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Journey into DNA
The genome is here before us;its chromosomes make me and you.We see them here in their most condensed state,each one will in no time be two.
Forty-six of them make up the genome,half are mum’s and half are pop’s.They’ll soon split into two when the cell divides;there will be ninety-two when it stops.
Journey into dna
We zoom in to take a close look at…a single chromosome?Didn’t we say there are two here?Half of this “X” is a clone.
Chromosomes when stained show banding,or areas of light and dark.What causes this trait is its structure,and the denseness of its parts.
Journey into dna
Here we behold a single gene,the unit of inheritance.If you’re short of thin or slim or bald,depends on its transmittance.
Its length can vary greatly,its intricacy can’t be outdone.It can be as short as a hundred bases,Two million is a long one.
Journey into dnaA DNA molecule is very long,when stretched out end to end.To fit inside a small cellit’s developed this knack to bend.
The DNA twists ‘round and ‘roundlike countless Hula Hoops.It creates a cord-like structure,which we called chromatin loops.
The chromatin scaffold is vital,providing much-needed support.From it extend many more loopsthat a ruler would measure as short.
Journey into dnaWe almost see the DNA strandas we look at some nucleosomes.It’s wrapped tightly on those round things,Which are structures called protein histones.
The histones, they carry a plus charge;without it the strand’s in distress.For then the DNA would try to float free,And become a colossal mess.
“It has a helical structure,”Watson and Crick forthrightly insisted.With two sides and the rungs that connect them,the DNA strand looks like a ladder that’s twisted.
Journey into dna
Here is a small piece of the ladder,untwisted to better your view.Please note that the bases displayed here,are paired up in groupings of two.
Note also that there are four letters;and that’s all that they’ll ever be.They comprise the four DNA bases,and they are A, T, C and G.
Development of life-Darwin's theory of evolution
On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life
Natural selection Adaptation Diversity Over-reproduction
Natural selection Produces adaptations Biodiversity arises by
surviving evolution
Development of life-Darwin's theory of evolution
Development of antibiotic resistance in microorganisms
All living organisms have a single common ancestor Each species through time fit somewhere in an
evolutionary Tree of Life.
Development of life-Darwin's theory of evolution
Darwin’s Tree of Life Modern Tree of Life
Gregor Johann Mendel “Father of modern genetics” Australian monk & scientist Studied the inheritance of certain traits in pea plants Discovered the Laws of Inheritance
Development of life-What Darwin didn’t know: Heredity
Development of life-We have found the secret of Life
By 1953 Watson and Crick was on the case,they were the dynamic duo that deciphered DNA.Must be in double helix like a spiral staircase,with Gs married to Cs and Ts paired to As.
We see here the famous arrangementdiscovered by Watson and Crick.Based on the work of Ms. Franklin,Their model was at once declared slick.
Weird Genetics-What is mutation?
A change in genetic information Failure of DNA repair Mutate a sentence!
– The fat cat ate the wee rat. – The fat hat ate the wee rat. (Point mutations)– The fat caa tet hew eer at. (Frame shift mutations)– The fat ate the wee rat. (Deletion)– The fat cat xlw ate the wee rat. (Insertion)– The fat tar eew eht eta tac. (Inversion)
Hereditary mutations Acquired mutations
Beneficial mutations (Murray Grey)
Harmful mutations (Down Syndrome)
Weird Genetics-classification
Natural mutations Human intervention
– Selective Breeding– Genetic Engineering
Weird Genetics-classification
Breeding plants and animals for particular genetic traits (desirable characteristics)
Inbreeding depression Reduced genetic diversity
Weird Genetics-selective breeding
The Liger is the result of breeding a female Tiger to a male Lion.
Ian made a little lamb, little lamb, little lamb.Ian made a little lamb and Dolly was her name.When she grew, she was just like Mom.Just like Mom, just like Mom.Why was she just like Mom?Their DNA’s the same!
Weird Genetics-genetic engineering
Selective change of genetic material by man Technique of removing, modifying or adding
genes to a DNA molecule
Weird Genetics-so what is GE?
Scientists successfully genetically engineered a rat to grow a human ear on its back.
ANDi (DNA inserted spelled backwards): The first genetically modified monkey
Advantages:– Pest resistance– Herbicide tolerance– Disease resistance– Cold tolerance– Drought tolerance– Salinity tolerance– Nutrition– Medicine
Weird Genetics-gm food for thought
Bright face of genetically modified corn plant: pest-infected non-GM (left) and pest-free GM plant (right) planted side-by-side in a field trial. (photo: Dr. Yu Jialin, China Agricultural University)
Disadvantages:• Environmental hazards
o Unintended harm to other organismso Reduced effectiveness of pesticides
• Human health riskso Unknown effects on human health
• Economic concernso Corporate monopolyo Dependence on GM companieso Monoculture
Weird Genetics-gm food for thought
Biotechnology critic Jeremy Rifkin: "It's the ultimate shopping experience: designing your baby.”
Using genetic technologies to modify embryos and choose desirable characteristics
Spare part children?
Weird Genetics-design-a-baby?
Weird Genetics-the genetic menu
MENUTODAY’S SPECIAL• TENNIS CHAMPION $19,000 (LIMITED OFFER!)
APPETISERS• EYE COLOUR BROWN $10,000
BLUE $10,500BLACK $9,500
• HAIR COLOUR BLACK $9,000WHITE $10,000RED $10,500GREEN $12,000 (MUST TRY!)
Weird Genetics-the genetic menu
MENUSIDE ORDERS• SKIN TONE $9,50O• WEIGHT/HEIGHT $11,000
ENTREES• BEAUTY $20,000• INTELLIGENCE $23,000• GENDER $19,500
MAIN COURSE• MUSIC PRODIGY $25,000
Weird Genetics-the genetic menu
MENUMAIN COURSE• GREAT ARTIST $25,000 • NOBEL PRIZE-WINNING SCIENTIST $26,000• GENIUS PHILOSOPHER $26,000• NEXT PRESIDENT OF AMERICA $40,000
DESSERT• WORLD-CLASS SPORTSMAN $25,000• CANCER-FREE BABY $35.000
FOR FULL BABY MAKEOVER $1,500,000TERMS AND CONDITIONS APPLY
Safety issues– Genes introduced at random places in genome– Many genes have more than one effect– Many traits we want to select are influenced by multiple genes
Environmental influence? Discrimination? Imbalance between rich and poor? Loss of humanity? Is it right to experiment on babies? Other moral complications?
Weird Genetics-terms and conditions?
genetic blueprint- Human Genome Project
• Project goals – Identify all the approximately
20,000-25,000 genes in human DNA– Determine the sequences of the 3
billion chemical base pairs that make up human DNA
– Store this information in databases – Improve tools for data analysis– Transfer related technologies to the
private sector– Address the ethical, legal, and social
issues that may arise from project
bibliography• http://www.youtube.com/• http://www.wikipedia.org/• http://www.bionetonline.org/• http://www.dnai.org/• http://www.science-class.net/• http://www.pbs.org/• http://www.amnh.org/ology/?channel=genetics• http://www.fossilmuseum.net/• http://library.thinkquest.org/• http://www.buzzle.com/• http://learn.genetics.utah.edu/• http://ghr.nlm.nih.gov/• http://www.genetichealth.com/• http://www.biology-online.org/• http://science.howstuffworks.com/• http://www.actionbioscience.org/• http://nature.ca/genome/03/a/03a_10_e.cfm
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