Studied by 3 PeopleTags & Description
Life begins with…
a complete genome
Human genome project (1990-2003)
Determined complete nucletide sequence of each chromosome
complete nucleotide sequence
Chimpanzee
Corn
E. coli
Fruit fly
Bovine
Mg
megabase=millon base pairs
Genome
the entire set of DNA from an organism
Gene density
number of found along a Mb stretch of DNA
Eukaryotes have larger genomes than prokaryotes
Eukaryotes have more genes than prokaryotes
Within eukaryotes
-no systematic relationship b/w genome size & phenotype
-no crrelation between number of genes and genome size
Humans genes and genome
50k-100k predicted
3000 Mb genome (3Gb)
large multicellular eukaryotes genomes have
lower gene density
Have lowest gene density
humans and other mammals
genome for humans
15 genes/Mb in 3000 Mb genome for humans
genome for C- elegans
200 genes/ Mb in 100 Mb genome for C. elegans
Due alternative splicing of RNA transcripts
Eukaryotes can produce more than one protein per gene
The BEST at alternative splicing
VERTEBRATES
exons
1.5% encoding regions for proteins, rRNA, tRNA
regulatory sequences
5%
introns-non coding elements
20%
makes our genes larger
intergenetic repetitive DNA
45% makes our GENOME larger
transposable genetic element
75%
large segment duplications
6%
make our GENOME larger
44% of human genome
intergenitc (between genes) repetitive DNA
75% of intergentic repetitive DNA is made of
transposable elements
transposons
retrrotraposons
how do genetic modifications occur?
Rearrangement of genes
Duplication of genes
Mutuation of genes
2 types of mobile genetic elements
are common mechanism of genetic modification
Barbara McClintock
corn
Transposons
mobile genetic elements
DNA can be moved around the genome by 2 methods
Leaves a copy of DNA at original site
Copy & paste
No copy of DNA left at original site
Cut & Paste
Transpons happend via transponsase encoded in transposon region
DNA to DNA movement
Most common mobile genetic elements
Retrotransposons
Retrotransposons
RNA intermediate is key
Rerverse transcriptase is encoded in retrotransposons
Retransposons
New copy is inserted in novel location in genome
Retrotransposons
Original copy remains
Copy and paste method through RNA intermediate
Retrotrransposons
Plants with very large genomes, more transposable elements; NOT genes
Barbara Mcclintock
We would not know BArbara
if Barbara studied rice
Nobody believed her until the same thing was described in bacteria
descent with modification
Evolution
Many species were descedants of ancestral species very different from those alive today
Darwin proposed
Changes in genetic composition of a population over time
Evolution
Scala Naturae
Ladder of creation
Perfect & permanent
NO evolution
Aristotle
Father of Taxonomy
Linnaean Taxonomy
Binominal nomenclature
Genus species
NO evolution
Species divinely created
Perfect & PERMANENT
“nested classification”
Carl von Linne
Carolus Linnaeus
know for his mistake!
Evolutionary Theory
Driven by NEED
Mechanismo= Inherit ACQUIRED characteristics
De Lammarck
ACCQUIRED TRAIT
the change is not written in the genome
HERITABLE TRAITS
traits carried in the genome heritable traits can be passed on to future generations
Father Paleontology = study fossils
Cuvier
Examined strata (layers of sedimentary rock)
Observed older fossils=more dissimilar form modern
Cuvier
Established extinctions as a phenomena
Cuvier
Catastrophism as mechanism of evolution
(floods, draught)
Only way to evolve is through disaster/ disturbance
Cuvier
2 Important influences on Darwin
James Hutton
Charles Lyell
Theory of Gradualism
Profund geologic changes were cumulative
slow and continous process
James Hutton
Geologist
Theory of UNIFORMITARIANISM
geologic processes had not changed throught Earth´s history
Charles Lyell
Corn genome has 85%
transposable elements
Based on Hutton and Lyell´s theories, Darwin surmised…
If geologic changes are the result of slow, continuous change, Earth is older than theologians infer.
Slow, subtle, processes presisting for long periods could also act on organism, producing, substantial changes over time.
Father of biogeography
sent Darwin his theory
share credit for similar theories
Darwin was more complete
Natural Selection as mechanism of evolution
A. R. Wallace
Was introudced as mechanism of evolution
Natural Selection
Mechanism of evolution
Natural Selection
Process in which individuals have certain heritable traits survive and reproduce at higher rate than other individuals becuase of those traits.
Natural selection
Increase the match between organisms and their environment
natural selection over time
enviroment changes
individuals move to a new environment.
will result in adaptation to these new conditions, sometime giving rise to new species in the process
natural selection
Individuals do NOT evolve,
POPULATIONS do. A population is the smallest group that can evolve over time
Can act only on heritable traits
natural selction
is favorable in one environment may be useless or even detrimential in another environment
A trait
Organism no longer match
because of climate change: BAD
Supported by an overwhelming amount of scientific evidence
EVOLUTION
4 documentation of evolution
Direct observation of naturla selection
Fossil Record
Homology
Biogeography
Soapberry bug beak length
Based on foof they consume
Direct observation
Editing mechanism
Selects favorable traits
Natural selection
Traits adapative in one environmetn may be detrimental in another
Natural selection
Similarity in characteristic traits from common ancestry
(mammalian forelimb skeletal structure)
Homology
Similarity in chatacteristic traits from common ancestry
May only found during DEVELOPMENT
4 key CHORDATA characteristics:
post-anal tail
pharyngeal archeas
norchord
Dorsal hollow nerve cord
Trace limb structure
Trace skull bones
Fossil Record
The study of the geographic distribution of species
Camelids: continental drift is mechanism
Biogeography
Individuals do not evolve
Populations do
Favored larged break size present in individuals
Natural selection
each finch started and ended drought with original beak size
average beak size of finch population increase
natural selection favored larger beak size present in individuals
smaller beaked finches died;
larged beaked finches lived
individual finches
didn´t evolve
a change in allele frequencies in a population overtime
microevolution
Natural selection
Genetic Drift (change mutation events)
Gene flow (transfer of individual into/out of population
3 mechanism causes microevolution to happen
only mechanism of ADAPTIVE evolution
natural selection
it improve the match between organism and environment
Evolution is possible
because of genetic variation