Genetics Is the Key to Biology
• Genetics is the science of heredity
and variation
• Study of how traits are passed from
one generation to the next
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Fidelity and variation in
transmission of genetic material
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Genes
• Are the basic structural and
functional unit of genetics
• Are sequences of nucleotides in DNA
• Control cells by directing protein
synthesis
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
The Genetic Material - DNA
(Deoxyribonucleic Acid)
•Composed of Nucleotide subunits
•Nucleotides are composed of
Deoxyribose (sugar)
Phosphate group
Bases
A (Adenine), T (Thymine)
G (Guanine) or C (Cytosine)
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
DNA Is a Double Helix
http://www.biologycorner.com/resources/DNA-colored.gif
Credit: © Science VU/NIH/Visuals Unlimited
DNA model.
35685
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
The Genetic Code Is Universal
• Sequence of nucleotides determines
how the protein is produced from the
gene
• Mutations are changes on the DNA
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Gene Product = Protein
Fig. 1.2
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Chromosomes
• Genes are
arranged on
chromosomes
Karyotype
Fig. 1.6
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
How Are Genes Transmitted from
Parent to Offspring?
• Gregor Mendel
demonstrated the
principles of
inheritance
• Conducted
experiments on
transmission of
traits in peas
Fig. 1.3
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Approaches
• Transmission Genetics
• Pedigree Analysis
• Cytogenetics
• Molecular Genetics
• Population Genetics
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Transmission Genetics
• Studies the pattern of inheritance
that results when traits are passed
from generation to generation
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Pedigree Analysis
• Family history is
used to
construct the
pattern of how a
trait is passed
from generation
to generation
Fig. 1.5
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Cytogenetics
• Studies
chromosome
number and
structure
Fig. 1.6
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Karyotype of Down’s syndrome
http://www.ucl.ac.uk/~ucbhjow/bmsi/lec7_images/47_xx_21.gif
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Molecular Genetics
• Uses recombinant DNA technology to
identify, isolate, clone, and analyze
genes
• Tremendous impact in the last 40
years
• Debate over social, legal and ethical
issues
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Population Genetics
• Identifies how much genetic variation
exists in populations
• Investigates factors, such as migration,
population size, and natural selection, that
change the frequency of a specific gene
over time
• Coupled with DNA technology, investigates
evolutionary history and DNA identification
techniques
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Tracing ancestry of the Cohanim;
Thomas Jefferson/Sally Hemings
Lemba
Cohanim
http://www.pbs.org/wgbh/nova/israel/familygene.html
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Uses of Genetics
• Basic Research
Information about how genes function
What happens when they do not work?
• Applied Research
Commercial products in healthcare,
industry, and agriculture
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Genetics and Social Policy
• Eugenics
• Genetic Technology
• Human Genome Project
• Health Care
• Recombinant DNA Technology
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Genetic Technology
• Recombinant DNA
• Important for
Research
Genetic testing
Gene therapy
Biotechnology
Fig. 1.10
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Human Genome Project
• Public and private research
• Sequence the entire human genome
• First draft in 2001 completed in 2003
• 3 billion nucleotides
• 35,000 genes
• Genomics focuses on the organization
and function of the genomes
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Health Care
• 10 million children and
adults in U.S. suffer
from a genetic
disorder
• Development of
genetic testing
identifies individuals
at risk and allows us
to develop new
treatments
Fig. 1.11
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Recombinant DNA Technology
• Genetically modified food - plants and animals
• Production of human proteins to treat disease
How should this technology be used?
What are the ethical, legal, and social concerns?
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
Timeline of Recent Changes
Chapter 1 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning
