Griffiths • Wessler • Carroll • Doebley
Introduction to
Genetic Analysis
TENTH EDITION
CHAPTER 1
The Genetics Revolution
in the Life Sciences
© 2012 W. H. Freeman and Company
CHAPTER OUTLINE
1.1
1.2
1.3
1.4
The nature of biological information
How information becomes biological form
Genetics and evolution
Genetics has provided a powerful new approach
to biological research
1.5 Model organisms have been crucial in the
genetics revolution
1.6 Genetics changes society
1.7 Genetics and the future
Life on Earth
Each cell of an organism has a complement of DNA
DNA is biological information
Complementary base pairing
The nuclear genome
A specific human chromosomal landscape
Chromosomal DNA is wrapped around histones
Chromosomal condensation by further coiling
Structural comparison of the genome components of eukaryotes, prokaryotes, and viruses
Transcription and translation in a eukaryote
Gene polymorphisms
The stuff of genetic variation
1 locus (monogenic),
2 different alleles
3 combos possible
Question
In the diploid cells of an organism, there can be _________
different allele(s) of a given single-copy nuclear gene.
a) only one
b) one or two
c) one, two, three, or four
d) many
Question
In a population, there can be _________ allele(s) of a given
single-copy nuclear gene.
a) only one
b) one or two
c) one, two, three, or four
d) many
One DNA double helix becomes two
DNA replication is the basis for the perpetuation of life through time
Question
When referring to two homologous chromosomes in an
individual diploid cell, which of the following statements is most
accurate?
a) These chromosomes will normally carry the same genes, in
the same order.
b) These chromosomes will normally be identical in sequence.
c) These chromosomes will normally carry the same genes,
but often not in the same order.
d) All of the above.
A mutant gene causes albinism
Many human diseases are caused by mutations in single genes
Evolutionary tree based on comparisons of cytochrome c DNA
Two different genetic approaches
Forward genetics (from
phenotype to gene)
• ID the mutant phenotype
• ID morphological,
physiological,
developmental differences
• ID the gene (DNA
sequence)
Reverse genetics (from gene
to phenotype)
• ID a gene
• Mutate, knockout or overexpress the gene
• Analyze morphological,
physiological, or
developmental effects (the
phenotype)
Question
Experiments where researchers knock out a target gene in a
model organism and analyze the effects of this manipulation to
get clues regarding the function of the target gene are
examples of
a) classical genetics.
b) developmental genetics.
c) forward genetics.
d) mendelian genetics.
e) reverse genetics.
Probes can be used to detect specific macromolecules
Question
Which of the following chemical characteristics of DNA forms
the basis for hybridization technologies to detect specific DNA
sequences?
a) Antibodies that recognize DNA bind tightly to it, forming
highly specific probes.
b) Antigen-antibody complexes react specifically with DNA
and form the basis for Western blotting.
c) Single-stranded DNA will bind tightly to a sequence
identical to it.
d) Single-stranded DNA will bind tightly to a sequence
complementary to it.
e) No two DNA sequences are exactly identical.
A probed DNA microarray
PCR primers detect and amplify a specific genomic region
Some organisms used as models in genetic research
Model Systems
Be prepared to present to the class the model system whose genus
name begins with the letter closest to the first letter of your last name.
Arabidopsis thaliana
Drosophilia melanogaster (fruit fly)
Saccharomyces cerevisiae (yeast)
Neurospora crassa (fungi)
E. coli (bacteria)
C. elegans (worm)
Mus musculus (mouse)
A DNA fingerprint