Honors Genetics Ms. Gaynor

Copyright © 2009 Pearson Education, Inc.

Honors GeneticsMs. Gaynor

Chapter 1Introduction to Genetics


What is Genetics?• the study of how genes act to produce the

characteristics of a living organism.• This course will be divided into 3 areas of

study:• classical genetics• how traits are inherited

• molecular genetics• how DNA encodes traits

• genomics• how all an organism's genes function and

interact.


What will we study in Genetics?

• DNA and its function!• We’ll mostly talk about eukaryotic cells

(like yours) but we will also talk about prokaryotic (bacterial) molecular genetics.

• Topics will include • DNA (gene) interactions• Chromosomal inheritance• Biotechnology• Mutations• Population genetics (evolution and DNA)


Did you know?• Scientist named Mendel 1st started studying

genetics in 1800’s.• BUT…DNA’s structure was discovered in 1953. • Study of heredity called GENETICS evolved

QUICKLY from the days of Gregor Mendel (“Father of Genetics”) to DNA in LESS THAN 100 YRS!

• Discovery of the DOUBLE HELIX launched the era of Molecular Genetics & Biotechnology


What came next in 1980’s?• BIOTECHNOLOGY

• use of living organisms (Ex: bacteria or yeast) or their products to modify human health and the human environment.

I LOVE GENETICS!

I LOVE GENETICS!


What came next in 1980’s?• Biotechnology • Manipulating DNA• Allows us to clone cells/

whole animals • Turn genes “on” and “off”

• Biotechnology is continually expanding….

I’m called Copy Cat.

What’s Your Name?

I’m called Copy Cat.

What’s Your Name?


Why is Biotechnology (Genetic Engineering) Important?

• Biotechnology has been used for • Paternal/Maternal testing and Gene therapy• Forensic science/Criminology• Genetic modification of animal/animal products• Genetic modification of crop plants for:

• Increased insect & viral resistance• nutritional enhancement (new traits)


1st Genetically Modified Animal to be Sold as a Pet

• GloFish (2003)


Biotechnology and Genes

• Gene therapy and genetic testing are important parts of medicine.• Inserting genes in DNA• Turning genes “on” and “off”

WE ARE GLOWING!!!

WE ARE GLOWING!!!


Biotechnology has 4 Applications in Major Industrial Areas

• health care (medical)• Ex: hormone (insulin) production, genetic

testing, cloning

• crop production and agriculture• Ex: GM foods, beer/milk products

• non food (industrial) uses of crops and other products • Ex: Biodegradable plastics and biofuels

• Environmental uses• Ex: bioconversion of waste using genetically

altered bacteria in cleanup of oil spills

Copyright © 2009 Pearson Education, Inc. Table 1.1

Copyright © 2009 Pearson Education, Inc. Figure 1.17

HUMAN GENOME PROJECT

(announced in 2000…completed in

2003)


Genomics, Proteomics, and Bioinformatics are New and

Expanding Fields

• Genomics • studies genome (DNA) sequences

• Proteomics (DNA mRNA protein)• studies protein (amino acid) sequences that

lead to traits and characteristics

• All life has a common origin, and genes with similar functions in different organisms are similar in structure and DNA sequence.


How do scientists study Genetics?

• Use MODEL ORGANISMS• An organism whose genetic material has been

altered by genetic engineering techniques• Model organisms for genetic study meet certain

criteria:• easy to grow• short life cycle • produce many offspring• relatively inexpensive• easy to manipulate/mutate

• “KNOCK OUT” or “TURN OFF” genes then look for consequences


What are some common MODEL organisms?

• E. Coli bacteria • Yeast • Nematode (round) worms called C.

Elegans• Fruit Fly called Drosophila melanogaster • Common Mouse


Why not use HUMANS?• Too big• 100 trillion cells (excluding RBC’s)• 5-6 feet tall

• ~40,000 genes on 46 chromosomes• 6 FEET of DNA

• Lifespan is long (40-75 years on average)

• New generation ~every 25 years• Hard to mutate! Wait…it’s not

ethical either!• HUMANS ARE NOT AN

EXPERIMENTAL ORGANISM


E. Coli bacteria (prokaryote)• Commonly found in human digestive system• 4288 genes on 1 chromosome • Rapid growth • E. coli cells can double in number after only 20

minutes.

• Simple food needs• VERY easy to manipulate its DNA• Making recombinant DNA using plasmids

• Taught us about:• Viral diseases and reproduction


Yeast (unicellular, eukaryote)

• Very small and easy to find• 4000 line up to make 1 inch!

• Reproduces easily every 90 minutes

• 6000 genes on 6 chromosomes • 31% are equivalent to human genes

• Its ENTIRE genome of DNA was completely sequenced in 1996.

• Originally taught us about:• Human reproduction and

cancer


C. Elegans (Round worm) (multicellular, eukaryote)

• Very small• 1 mm long!

• Hermaphrodites (male & female parts) • Life span: 2-3 weeks• New offspring EVERY 3 days• 19,099 genes • 40% are equivalent to human genes

• Taught us about:• Cell suicide (apoptosis) and cell health,

animal development


Fruit Fly called Drosophila melanogaster (multicellular, eukaryote)

• Small• 4 mm long!

• Life span: 2-3 months• New offspring EVERY 10 days• 13,600 genes • 50% are equivalent to human genes

• Its ENTIRE genome of DNA was completely sequenced in 2000.

• Lots of mutations to study!• Taught us about:• Animal development, neurons, behavior, cancer


Common Mouse(multicellular, eukaryote)

• CLOSEST relative to human among the “MODELS”• Vertebrates & mammals like humans

• Life span: 2 years• New offspring EVERY 9 weeks• ~40,000 genes (same as humans)• ~99% are equivalent to human genes

• Taught us about:• Human disease, emotions, memory,

reproduction


Human Disease Genes ALSO Found in Model Organisms

• Flies, worms, and yeast share genes with humans for DISEASE, such as:• Cardiac Disease • Deafness• Pancreatic Cancer (flies only)• Duchenne Muscular Dystrophy (NOT yeast)• Skin Cancer• Wilson’s Disease• Colon Cancer• Leukemia (NOT yeast)• Cystic Fibrosis (NOT yeast)


And now…America’s Next Top “Model”?

• Zebrafish!

• Vertebrate (like mice) • Closer to humans than fruit flies or worms• These fish lay 100’s of translucent eggs

OUTSIDE the female’s body• Can see developmental mutations easily!

That fish sure can

“SMEYES”

That fish sure can

“SMEYES”


We Live in the Age of Genetics

• Genetics is the core of biology. • Helps to understand the functions and

malfunctions of a biological system.

Next up…the study of different cell types!

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Honors Genetics Ms. Gaynor