Transcript BIOL 112 – Principles of Zoology

Principles of Genetics
BIOLOGY 310
Professor: Dr. Jennifer Dever
www.usfca.edu/fac-staff/dever
Intro Lecture outline:
I.
What is Genetics?
A.
B.
C.
II.
Overview of the history of genetics
Principles to understanding heredity
Field of Genetics
divided into three branches
What are the fundamental units of
Genetics?
A.
B.
C.
Elements of heredity
Physical basis of heredity = fundamental units
Levels of biological organization in genetics
I. What is Genetics?
A.
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Overview of the history of genetics
Aristotle, Hippocrates – Pangenesis
Spermists vs. Ovists
Charles Darwin
Gregor Mendel
Thomas Hunt Morgan
Genetics – understanding heredity
Heredity = “a : the sum of the qualities and
potentialities genetically derived from one's
ancestors b : the transmission of such
qualities from ancestor to descendant
through the genes”
Geneticists investigate all forms of inherited
variation, as well as the molecular basis
underlying such characteristics
B. Principles to understanding heredity
 All humans are united by a common set of traits,
or observable characteristics
 All of these characteristics are inherited
 Variation exists among individuals
 The environment can have an effect on
characteristics
C. Field of Genetics: divided into 3 branches
1) Transmission genetics

Transmission of genes from generation to
generation (Mendel)
2) Molecular genetics

Structure and function of genes at the
molecular level (Watson & Crick; Avery)
3) Population genetics

Distribution and behavior of genes in
populations (Hardy and Weinberg)
What do geneticists do?
Utilize the scientific method
Basic genetics research
Applied genetics research
We are in the “Age of Genetics”
Alzheimer's Gene Identified
Dual Gene Therapy Suppresses Lung Cancer In Preclinical Test
Potential 'Off-Switch' For HIV Virus Found By Scientists
Genetic Mutation Alters Response To Heart Failure Drugs
Biotechnology
Bioinformatics
Genomics, Proteomics
Gene Therapy
II. What are the fundamental units
of Genetics?
A. Elements of heredity:
Inherited traits are determined
by the elements of heredity
that are transmitted from
parents to offspring in
reproduction
Genes and chromosomes are
the fundamental units of
genetics
B. Physical basis of heredity =
fundamental units
1. DNA = the genetic material
2. Genome = an organism’s basic complement of
DNA
•
•
Haploid (n)
Diploid (2n)
3. Genes = segment of DNA that “codes” for a
particular protein
4. Genes are expressed
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Step one - transcription
Step two - translation
The molecular expression of genes within
cells leads to an organisms’ outwardly
visible traits.
The expression of a gene is a two
step process.
1) One strand of DNA is transcribed
into an RNA strand.
2) And the RNA strand is used to
specify the sequence of amino acids
within a polypeptide.
 The polypeptide then functions
within the cell, thereby influencing an
organisms traits.
C. Levels of biological
organization in genetics:

Genes are expressed at the molecular level
Proteins function at the cellular level

Traits are observed at the organismal level
The occurrence of a trait within a
species is an observation at the
population level
Relationship between
genes & traits
Molecular level
Cellular level
Organismal level
Populational level