Principles of GeneticsPrinciples of GeneticsBIOLOGY 310BIOLOGY 310

Professor: Dr. Jennifer DeverProfessor: Dr. Jennifer Dever

www.usfca.edu/fac-staff/deverwww.usfca.edu/fac-staff/dever

Intro Lecture outline:Intro Lecture outline:

I.I. What is Genetics?What is Genetics?A.A. Overview of the history of geneticsOverview of the history of geneticsB.B. Principles to understanding heredityPrinciples to understanding heredityC.C. Field of Genetics Field of Genetics

divided into three branches divided into three branches

II.II. What are the fundamental units of What are the fundamental units of Genetics?Genetics?

A.A. Elements of heredityElements of heredityB.B. Physical basis of heredity = fundamental unitsPhysical basis of heredity = fundamental unitsC.C. Levels of biological organization in geneticsLevels of biological organization in genetics

I. What is Genetics?I. What is Genetics?

A.A. Overview of the history of geneticsOverview of the history of genetics Aristotle, Hippocrates – PangenesisAristotle, Hippocrates – Pangenesis Spermists vs. OvistsSpermists vs. Ovists Charles Darwin Charles Darwin Gregor MendelGregor Mendel Thomas Hunt MorganThomas Hunt Morgan

Genetics – understanding heredityGenetics – understanding heredity

HeredityHeredity = “ = “aa :: the sum of the qualities and the sum of the qualities and potentialities genetically derived from one's potentialities genetically derived from one's ancestors ancestors bb :: the transmission of such the transmission of such qualities from ancestor to descendant qualities from ancestor to descendant through the genes”through the genes”

Geneticists investigate all forms of Geneticists investigate all forms of inheritedinherited variation, as well as the molecular basis variation, as well as the molecular basis underlying such characteristicsunderlying such characteristics

B.B. Principles to understanding heredityPrinciples to understanding heredity

All humans are united by a common set of traits, All humans are united by a common set of traits, or observable characteristicsor observable characteristics

All of these characteristics are All of these characteristics are inheritedinherited Variation exists among individualsVariation exists among individuals The environment can have an effect on The environment can have an effect on

characteristicscharacteristics

C. Field of Genetics: divided into 3 branchesC. Field of Genetics: divided into 3 branches

1)1) Transmission geneticsTransmission genetics Transmission of genes from generation to Transmission of genes from generation to

generationgeneration (Mendel)(Mendel)

2)2) Molecular geneticsMolecular genetics Structure and function of genes at the Structure and function of genes at the

molecular levelmolecular level (Watson & Crick; Avery)(Watson & Crick; Avery)

3)3) Population geneticsPopulation genetics Distribution and behavior of genes in Distribution and behavior of genes in

populations (Hardy and Weinberg)populations (Hardy and Weinberg)

What do geneticists do?What do geneticists do?Utilize the scientific methodUtilize the scientific method

Basic genetics researchBasic genetics research

Applied genetics researchApplied genetics research

We are in the “Age of Genetics”We are in the “Age of Genetics”

BiotechnologyBiotechnology

BioinformaticsBioinformatics

Genomics, ProteomicsGenomics, Proteomics

Gene TherapyGene Therapy

Alzheimer's Gene IdentifiedDual Gene Therapy Suppresses Lung Cancer In Preclinical TestPotential 'Off-Switch' For HIV Virus Found By ScientistsGenetic Mutation Alters Response To Heart Failure Drugs

II. What are the fundamental units II. What are the fundamental units of Genetics?of Genetics?

A.A. Elements of heredity:Elements of heredity:Inherited traits are determined Inherited traits are determined by the elements of heredity by the elements of heredity that are transmitted from that are transmitted from parents to offspring in parents to offspring in reproductionreproduction

Genes and chromosomesGenes and chromosomes are are the fundamental units of the fundamental units of geneticsgenetics

B. Physical basis of heredity = B. Physical basis of heredity = fundamental unitsfundamental units

1.1. DNA = the genetic materialDNA = the genetic material2.2. Genome = an organism’s basic complement of Genome = an organism’s basic complement of

DNADNA• Haploid (n)Haploid (n)• Diploid (2n)Diploid (2n)

3.3. Genes = segment of DNA that “codes” for a Genes = segment of DNA that “codes” for a particular proteinparticular protein

4.4. Genes are expressed Genes are expressed • Step one - Step one - transcriptiontranscription• Step two - Step two - translationtranslation

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 C. Levels of biological organization in genetics:organization in genetics:

Genes are expressed at the Genes are expressed at the molecular levelmolecular level

Proteins function at the Proteins function at the cellular levelcellular level Traits are observed at the Traits are observed at the organismal levelorganismal level

The occurrence of a trait within a The occurrence of a trait within a species is an observation at the species is an observation at the population levelpopulation level

Relationship between genes & traits

Molecular level

Cellular level

Organismal level

Populational level