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Presentation targeted to teach students about genetic diversity - one of my favorite classes to teach at outreach programs.
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TEARS OF THE CHEETAH - a story of genetic diversity
Dr Karobi Moitra , NCI Frederick
Where do cheetahs stand on the tree of life?Kingdom: Animalia
Phylum : Chordata
Class : Mammalia
Order : CarnivoraFamily : FelidaeGenus: AcinonyxSpecies: A. jubatus
Order : PrimatesFamily : HominidaeGenus : HomoSpecies: H. sapiens
Where did the name ‘cheetah’ come from ?
Sanskrit word : Chitakayah- which means ‘variegated’ body - ‘marks or patches’’
Hindi - ‘Chitah’ English : Cheetah
Cheetah range :
Africa: Niger,Sudan, Ethiopia,Kenya,Tanzania,Namibia,Botswanaetc.
Iran: Khorasan
SE Asia: India?Pakistan?
Some cool cheetah facts :• Cheetah eat gazelles, impala, zebra, hare etc.
• They hunt in early morning or late in the afternoon
• They hunt in groups
• Rely on vision not scent to hunt
• Adult cheetahs weigh ~ 140lb
• Total body length over 6ft
• Have a distinct ‘tear’ streak
How fast can cheetah’s run ? Cheetah’s can run upto 75 mph (120km/h)for 1,500ft or 1min 30 secs.
Acceleration: 1-64 mph in 3 secs
Cheetah Chatter
The African cheetah population was down to around 15,000wild cheetahs
So conservationalists tried to breed them in captivity - thiswas very hard to do
Also cheetah populations were very prone to disease, if afew cheetah were infected with a disease such as FIPV-feline infectious peritonitis virus, the rest become infectedand die
WHY?
Journey to Africa
Mitch Bush (National Zoo) & David Wildt (NCI)boarded a plane to the DeWildt cheetah breedingcenter in Pretoria (South Africa)
They collected blood samples from around 80 cheetahsand brought them back to Stephen O’Briens lab at NCI-Frederick for analysis.
Proteins in the cheetahs blood wereseparated and analyzed using a techniquecalled :
Protein Gel Electrophoresis
Protein Gel Electrophoresis
Mobility shifts (change in the position of a protein band)can identify the different types of enzyme variantsin a cheetah blood sample
Most animals have a 20-50% difference in specific blood proteins(enzymes) called allozymes because they are different varieties of the same protein
However, when Janice Martenson looked at the allozymesIn the cheetah blood samples she found that cheetahs were Identical for 52 allozymes across the board.
What did this mean?
Cheetahs seemed to be almost genetic clones ofeach other….but more evidence was needed !
DNA
RNA PROTEIN
The double helix
Genetic diversity
Back to Africa !
MHC genes are extremely variable
They are responsible for graft rejection
Skin grafts from 6 unrelated cheetahs were done
If these graft were accepted and grew it meant that these cheetahs were nearly genetically identical to each other = very little genetic diversity
All 6 cheetahs accepted the grafts
Most cheetahs are almost identical clones of each other !
That is why they are more susceptible to disease !
How did this happen?
The “Bottleneck Effect”
12,000yaPleistoceneGreat mammalExtinction
Tears of the cheetah - the legend“A young female cheetah climbed into a warm caveto slumber through a harsh winter in Europe. When she and her cubs crept out in springtime, they meta different world, one in which the cheetahs were (almost)gone - victims of a global holocaust”
……and she cried for them
http://www.cheetahkids.com/
Save the cheetah !
References / Websites
www.wikipedia.org
www.cheetah.org
www.cheetahkids.com/
Tears of the Cheetah by Stephen J . O’Brien
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