First vaccine
cowpox
resistant to smallpox
make other people resistant by putting it on teenage boys
-worked
how vaccination works
begins with harmless version of virus
-bodies will recgonize but not enough to cause seriou disease
-immune system produces antibodies that defnd against virus
-then if we are exposed to harmful version, our bodes are prepared to fight
different antibodies to fight off different attacks
First cell
-genetic instruction to mnufacture proteins to build human being
instructions carried out by nucleotides
-nucleotides= dna base pair
-genes organized in 23 pairs
every pair except 23rd (sex chromosome) is a matched pair
-chromosome carries the same instructions
-always have dominant gene over recessive
germ cells-cells that combine to provide offspring
3% dna is meant for building
97% isnt active in building
97% portion of genome plays role in evolution
-called noncoding DNA
-made up of jumping genes
-related to viruses
mitochondria= produce energy to run cells
-live in all cells
-own heritable DNA
evolution shaped by integration and adaptation of viruses
Theory
genetic chnages product of accidental mutations (rearrange DNA)
-mutations happen when there is an error
-mutations happen when organism exposed to radiation or powerful chemicals
-sun cause mutation
sunspot peaks- energy leaked through magnetic field
occurred during massive flu outbreaks
-antigenic drift- mutation occurs in the DNA of a virus
-random mutation= advantage on its carrier, better chance to live
one species advantage could be anothers disadvantage (ie. virus to humans)
theory wrong: evolution favor a mutation that helps an organism discover adaptations to help survive
single genes have capacity to produce different proteins at once
shuffle/reshuffle to produce array of proteins
complexity- combining parts of one gene with another
not instructions anymore, scientists learn genes are an intricate network of info
McClintock
corn plants experiment
when they were stressed: DNA moving from one place to another (inserting themselves)
-affected nearby genes- turned them on and off
method:
- relocated to specific parts of genome
- mutations triggered by outside influences (environment)
discovered “jumping genes” (transposons)
-suggested evolution could be faster than imagine
-mutations aren’t just random
Remain in an active gene after inserted and make a difference
Example: jumping gene one one line of fruit flies turned them into superhero fruit flies
-resist starvation
-withstand high temp
-life expectancy that was 35% longer
genome gambles on mutation
Cairns
E coli- digestive workhorse in humans
*cannot digest lactose
-starvation is a big threat to bacteria
experiment: deprived E coli of any food except lactose
- bacteria developed mutations that allowed them to lose their lactose intolerance
idea: bacteria targets specific area of their genome where mutations could be an advantage to them
argument idea:
hypermutation- mutation on steroids
helped bacteria produce mutations 100 times faster
-suggests genome has ability to order mutations on demand
Weismann barrier
germ plasma theory- divides the body’s cells into groups
every cell (except germ cell) is a somatic cell
theory: info in somatic cell is never passed on to germ cells
but: some viruses may be able to penetrate the barrier and carry DNA fro somatic to germ cells
germ line mutations- mutations result in a different gene in egg or sperm that produces new trait in offspring
cancer- uncontrolled cell growth caused by mutation in the gene that is supposed to control the growth of cancerous cells
jumping genes help humans in two ways (diversity):
- very active in brain development
- immune system
Antibodies
b-cells- building blocks for antibodies
V(D)J recombination: b-cells seek out instructions for antibody in their DNA, snip away line of instruction for other antibodies and sew rest together
(unlike jumping genes because leaves a little loop)
once antibodies are developed, you always have them
-immune to future infections
Viruses
cannot produce on its own
hijack hosts cellular machinery
retrovirus-offspring born with virus permanently in DNA
HERVs-permanent place in DNA
two different types of jumping genes:
DNA transposons- cut and paste
retrotransposons- copy and paste
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