetalis. Explain how the
chromosome is about 190 million bp. genetic counselor’s advice could be correct.

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