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Unformatted text preview: 11. Henry Saturday, October 13, 2007 6:25 PM • Genetics o We share 98% of our genes w/ mice & even more w/ chimps o We have 25,000 genes (thought we had several million) ≈ • 3.5 billion base pairs of DNA An onion has 16 billion Our genome is much smaller than many plants/small animals Primitive plants have more genes than we do o 1/2 of genes in banana are found in people o Every cell in our body has the same genes o More humanlike organism = more genes shared w/ us o More genetic variability in African than anywhere else • Also greatest amount of fossil evidence o Barbara McClintock • Found "jumping genes" in corn AKA: transposons Can relocate themselves from one place to another Changes behavior of genes in new neighborhood Seen in changes in brain development • Changes aren't passed from mom to kids, but the transposons are o "Junk" DNA • Small pieces capable of moving along chromosome changing one gene into another • Counts for a lot of our genetic material o Obesity • Endemic, believed to be caused by DNA • Matter of doubling/tripling genes, not a mutation o Mitochondrial DNA • Not part of chromosomal DNA • Symbiotic relationship • Transferred from mom to kid only Because egg = nutrition, sperm = hotrod • Sperm must be small to be fast enough to survive so no room for mDNA • Shows we all share common ancestor from 100k-200kya Both M&F ancestors • Fossil evidence that 1st modern human originated in Africa Human genetic variability is highest in Africa supporting the idea that they first originated there • Genetic variability of our species is small, suggesting we're relatively new species o Viral DNA • Infiltrates cell to turn genes on/off • Insects often are infected w/ bacteria that gets into germ cells Pass bacteria onto offspring who then carry viral DNA in genes o Variability in species • Primarily seen in dogs Can learn to bond unlike no other animals Follow human gestures/gaze in learning where food is • Believed to be due to domestication • Wolves/foxes won't learn unless domesticated • Europe has highest variation o Neotony • Look like newborns • Young animals learn very quickly • Baby monkeys are very similar • Why are we attracted to baby animals? • Cute animals Conveys innocence? Vulnerability? Cuteness differs from beauty • Cuteness = imperfection • Beauty = perfection o We consider ourselves in same class as great apes • Pound for pound we are much weaker than monkeys, apes, etc. They are ≈ 3x as strong as people Our bones are thinner • Mutation makes us weaker → no longer need heavy bones Smaller frame = better metabolic efficiency Makes jaws & teeth less effective as weapons Brain becomes that tool • In newborn, skull bones aren't fused or fully developed • Allows for brain growth • Is a result of needing to find new ways to make food (cuz of weaker body) • Use to change the world to suit us...
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